1704 lines
62 KiB
C++
1704 lines
62 KiB
C++
//===--- CGException.cpp - Emit LLVM Code for C++ exceptions --------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This contains code dealing with C++ exception related code generation.
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//
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//===----------------------------------------------------------------------===//
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#include "CodeGenFunction.h"
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#include "CGCleanup.h"
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#include "CGObjCRuntime.h"
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#include "TargetInfo.h"
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#include "clang/AST/StmtCXX.h"
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#include "clang/AST/StmtObjC.h"
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#include "llvm/IR/Intrinsics.h"
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#include "llvm/Support/CallSite.h"
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using namespace clang;
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using namespace CodeGen;
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static llvm::Constant *getAllocateExceptionFn(CodeGenModule &CGM) {
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// void *__cxa_allocate_exception(size_t thrown_size);
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.Int8PtrTy, CGM.SizeTy, /*IsVarArgs=*/false);
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return CGM.CreateRuntimeFunction(FTy, "__cxa_allocate_exception");
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}
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static llvm::Constant *getFreeExceptionFn(CodeGenModule &CGM) {
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// void __cxa_free_exception(void *thrown_exception);
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
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return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
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}
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static llvm::Constant *getThrowFn(CodeGenModule &CGM) {
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// void __cxa_throw(void *thrown_exception, std::type_info *tinfo,
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// void (*dest) (void *));
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llvm::Type *Args[3] = { CGM.Int8PtrTy, CGM.Int8PtrTy, CGM.Int8PtrTy };
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
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return CGM.CreateRuntimeFunction(FTy, "__cxa_throw");
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}
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static llvm::Constant *getReThrowFn(CodeGenModule &CGM) {
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// void __cxa_rethrow();
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, /*IsVarArgs=*/false);
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return CGM.CreateRuntimeFunction(FTy, "__cxa_rethrow");
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}
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static llvm::Constant *getGetExceptionPtrFn(CodeGenModule &CGM) {
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// void *__cxa_get_exception_ptr(void*);
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.Int8PtrTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
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return CGM.CreateRuntimeFunction(FTy, "__cxa_get_exception_ptr");
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}
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static llvm::Constant *getBeginCatchFn(CodeGenModule &CGM) {
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// void *__cxa_begin_catch(void*);
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.Int8PtrTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
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return CGM.CreateRuntimeFunction(FTy, "__cxa_begin_catch");
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}
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static llvm::Constant *getEndCatchFn(CodeGenModule &CGM) {
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// void __cxa_end_catch();
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, /*IsVarArgs=*/false);
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return CGM.CreateRuntimeFunction(FTy, "__cxa_end_catch");
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}
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static llvm::Constant *getUnexpectedFn(CodeGenModule &CGM) {
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// void __cxa_call_unexpected(void *thrown_exception);
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
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return CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
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}
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llvm::Constant *CodeGenFunction::getUnwindResumeFn() {
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(VoidTy, Int8PtrTy, /*IsVarArgs=*/false);
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if (CGM.getLangOpts().SjLjExceptions)
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return CGM.CreateRuntimeFunction(FTy, "_Unwind_SjLj_Resume");
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return CGM.CreateRuntimeFunction(FTy, "_Unwind_Resume");
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}
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llvm::Constant *CodeGenFunction::getUnwindResumeOrRethrowFn() {
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(VoidTy, Int8PtrTy, /*IsVarArgs=*/false);
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if (CGM.getLangOpts().SjLjExceptions)
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return CGM.CreateRuntimeFunction(FTy, "_Unwind_SjLj_Resume_or_Rethrow");
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return CGM.CreateRuntimeFunction(FTy, "_Unwind_Resume_or_Rethrow");
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}
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static llvm::Constant *getTerminateFn(CodeGenModule &CGM) {
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// void __terminate();
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, /*IsVarArgs=*/false);
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StringRef name;
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// In C++, use std::terminate().
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if (CGM.getLangOpts().CPlusPlus)
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name = "_ZSt9terminatev"; // FIXME: mangling!
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else if (CGM.getLangOpts().ObjC1 &&
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CGM.getLangOpts().ObjCRuntime.hasTerminate())
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name = "objc_terminate";
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else
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name = "abort";
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return CGM.CreateRuntimeFunction(FTy, name);
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}
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static llvm::Constant *getCatchallRethrowFn(CodeGenModule &CGM,
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StringRef Name) {
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llvm::FunctionType *FTy =
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llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
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return CGM.CreateRuntimeFunction(FTy, Name);
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}
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namespace {
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/// The exceptions personality for a function.
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struct EHPersonality {
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const char *PersonalityFn;
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// If this is non-null, this personality requires a non-standard
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// function for rethrowing an exception after a catchall cleanup.
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// This function must have prototype void(void*).
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const char *CatchallRethrowFn;
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static const EHPersonality &get(const LangOptions &Lang);
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static const EHPersonality GNU_C;
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static const EHPersonality GNU_C_SJLJ;
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static const EHPersonality GNU_ObjC;
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static const EHPersonality GNUstep_ObjC;
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static const EHPersonality GNU_ObjCXX;
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static const EHPersonality NeXT_ObjC;
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static const EHPersonality GNU_CPlusPlus;
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static const EHPersonality GNU_CPlusPlus_SJLJ;
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};
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}
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const EHPersonality EHPersonality::GNU_C = { "__gcc_personality_v0", 0 };
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const EHPersonality EHPersonality::GNU_C_SJLJ = { "__gcc_personality_sj0", 0 };
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const EHPersonality EHPersonality::NeXT_ObjC = { "__objc_personality_v0", 0 };
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const EHPersonality EHPersonality::GNU_CPlusPlus = { "__gxx_personality_v0", 0};
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const EHPersonality
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EHPersonality::GNU_CPlusPlus_SJLJ = { "__gxx_personality_sj0", 0 };
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const EHPersonality
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EHPersonality::GNU_ObjC = {"__gnu_objc_personality_v0", "objc_exception_throw"};
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const EHPersonality
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EHPersonality::GNU_ObjCXX = { "__gnustep_objcxx_personality_v0", 0 };
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const EHPersonality
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EHPersonality::GNUstep_ObjC = { "__gnustep_objc_personality_v0", 0 };
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static const EHPersonality &getCPersonality(const LangOptions &L) {
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if (L.SjLjExceptions)
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return EHPersonality::GNU_C_SJLJ;
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return EHPersonality::GNU_C;
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}
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static const EHPersonality &getObjCPersonality(const LangOptions &L) {
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switch (L.ObjCRuntime.getKind()) {
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case ObjCRuntime::FragileMacOSX:
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return getCPersonality(L);
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case ObjCRuntime::MacOSX:
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case ObjCRuntime::iOS:
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return EHPersonality::NeXT_ObjC;
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case ObjCRuntime::GNUstep:
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if (L.ObjCRuntime.getVersion() >= VersionTuple(1, 7))
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return EHPersonality::GNUstep_ObjC;
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// fallthrough
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case ObjCRuntime::GCC:
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case ObjCRuntime::ObjFW:
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return EHPersonality::GNU_ObjC;
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}
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llvm_unreachable("bad runtime kind");
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}
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static const EHPersonality &getCXXPersonality(const LangOptions &L) {
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if (L.SjLjExceptions)
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return EHPersonality::GNU_CPlusPlus_SJLJ;
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else
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return EHPersonality::GNU_CPlusPlus;
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}
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/// Determines the personality function to use when both C++
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/// and Objective-C exceptions are being caught.
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static const EHPersonality &getObjCXXPersonality(const LangOptions &L) {
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switch (L.ObjCRuntime.getKind()) {
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// The ObjC personality defers to the C++ personality for non-ObjC
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// handlers. Unlike the C++ case, we use the same personality
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// function on targets using (backend-driven) SJLJ EH.
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case ObjCRuntime::MacOSX:
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case ObjCRuntime::iOS:
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return EHPersonality::NeXT_ObjC;
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// In the fragile ABI, just use C++ exception handling and hope
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// they're not doing crazy exception mixing.
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case ObjCRuntime::FragileMacOSX:
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return getCXXPersonality(L);
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// The GCC runtime's personality function inherently doesn't support
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// mixed EH. Use the C++ personality just to avoid returning null.
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case ObjCRuntime::GCC:
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case ObjCRuntime::ObjFW: // XXX: this will change soon
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return EHPersonality::GNU_ObjC;
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case ObjCRuntime::GNUstep:
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return EHPersonality::GNU_ObjCXX;
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}
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llvm_unreachable("bad runtime kind");
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}
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const EHPersonality &EHPersonality::get(const LangOptions &L) {
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if (L.CPlusPlus && L.ObjC1)
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return getObjCXXPersonality(L);
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else if (L.CPlusPlus)
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return getCXXPersonality(L);
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else if (L.ObjC1)
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return getObjCPersonality(L);
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else
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return getCPersonality(L);
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}
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static llvm::Constant *getPersonalityFn(CodeGenModule &CGM,
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const EHPersonality &Personality) {
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llvm::Constant *Fn =
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CGM.CreateRuntimeFunction(llvm::FunctionType::get(CGM.Int32Ty, true),
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Personality.PersonalityFn);
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return Fn;
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}
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static llvm::Constant *getOpaquePersonalityFn(CodeGenModule &CGM,
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const EHPersonality &Personality) {
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llvm::Constant *Fn = getPersonalityFn(CGM, Personality);
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return llvm::ConstantExpr::getBitCast(Fn, CGM.Int8PtrTy);
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}
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/// Check whether a personality function could reasonably be swapped
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/// for a C++ personality function.
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static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn) {
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for (llvm::Constant::use_iterator
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I = Fn->use_begin(), E = Fn->use_end(); I != E; ++I) {
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llvm::User *User = *I;
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// Conditionally white-list bitcasts.
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if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(User)) {
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if (CE->getOpcode() != llvm::Instruction::BitCast) return false;
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if (!PersonalityHasOnlyCXXUses(CE))
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return false;
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continue;
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}
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// Otherwise, it has to be a landingpad instruction.
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llvm::LandingPadInst *LPI = dyn_cast<llvm::LandingPadInst>(User);
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if (!LPI) return false;
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for (unsigned I = 0, E = LPI->getNumClauses(); I != E; ++I) {
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// Look for something that would've been returned by the ObjC
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// runtime's GetEHType() method.
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llvm::Value *Val = LPI->getClause(I)->stripPointerCasts();
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if (LPI->isCatch(I)) {
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// Check if the catch value has the ObjC prefix.
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if (llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Val))
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// ObjC EH selector entries are always global variables with
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// names starting like this.
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if (GV->getName().startswith("OBJC_EHTYPE"))
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return false;
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} else {
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// Check if any of the filter values have the ObjC prefix.
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llvm::Constant *CVal = cast<llvm::Constant>(Val);
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for (llvm::User::op_iterator
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II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II) {
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if (llvm::GlobalVariable *GV =
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cast<llvm::GlobalVariable>((*II)->stripPointerCasts()))
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// ObjC EH selector entries are always global variables with
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// names starting like this.
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if (GV->getName().startswith("OBJC_EHTYPE"))
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return false;
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}
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}
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}
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}
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return true;
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}
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/// Try to use the C++ personality function in ObjC++. Not doing this
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/// can cause some incompatibilities with gcc, which is more
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/// aggressive about only using the ObjC++ personality in a function
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/// when it really needs it.
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void CodeGenModule::SimplifyPersonality() {
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// If we're not in ObjC++ -fexceptions, there's nothing to do.
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if (!LangOpts.CPlusPlus || !LangOpts.ObjC1 || !LangOpts.Exceptions)
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return;
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// Both the problem this endeavors to fix and the way the logic
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// above works is specific to the NeXT runtime.
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if (!LangOpts.ObjCRuntime.isNeXTFamily())
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return;
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const EHPersonality &ObjCXX = EHPersonality::get(LangOpts);
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const EHPersonality &CXX = getCXXPersonality(LangOpts);
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if (&ObjCXX == &CXX)
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return;
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assert(std::strcmp(ObjCXX.PersonalityFn, CXX.PersonalityFn) != 0 &&
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"Different EHPersonalities using the same personality function.");
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llvm::Function *Fn = getModule().getFunction(ObjCXX.PersonalityFn);
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// Nothing to do if it's unused.
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if (!Fn || Fn->use_empty()) return;
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// Can't do the optimization if it has non-C++ uses.
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if (!PersonalityHasOnlyCXXUses(Fn)) return;
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// Create the C++ personality function and kill off the old
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// function.
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llvm::Constant *CXXFn = getPersonalityFn(*this, CXX);
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// This can happen if the user is screwing with us.
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if (Fn->getType() != CXXFn->getType()) return;
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Fn->replaceAllUsesWith(CXXFn);
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Fn->eraseFromParent();
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}
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/// Returns the value to inject into a selector to indicate the
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/// presence of a catch-all.
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static llvm::Constant *getCatchAllValue(CodeGenFunction &CGF) {
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// Possibly we should use @llvm.eh.catch.all.value here.
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return llvm::ConstantPointerNull::get(CGF.Int8PtrTy);
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}
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namespace {
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/// A cleanup to free the exception object if its initialization
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/// throws.
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struct FreeException : EHScopeStack::Cleanup {
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llvm::Value *exn;
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FreeException(llvm::Value *exn) : exn(exn) {}
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void Emit(CodeGenFunction &CGF, Flags flags) {
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CGF.EmitNounwindRuntimeCall(getFreeExceptionFn(CGF.CGM), exn);
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}
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};
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}
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// Emits an exception expression into the given location. This
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// differs from EmitAnyExprToMem only in that, if a final copy-ctor
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// call is required, an exception within that copy ctor causes
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// std::terminate to be invoked.
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static void EmitAnyExprToExn(CodeGenFunction &CGF, const Expr *e,
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llvm::Value *addr) {
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// Make sure the exception object is cleaned up if there's an
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// exception during initialization.
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CGF.pushFullExprCleanup<FreeException>(EHCleanup, addr);
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EHScopeStack::stable_iterator cleanup = CGF.EHStack.stable_begin();
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// __cxa_allocate_exception returns a void*; we need to cast this
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// to the appropriate type for the object.
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llvm::Type *ty = CGF.ConvertTypeForMem(e->getType())->getPointerTo();
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llvm::Value *typedAddr = CGF.Builder.CreateBitCast(addr, ty);
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// FIXME: this isn't quite right! If there's a final unelided call
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// to a copy constructor, then according to [except.terminate]p1 we
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// must call std::terminate() if that constructor throws, because
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// technically that copy occurs after the exception expression is
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// evaluated but before the exception is caught. But the best way
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// to handle that is to teach EmitAggExpr to do the final copy
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// differently if it can't be elided.
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CGF.EmitAnyExprToMem(e, typedAddr, e->getType().getQualifiers(),
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/*IsInit*/ true);
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// Deactivate the cleanup block.
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CGF.DeactivateCleanupBlock(cleanup, cast<llvm::Instruction>(typedAddr));
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}
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llvm::Value *CodeGenFunction::getExceptionSlot() {
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if (!ExceptionSlot)
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ExceptionSlot = CreateTempAlloca(Int8PtrTy, "exn.slot");
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return ExceptionSlot;
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}
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llvm::Value *CodeGenFunction::getEHSelectorSlot() {
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if (!EHSelectorSlot)
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EHSelectorSlot = CreateTempAlloca(Int32Ty, "ehselector.slot");
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return EHSelectorSlot;
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}
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llvm::Value *CodeGenFunction::getExceptionFromSlot() {
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return Builder.CreateLoad(getExceptionSlot(), "exn");
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}
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llvm::Value *CodeGenFunction::getSelectorFromSlot() {
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return Builder.CreateLoad(getEHSelectorSlot(), "sel");
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}
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void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E,
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bool KeepInsertionPoint) {
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if (!E->getSubExpr()) {
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EmitNoreturnRuntimeCallOrInvoke(getReThrowFn(CGM),
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ArrayRef<llvm::Value*>());
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// throw is an expression, and the expression emitters expect us
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// to leave ourselves at a valid insertion point.
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if (KeepInsertionPoint)
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EmitBlock(createBasicBlock("throw.cont"));
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return;
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}
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QualType ThrowType = E->getSubExpr()->getType();
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if (ThrowType->isObjCObjectPointerType()) {
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const Stmt *ThrowStmt = E->getSubExpr();
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const ObjCAtThrowStmt S(E->getExprLoc(),
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const_cast<Stmt *>(ThrowStmt));
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CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
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// This will clear insertion point which was not cleared in
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// call to EmitThrowStmt.
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if (KeepInsertionPoint)
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EmitBlock(createBasicBlock("throw.cont"));
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return;
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}
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// Now allocate the exception object.
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llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
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uint64_t TypeSize = getContext().getTypeSizeInChars(ThrowType).getQuantity();
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llvm::Constant *AllocExceptionFn = getAllocateExceptionFn(CGM);
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llvm::CallInst *ExceptionPtr =
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EmitNounwindRuntimeCall(AllocExceptionFn,
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llvm::ConstantInt::get(SizeTy, TypeSize),
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"exception");
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EmitAnyExprToExn(*this, E->getSubExpr(), ExceptionPtr);
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// Now throw the exception.
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llvm::Constant *TypeInfo = CGM.GetAddrOfRTTIDescriptor(ThrowType,
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/*ForEH=*/true);
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|
|
// The address of the destructor. If the exception type has a
|
|
// trivial destructor (or isn't a record), we just pass null.
|
|
llvm::Constant *Dtor = 0;
|
|
if (const RecordType *RecordTy = ThrowType->getAs<RecordType>()) {
|
|
CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl());
|
|
if (!Record->hasTrivialDestructor()) {
|
|
CXXDestructorDecl *DtorD = Record->getDestructor();
|
|
Dtor = CGM.GetAddrOfCXXDestructor(DtorD, Dtor_Complete);
|
|
Dtor = llvm::ConstantExpr::getBitCast(Dtor, Int8PtrTy);
|
|
}
|
|
}
|
|
if (!Dtor) Dtor = llvm::Constant::getNullValue(Int8PtrTy);
|
|
|
|
llvm::Value *args[] = { ExceptionPtr, TypeInfo, Dtor };
|
|
EmitNoreturnRuntimeCallOrInvoke(getThrowFn(CGM), args);
|
|
|
|
// throw is an expression, and the expression emitters expect us
|
|
// to leave ourselves at a valid insertion point.
|
|
if (KeepInsertionPoint)
|
|
EmitBlock(createBasicBlock("throw.cont"));
|
|
}
|
|
|
|
void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
|
|
if (!CGM.getLangOpts().CXXExceptions)
|
|
return;
|
|
|
|
const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
|
|
if (FD == 0)
|
|
return;
|
|
const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
|
|
if (Proto == 0)
|
|
return;
|
|
|
|
ExceptionSpecificationType EST = Proto->getExceptionSpecType();
|
|
if (isNoexceptExceptionSpec(EST)) {
|
|
if (Proto->getNoexceptSpec(getContext()) == FunctionProtoType::NR_Nothrow) {
|
|
// noexcept functions are simple terminate scopes.
|
|
EHStack.pushTerminate();
|
|
}
|
|
} else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
|
|
unsigned NumExceptions = Proto->getNumExceptions();
|
|
EHFilterScope *Filter = EHStack.pushFilter(NumExceptions);
|
|
|
|
for (unsigned I = 0; I != NumExceptions; ++I) {
|
|
QualType Ty = Proto->getExceptionType(I);
|
|
QualType ExceptType = Ty.getNonReferenceType().getUnqualifiedType();
|
|
llvm::Value *EHType = CGM.GetAddrOfRTTIDescriptor(ExceptType,
|
|
/*ForEH=*/true);
|
|
Filter->setFilter(I, EHType);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Emit the dispatch block for a filter scope if necessary.
|
|
static void emitFilterDispatchBlock(CodeGenFunction &CGF,
|
|
EHFilterScope &filterScope) {
|
|
llvm::BasicBlock *dispatchBlock = filterScope.getCachedEHDispatchBlock();
|
|
if (!dispatchBlock) return;
|
|
if (dispatchBlock->use_empty()) {
|
|
delete dispatchBlock;
|
|
return;
|
|
}
|
|
|
|
CGF.EmitBlockAfterUses(dispatchBlock);
|
|
|
|
// If this isn't a catch-all filter, we need to check whether we got
|
|
// here because the filter triggered.
|
|
if (filterScope.getNumFilters()) {
|
|
// Load the selector value.
|
|
llvm::Value *selector = CGF.getSelectorFromSlot();
|
|
llvm::BasicBlock *unexpectedBB = CGF.createBasicBlock("ehspec.unexpected");
|
|
|
|
llvm::Value *zero = CGF.Builder.getInt32(0);
|
|
llvm::Value *failsFilter =
|
|
CGF.Builder.CreateICmpSLT(selector, zero, "ehspec.fails");
|
|
CGF.Builder.CreateCondBr(failsFilter, unexpectedBB, CGF.getEHResumeBlock(false));
|
|
|
|
CGF.EmitBlock(unexpectedBB);
|
|
}
|
|
|
|
// Call __cxa_call_unexpected. This doesn't need to be an invoke
|
|
// because __cxa_call_unexpected magically filters exceptions
|
|
// according to the last landing pad the exception was thrown
|
|
// into. Seriously.
|
|
llvm::Value *exn = CGF.getExceptionFromSlot();
|
|
CGF.EmitRuntimeCall(getUnexpectedFn(CGF.CGM), exn)
|
|
->setDoesNotReturn();
|
|
CGF.Builder.CreateUnreachable();
|
|
}
|
|
|
|
void CodeGenFunction::EmitEndEHSpec(const Decl *D) {
|
|
if (!CGM.getLangOpts().CXXExceptions)
|
|
return;
|
|
|
|
const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
|
|
if (FD == 0)
|
|
return;
|
|
const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
|
|
if (Proto == 0)
|
|
return;
|
|
|
|
ExceptionSpecificationType EST = Proto->getExceptionSpecType();
|
|
if (isNoexceptExceptionSpec(EST)) {
|
|
if (Proto->getNoexceptSpec(getContext()) == FunctionProtoType::NR_Nothrow) {
|
|
EHStack.popTerminate();
|
|
}
|
|
} else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
|
|
EHFilterScope &filterScope = cast<EHFilterScope>(*EHStack.begin());
|
|
emitFilterDispatchBlock(*this, filterScope);
|
|
EHStack.popFilter();
|
|
}
|
|
}
|
|
|
|
void CodeGenFunction::EmitCXXTryStmt(const CXXTryStmt &S) {
|
|
EnterCXXTryStmt(S);
|
|
EmitStmt(S.getTryBlock());
|
|
ExitCXXTryStmt(S);
|
|
}
|
|
|
|
void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
|
|
unsigned NumHandlers = S.getNumHandlers();
|
|
EHCatchScope *CatchScope = EHStack.pushCatch(NumHandlers);
|
|
|
|
for (unsigned I = 0; I != NumHandlers; ++I) {
|
|
const CXXCatchStmt *C = S.getHandler(I);
|
|
|
|
llvm::BasicBlock *Handler = createBasicBlock("catch");
|
|
if (C->getExceptionDecl()) {
|
|
// FIXME: Dropping the reference type on the type into makes it
|
|
// impossible to correctly implement catch-by-reference
|
|
// semantics for pointers. Unfortunately, this is what all
|
|
// existing compilers do, and it's not clear that the standard
|
|
// personality routine is capable of doing this right. See C++ DR 388:
|
|
// http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#388
|
|
QualType CaughtType = C->getCaughtType();
|
|
CaughtType = CaughtType.getNonReferenceType().getUnqualifiedType();
|
|
|
|
llvm::Value *TypeInfo = 0;
|
|
if (CaughtType->isObjCObjectPointerType())
|
|
TypeInfo = CGM.getObjCRuntime().GetEHType(CaughtType);
|
|
else
|
|
TypeInfo = CGM.GetAddrOfRTTIDescriptor(CaughtType, /*ForEH=*/true);
|
|
CatchScope->setHandler(I, TypeInfo, Handler);
|
|
} else {
|
|
// No exception decl indicates '...', a catch-all.
|
|
CatchScope->setCatchAllHandler(I, Handler);
|
|
}
|
|
}
|
|
}
|
|
|
|
llvm::BasicBlock *
|
|
CodeGenFunction::getEHDispatchBlock(EHScopeStack::stable_iterator si) {
|
|
// The dispatch block for the end of the scope chain is a block that
|
|
// just resumes unwinding.
|
|
if (si == EHStack.stable_end())
|
|
return getEHResumeBlock(true);
|
|
|
|
// Otherwise, we should look at the actual scope.
|
|
EHScope &scope = *EHStack.find(si);
|
|
|
|
llvm::BasicBlock *dispatchBlock = scope.getCachedEHDispatchBlock();
|
|
if (!dispatchBlock) {
|
|
switch (scope.getKind()) {
|
|
case EHScope::Catch: {
|
|
// Apply a special case to a single catch-all.
|
|
EHCatchScope &catchScope = cast<EHCatchScope>(scope);
|
|
if (catchScope.getNumHandlers() == 1 &&
|
|
catchScope.getHandler(0).isCatchAll()) {
|
|
dispatchBlock = catchScope.getHandler(0).Block;
|
|
|
|
// Otherwise, make a dispatch block.
|
|
} else {
|
|
dispatchBlock = createBasicBlock("catch.dispatch");
|
|
}
|
|
break;
|
|
}
|
|
|
|
case EHScope::Cleanup:
|
|
dispatchBlock = createBasicBlock("ehcleanup");
|
|
break;
|
|
|
|
case EHScope::Filter:
|
|
dispatchBlock = createBasicBlock("filter.dispatch");
|
|
break;
|
|
|
|
case EHScope::Terminate:
|
|
dispatchBlock = getTerminateHandler();
|
|
break;
|
|
}
|
|
scope.setCachedEHDispatchBlock(dispatchBlock);
|
|
}
|
|
return dispatchBlock;
|
|
}
|
|
|
|
/// Check whether this is a non-EH scope, i.e. a scope which doesn't
|
|
/// affect exception handling. Currently, the only non-EH scopes are
|
|
/// normal-only cleanup scopes.
|
|
static bool isNonEHScope(const EHScope &S) {
|
|
switch (S.getKind()) {
|
|
case EHScope::Cleanup:
|
|
return !cast<EHCleanupScope>(S).isEHCleanup();
|
|
case EHScope::Filter:
|
|
case EHScope::Catch:
|
|
case EHScope::Terminate:
|
|
return false;
|
|
}
|
|
|
|
llvm_unreachable("Invalid EHScope Kind!");
|
|
}
|
|
|
|
llvm::BasicBlock *CodeGenFunction::getInvokeDestImpl() {
|
|
assert(EHStack.requiresLandingPad());
|
|
assert(!EHStack.empty());
|
|
|
|
if (!CGM.getLangOpts().Exceptions)
|
|
return 0;
|
|
|
|
// Check the innermost scope for a cached landing pad. If this is
|
|
// a non-EH cleanup, we'll check enclosing scopes in EmitLandingPad.
|
|
llvm::BasicBlock *LP = EHStack.begin()->getCachedLandingPad();
|
|
if (LP) return LP;
|
|
|
|
// Build the landing pad for this scope.
|
|
LP = EmitLandingPad();
|
|
assert(LP);
|
|
|
|
// Cache the landing pad on the innermost scope. If this is a
|
|
// non-EH scope, cache the landing pad on the enclosing scope, too.
|
|
for (EHScopeStack::iterator ir = EHStack.begin(); true; ++ir) {
|
|
ir->setCachedLandingPad(LP);
|
|
if (!isNonEHScope(*ir)) break;
|
|
}
|
|
|
|
return LP;
|
|
}
|
|
|
|
// This code contains a hack to work around a design flaw in
|
|
// LLVM's EH IR which breaks semantics after inlining. This same
|
|
// hack is implemented in llvm-gcc.
|
|
//
|
|
// The LLVM EH abstraction is basically a thin veneer over the
|
|
// traditional GCC zero-cost design: for each range of instructions
|
|
// in the function, there is (at most) one "landing pad" with an
|
|
// associated chain of EH actions. A language-specific personality
|
|
// function interprets this chain of actions and (1) decides whether
|
|
// or not to resume execution at the landing pad and (2) if so,
|
|
// provides an integer indicating why it's stopping. In LLVM IR,
|
|
// the association of a landing pad with a range of instructions is
|
|
// achieved via an invoke instruction, the chain of actions becomes
|
|
// the arguments to the @llvm.eh.selector call, and the selector
|
|
// call returns the integer indicator. Other than the required
|
|
// presence of two intrinsic function calls in the landing pad,
|
|
// the IR exactly describes the layout of the output code.
|
|
//
|
|
// A principal advantage of this design is that it is completely
|
|
// language-agnostic; in theory, the LLVM optimizers can treat
|
|
// landing pads neutrally, and targets need only know how to lower
|
|
// the intrinsics to have a functioning exceptions system (assuming
|
|
// that platform exceptions follow something approximately like the
|
|
// GCC design). Unfortunately, landing pads cannot be combined in a
|
|
// language-agnostic way: given selectors A and B, there is no way
|
|
// to make a single landing pad which faithfully represents the
|
|
// semantics of propagating an exception first through A, then
|
|
// through B, without knowing how the personality will interpret the
|
|
// (lowered form of the) selectors. This means that inlining has no
|
|
// choice but to crudely chain invokes (i.e., to ignore invokes in
|
|
// the inlined function, but to turn all unwindable calls into
|
|
// invokes), which is only semantically valid if every unwind stops
|
|
// at every landing pad.
|
|
//
|
|
// Therefore, the invoke-inline hack is to guarantee that every
|
|
// landing pad has a catch-all.
|
|
enum CleanupHackLevel_t {
|
|
/// A level of hack that requires that all landing pads have
|
|
/// catch-alls.
|
|
CHL_MandatoryCatchall,
|
|
|
|
/// A level of hack that requires that all landing pads handle
|
|
/// cleanups.
|
|
CHL_MandatoryCleanup,
|
|
|
|
/// No hacks at all; ideal IR generation.
|
|
CHL_Ideal
|
|
};
|
|
const CleanupHackLevel_t CleanupHackLevel = CHL_MandatoryCleanup;
|
|
|
|
llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
|
|
assert(EHStack.requiresLandingPad());
|
|
|
|
EHScope &innermostEHScope = *EHStack.find(EHStack.getInnermostEHScope());
|
|
switch (innermostEHScope.getKind()) {
|
|
case EHScope::Terminate:
|
|
return getTerminateLandingPad();
|
|
|
|
case EHScope::Catch:
|
|
case EHScope::Cleanup:
|
|
case EHScope::Filter:
|
|
if (llvm::BasicBlock *lpad = innermostEHScope.getCachedLandingPad())
|
|
return lpad;
|
|
}
|
|
|
|
// Save the current IR generation state.
|
|
CGBuilderTy::InsertPoint savedIP = Builder.saveAndClearIP();
|
|
SourceLocation SavedLocation;
|
|
if (CGDebugInfo *DI = getDebugInfo()) {
|
|
SavedLocation = DI->getLocation();
|
|
DI->EmitLocation(Builder, CurEHLocation);
|
|
}
|
|
|
|
const EHPersonality &personality = EHPersonality::get(getLangOpts());
|
|
|
|
// Create and configure the landing pad.
|
|
llvm::BasicBlock *lpad = createBasicBlock("lpad");
|
|
EmitBlock(lpad);
|
|
|
|
llvm::LandingPadInst *LPadInst =
|
|
Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty, NULL),
|
|
getOpaquePersonalityFn(CGM, personality), 0);
|
|
|
|
llvm::Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
|
|
Builder.CreateStore(LPadExn, getExceptionSlot());
|
|
llvm::Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
|
|
Builder.CreateStore(LPadSel, getEHSelectorSlot());
|
|
|
|
// Save the exception pointer. It's safe to use a single exception
|
|
// pointer per function because EH cleanups can never have nested
|
|
// try/catches.
|
|
// Build the landingpad instruction.
|
|
|
|
// Accumulate all the handlers in scope.
|
|
bool hasCatchAll = false;
|
|
bool hasCleanup = false;
|
|
bool hasFilter = false;
|
|
SmallVector<llvm::Value*, 4> filterTypes;
|
|
llvm::SmallPtrSet<llvm::Value*, 4> catchTypes;
|
|
for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end();
|
|
I != E; ++I) {
|
|
|
|
switch (I->getKind()) {
|
|
case EHScope::Cleanup:
|
|
// If we have a cleanup, remember that.
|
|
hasCleanup = (hasCleanup || cast<EHCleanupScope>(*I).isEHCleanup());
|
|
continue;
|
|
|
|
case EHScope::Filter: {
|
|
assert(I.next() == EHStack.end() && "EH filter is not end of EH stack");
|
|
assert(!hasCatchAll && "EH filter reached after catch-all");
|
|
|
|
// Filter scopes get added to the landingpad in weird ways.
|
|
EHFilterScope &filter = cast<EHFilterScope>(*I);
|
|
hasFilter = true;
|
|
|
|
// Add all the filter values.
|
|
for (unsigned i = 0, e = filter.getNumFilters(); i != e; ++i)
|
|
filterTypes.push_back(filter.getFilter(i));
|
|
goto done;
|
|
}
|
|
|
|
case EHScope::Terminate:
|
|
// Terminate scopes are basically catch-alls.
|
|
assert(!hasCatchAll);
|
|
hasCatchAll = true;
|
|
goto done;
|
|
|
|
case EHScope::Catch:
|
|
break;
|
|
}
|
|
|
|
EHCatchScope &catchScope = cast<EHCatchScope>(*I);
|
|
for (unsigned hi = 0, he = catchScope.getNumHandlers(); hi != he; ++hi) {
|
|
EHCatchScope::Handler handler = catchScope.getHandler(hi);
|
|
|
|
// If this is a catch-all, register that and abort.
|
|
if (!handler.Type) {
|
|
assert(!hasCatchAll);
|
|
hasCatchAll = true;
|
|
goto done;
|
|
}
|
|
|
|
// Check whether we already have a handler for this type.
|
|
if (catchTypes.insert(handler.Type))
|
|
// If not, add it directly to the landingpad.
|
|
LPadInst->addClause(handler.Type);
|
|
}
|
|
}
|
|
|
|
done:
|
|
// If we have a catch-all, add null to the landingpad.
|
|
assert(!(hasCatchAll && hasFilter));
|
|
if (hasCatchAll) {
|
|
LPadInst->addClause(getCatchAllValue(*this));
|
|
|
|
// If we have an EH filter, we need to add those handlers in the
|
|
// right place in the landingpad, which is to say, at the end.
|
|
} else if (hasFilter) {
|
|
// Create a filter expression: a constant array indicating which filter
|
|
// types there are. The personality routine only lands here if the filter
|
|
// doesn't match.
|
|
SmallVector<llvm::Constant*, 8> Filters;
|
|
llvm::ArrayType *AType =
|
|
llvm::ArrayType::get(!filterTypes.empty() ?
|
|
filterTypes[0]->getType() : Int8PtrTy,
|
|
filterTypes.size());
|
|
|
|
for (unsigned i = 0, e = filterTypes.size(); i != e; ++i)
|
|
Filters.push_back(cast<llvm::Constant>(filterTypes[i]));
|
|
llvm::Constant *FilterArray = llvm::ConstantArray::get(AType, Filters);
|
|
LPadInst->addClause(FilterArray);
|
|
|
|
// Also check whether we need a cleanup.
|
|
if (hasCleanup)
|
|
LPadInst->setCleanup(true);
|
|
|
|
// Otherwise, signal that we at least have cleanups.
|
|
} else if (CleanupHackLevel == CHL_MandatoryCatchall || hasCleanup) {
|
|
if (CleanupHackLevel == CHL_MandatoryCatchall)
|
|
LPadInst->addClause(getCatchAllValue(*this));
|
|
else
|
|
LPadInst->setCleanup(true);
|
|
}
|
|
|
|
assert((LPadInst->getNumClauses() > 0 || LPadInst->isCleanup()) &&
|
|
"landingpad instruction has no clauses!");
|
|
|
|
// Tell the backend how to generate the landing pad.
|
|
Builder.CreateBr(getEHDispatchBlock(EHStack.getInnermostEHScope()));
|
|
|
|
// Restore the old IR generation state.
|
|
Builder.restoreIP(savedIP);
|
|
if (CGDebugInfo *DI = getDebugInfo())
|
|
DI->EmitLocation(Builder, SavedLocation);
|
|
|
|
return lpad;
|
|
}
|
|
|
|
namespace {
|
|
/// A cleanup to call __cxa_end_catch. In many cases, the caught
|
|
/// exception type lets us state definitively that the thrown exception
|
|
/// type does not have a destructor. In particular:
|
|
/// - Catch-alls tell us nothing, so we have to conservatively
|
|
/// assume that the thrown exception might have a destructor.
|
|
/// - Catches by reference behave according to their base types.
|
|
/// - Catches of non-record types will only trigger for exceptions
|
|
/// of non-record types, which never have destructors.
|
|
/// - Catches of record types can trigger for arbitrary subclasses
|
|
/// of the caught type, so we have to assume the actual thrown
|
|
/// exception type might have a throwing destructor, even if the
|
|
/// caught type's destructor is trivial or nothrow.
|
|
struct CallEndCatch : EHScopeStack::Cleanup {
|
|
CallEndCatch(bool MightThrow) : MightThrow(MightThrow) {}
|
|
bool MightThrow;
|
|
|
|
void Emit(CodeGenFunction &CGF, Flags flags) {
|
|
if (!MightThrow) {
|
|
CGF.EmitNounwindRuntimeCall(getEndCatchFn(CGF.CGM));
|
|
return;
|
|
}
|
|
|
|
CGF.EmitRuntimeCallOrInvoke(getEndCatchFn(CGF.CGM));
|
|
}
|
|
};
|
|
}
|
|
|
|
/// Emits a call to __cxa_begin_catch and enters a cleanup to call
|
|
/// __cxa_end_catch.
|
|
///
|
|
/// \param EndMightThrow - true if __cxa_end_catch might throw
|
|
static llvm::Value *CallBeginCatch(CodeGenFunction &CGF,
|
|
llvm::Value *Exn,
|
|
bool EndMightThrow) {
|
|
llvm::CallInst *call =
|
|
CGF.EmitNounwindRuntimeCall(getBeginCatchFn(CGF.CGM), Exn);
|
|
|
|
CGF.EHStack.pushCleanup<CallEndCatch>(NormalAndEHCleanup, EndMightThrow);
|
|
|
|
return call;
|
|
}
|
|
|
|
/// A "special initializer" callback for initializing a catch
|
|
/// parameter during catch initialization.
|
|
static void InitCatchParam(CodeGenFunction &CGF,
|
|
const VarDecl &CatchParam,
|
|
llvm::Value *ParamAddr,
|
|
SourceLocation Loc) {
|
|
// Load the exception from where the landing pad saved it.
|
|
llvm::Value *Exn = CGF.getExceptionFromSlot();
|
|
|
|
CanQualType CatchType =
|
|
CGF.CGM.getContext().getCanonicalType(CatchParam.getType());
|
|
llvm::Type *LLVMCatchTy = CGF.ConvertTypeForMem(CatchType);
|
|
|
|
// If we're catching by reference, we can just cast the object
|
|
// pointer to the appropriate pointer.
|
|
if (isa<ReferenceType>(CatchType)) {
|
|
QualType CaughtType = cast<ReferenceType>(CatchType)->getPointeeType();
|
|
bool EndCatchMightThrow = CaughtType->isRecordType();
|
|
|
|
// __cxa_begin_catch returns the adjusted object pointer.
|
|
llvm::Value *AdjustedExn = CallBeginCatch(CGF, Exn, EndCatchMightThrow);
|
|
|
|
// We have no way to tell the personality function that we're
|
|
// catching by reference, so if we're catching a pointer,
|
|
// __cxa_begin_catch will actually return that pointer by value.
|
|
if (const PointerType *PT = dyn_cast<PointerType>(CaughtType)) {
|
|
QualType PointeeType = PT->getPointeeType();
|
|
|
|
// When catching by reference, generally we should just ignore
|
|
// this by-value pointer and use the exception object instead.
|
|
if (!PointeeType->isRecordType()) {
|
|
|
|
// Exn points to the struct _Unwind_Exception header, which
|
|
// we have to skip past in order to reach the exception data.
|
|
unsigned HeaderSize =
|
|
CGF.CGM.getTargetCodeGenInfo().getSizeOfUnwindException();
|
|
AdjustedExn = CGF.Builder.CreateConstGEP1_32(Exn, HeaderSize);
|
|
|
|
// However, if we're catching a pointer-to-record type that won't
|
|
// work, because the personality function might have adjusted
|
|
// the pointer. There's actually no way for us to fully satisfy
|
|
// the language/ABI contract here: we can't use Exn because it
|
|
// might have the wrong adjustment, but we can't use the by-value
|
|
// pointer because it's off by a level of abstraction.
|
|
//
|
|
// The current solution is to dump the adjusted pointer into an
|
|
// alloca, which breaks language semantics (because changing the
|
|
// pointer doesn't change the exception) but at least works.
|
|
// The better solution would be to filter out non-exact matches
|
|
// and rethrow them, but this is tricky because the rethrow
|
|
// really needs to be catchable by other sites at this landing
|
|
// pad. The best solution is to fix the personality function.
|
|
} else {
|
|
// Pull the pointer for the reference type off.
|
|
llvm::Type *PtrTy =
|
|
cast<llvm::PointerType>(LLVMCatchTy)->getElementType();
|
|
|
|
// Create the temporary and write the adjusted pointer into it.
|
|
llvm::Value *ExnPtrTmp = CGF.CreateTempAlloca(PtrTy, "exn.byref.tmp");
|
|
llvm::Value *Casted = CGF.Builder.CreateBitCast(AdjustedExn, PtrTy);
|
|
CGF.Builder.CreateStore(Casted, ExnPtrTmp);
|
|
|
|
// Bind the reference to the temporary.
|
|
AdjustedExn = ExnPtrTmp;
|
|
}
|
|
}
|
|
|
|
llvm::Value *ExnCast =
|
|
CGF.Builder.CreateBitCast(AdjustedExn, LLVMCatchTy, "exn.byref");
|
|
CGF.Builder.CreateStore(ExnCast, ParamAddr);
|
|
return;
|
|
}
|
|
|
|
// Scalars and complexes.
|
|
TypeEvaluationKind TEK = CGF.getEvaluationKind(CatchType);
|
|
if (TEK != TEK_Aggregate) {
|
|
llvm::Value *AdjustedExn = CallBeginCatch(CGF, Exn, false);
|
|
|
|
// If the catch type is a pointer type, __cxa_begin_catch returns
|
|
// the pointer by value.
|
|
if (CatchType->hasPointerRepresentation()) {
|
|
llvm::Value *CastExn =
|
|
CGF.Builder.CreateBitCast(AdjustedExn, LLVMCatchTy, "exn.casted");
|
|
|
|
switch (CatchType.getQualifiers().getObjCLifetime()) {
|
|
case Qualifiers::OCL_Strong:
|
|
CastExn = CGF.EmitARCRetainNonBlock(CastExn);
|
|
// fallthrough
|
|
|
|
case Qualifiers::OCL_None:
|
|
case Qualifiers::OCL_ExplicitNone:
|
|
case Qualifiers::OCL_Autoreleasing:
|
|
CGF.Builder.CreateStore(CastExn, ParamAddr);
|
|
return;
|
|
|
|
case Qualifiers::OCL_Weak:
|
|
CGF.EmitARCInitWeak(ParamAddr, CastExn);
|
|
return;
|
|
}
|
|
llvm_unreachable("bad ownership qualifier!");
|
|
}
|
|
|
|
// Otherwise, it returns a pointer into the exception object.
|
|
|
|
llvm::Type *PtrTy = LLVMCatchTy->getPointerTo(0); // addrspace 0 ok
|
|
llvm::Value *Cast = CGF.Builder.CreateBitCast(AdjustedExn, PtrTy);
|
|
|
|
LValue srcLV = CGF.MakeNaturalAlignAddrLValue(Cast, CatchType);
|
|
LValue destLV = CGF.MakeAddrLValue(ParamAddr, CatchType,
|
|
CGF.getContext().getDeclAlign(&CatchParam));
|
|
switch (TEK) {
|
|
case TEK_Complex:
|
|
CGF.EmitStoreOfComplex(CGF.EmitLoadOfComplex(srcLV, Loc), destLV,
|
|
/*init*/ true);
|
|
return;
|
|
case TEK_Scalar: {
|
|
llvm::Value *ExnLoad = CGF.EmitLoadOfScalar(srcLV, Loc);
|
|
CGF.EmitStoreOfScalar(ExnLoad, destLV, /*init*/ true);
|
|
return;
|
|
}
|
|
case TEK_Aggregate:
|
|
llvm_unreachable("evaluation kind filtered out!");
|
|
}
|
|
llvm_unreachable("bad evaluation kind");
|
|
}
|
|
|
|
assert(isa<RecordType>(CatchType) && "unexpected catch type!");
|
|
|
|
llvm::Type *PtrTy = LLVMCatchTy->getPointerTo(0); // addrspace 0 ok
|
|
|
|
// Check for a copy expression. If we don't have a copy expression,
|
|
// that means a trivial copy is okay.
|
|
const Expr *copyExpr = CatchParam.getInit();
|
|
if (!copyExpr) {
|
|
llvm::Value *rawAdjustedExn = CallBeginCatch(CGF, Exn, true);
|
|
llvm::Value *adjustedExn = CGF.Builder.CreateBitCast(rawAdjustedExn, PtrTy);
|
|
CGF.EmitAggregateCopy(ParamAddr, adjustedExn, CatchType);
|
|
return;
|
|
}
|
|
|
|
// We have to call __cxa_get_exception_ptr to get the adjusted
|
|
// pointer before copying.
|
|
llvm::CallInst *rawAdjustedExn =
|
|
CGF.EmitNounwindRuntimeCall(getGetExceptionPtrFn(CGF.CGM), Exn);
|
|
|
|
// Cast that to the appropriate type.
|
|
llvm::Value *adjustedExn = CGF.Builder.CreateBitCast(rawAdjustedExn, PtrTy);
|
|
|
|
// The copy expression is defined in terms of an OpaqueValueExpr.
|
|
// Find it and map it to the adjusted expression.
|
|
CodeGenFunction::OpaqueValueMapping
|
|
opaque(CGF, OpaqueValueExpr::findInCopyConstruct(copyExpr),
|
|
CGF.MakeAddrLValue(adjustedExn, CatchParam.getType()));
|
|
|
|
// Call the copy ctor in a terminate scope.
|
|
CGF.EHStack.pushTerminate();
|
|
|
|
// Perform the copy construction.
|
|
CharUnits Alignment = CGF.getContext().getDeclAlign(&CatchParam);
|
|
CGF.EmitAggExpr(copyExpr,
|
|
AggValueSlot::forAddr(ParamAddr, Alignment, Qualifiers(),
|
|
AggValueSlot::IsNotDestructed,
|
|
AggValueSlot::DoesNotNeedGCBarriers,
|
|
AggValueSlot::IsNotAliased));
|
|
|
|
// Leave the terminate scope.
|
|
CGF.EHStack.popTerminate();
|
|
|
|
// Undo the opaque value mapping.
|
|
opaque.pop();
|
|
|
|
// Finally we can call __cxa_begin_catch.
|
|
CallBeginCatch(CGF, Exn, true);
|
|
}
|
|
|
|
/// Begins a catch statement by initializing the catch variable and
|
|
/// calling __cxa_begin_catch.
|
|
static void BeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *S) {
|
|
// We have to be very careful with the ordering of cleanups here:
|
|
// C++ [except.throw]p4:
|
|
// The destruction [of the exception temporary] occurs
|
|
// immediately after the destruction of the object declared in
|
|
// the exception-declaration in the handler.
|
|
//
|
|
// So the precise ordering is:
|
|
// 1. Construct catch variable.
|
|
// 2. __cxa_begin_catch
|
|
// 3. Enter __cxa_end_catch cleanup
|
|
// 4. Enter dtor cleanup
|
|
//
|
|
// We do this by using a slightly abnormal initialization process.
|
|
// Delegation sequence:
|
|
// - ExitCXXTryStmt opens a RunCleanupsScope
|
|
// - EmitAutoVarAlloca creates the variable and debug info
|
|
// - InitCatchParam initializes the variable from the exception
|
|
// - CallBeginCatch calls __cxa_begin_catch
|
|
// - CallBeginCatch enters the __cxa_end_catch cleanup
|
|
// - EmitAutoVarCleanups enters the variable destructor cleanup
|
|
// - EmitCXXTryStmt emits the code for the catch body
|
|
// - EmitCXXTryStmt close the RunCleanupsScope
|
|
|
|
VarDecl *CatchParam = S->getExceptionDecl();
|
|
if (!CatchParam) {
|
|
llvm::Value *Exn = CGF.getExceptionFromSlot();
|
|
CallBeginCatch(CGF, Exn, true);
|
|
return;
|
|
}
|
|
|
|
// Emit the local.
|
|
CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
|
|
InitCatchParam(CGF, *CatchParam, var.getObjectAddress(CGF), S->getLocStart());
|
|
CGF.EmitAutoVarCleanups(var);
|
|
}
|
|
|
|
/// Emit the structure of the dispatch block for the given catch scope.
|
|
/// It is an invariant that the dispatch block already exists.
|
|
static void emitCatchDispatchBlock(CodeGenFunction &CGF,
|
|
EHCatchScope &catchScope) {
|
|
llvm::BasicBlock *dispatchBlock = catchScope.getCachedEHDispatchBlock();
|
|
assert(dispatchBlock);
|
|
|
|
// If there's only a single catch-all, getEHDispatchBlock returned
|
|
// that catch-all as the dispatch block.
|
|
if (catchScope.getNumHandlers() == 1 &&
|
|
catchScope.getHandler(0).isCatchAll()) {
|
|
assert(dispatchBlock == catchScope.getHandler(0).Block);
|
|
return;
|
|
}
|
|
|
|
CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveIP();
|
|
CGF.EmitBlockAfterUses(dispatchBlock);
|
|
|
|
// Select the right handler.
|
|
llvm::Value *llvm_eh_typeid_for =
|
|
CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
|
|
|
|
// Load the selector value.
|
|
llvm::Value *selector = CGF.getSelectorFromSlot();
|
|
|
|
// Test against each of the exception types we claim to catch.
|
|
for (unsigned i = 0, e = catchScope.getNumHandlers(); ; ++i) {
|
|
assert(i < e && "ran off end of handlers!");
|
|
const EHCatchScope::Handler &handler = catchScope.getHandler(i);
|
|
|
|
llvm::Value *typeValue = handler.Type;
|
|
assert(typeValue && "fell into catch-all case!");
|
|
typeValue = CGF.Builder.CreateBitCast(typeValue, CGF.Int8PtrTy);
|
|
|
|
// Figure out the next block.
|
|
bool nextIsEnd;
|
|
llvm::BasicBlock *nextBlock;
|
|
|
|
// If this is the last handler, we're at the end, and the next
|
|
// block is the block for the enclosing EH scope.
|
|
if (i + 1 == e) {
|
|
nextBlock = CGF.getEHDispatchBlock(catchScope.getEnclosingEHScope());
|
|
nextIsEnd = true;
|
|
|
|
// If the next handler is a catch-all, we're at the end, and the
|
|
// next block is that handler.
|
|
} else if (catchScope.getHandler(i+1).isCatchAll()) {
|
|
nextBlock = catchScope.getHandler(i+1).Block;
|
|
nextIsEnd = true;
|
|
|
|
// Otherwise, we're not at the end and we need a new block.
|
|
} else {
|
|
nextBlock = CGF.createBasicBlock("catch.fallthrough");
|
|
nextIsEnd = false;
|
|
}
|
|
|
|
// Figure out the catch type's index in the LSDA's type table.
|
|
llvm::CallInst *typeIndex =
|
|
CGF.Builder.CreateCall(llvm_eh_typeid_for, typeValue);
|
|
typeIndex->setDoesNotThrow();
|
|
|
|
llvm::Value *matchesTypeIndex =
|
|
CGF.Builder.CreateICmpEQ(selector, typeIndex, "matches");
|
|
CGF.Builder.CreateCondBr(matchesTypeIndex, handler.Block, nextBlock);
|
|
|
|
// If the next handler is a catch-all, we're completely done.
|
|
if (nextIsEnd) {
|
|
CGF.Builder.restoreIP(savedIP);
|
|
return;
|
|
}
|
|
// Otherwise we need to emit and continue at that block.
|
|
CGF.EmitBlock(nextBlock);
|
|
}
|
|
}
|
|
|
|
void CodeGenFunction::popCatchScope() {
|
|
EHCatchScope &catchScope = cast<EHCatchScope>(*EHStack.begin());
|
|
if (catchScope.hasEHBranches())
|
|
emitCatchDispatchBlock(*this, catchScope);
|
|
EHStack.popCatch();
|
|
}
|
|
|
|
void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
|
|
unsigned NumHandlers = S.getNumHandlers();
|
|
EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
|
|
assert(CatchScope.getNumHandlers() == NumHandlers);
|
|
|
|
// If the catch was not required, bail out now.
|
|
if (!CatchScope.hasEHBranches()) {
|
|
EHStack.popCatch();
|
|
return;
|
|
}
|
|
|
|
// Emit the structure of the EH dispatch for this catch.
|
|
emitCatchDispatchBlock(*this, CatchScope);
|
|
|
|
// Copy the handler blocks off before we pop the EH stack. Emitting
|
|
// the handlers might scribble on this memory.
|
|
SmallVector<EHCatchScope::Handler, 8> Handlers(NumHandlers);
|
|
memcpy(Handlers.data(), CatchScope.begin(),
|
|
NumHandlers * sizeof(EHCatchScope::Handler));
|
|
|
|
EHStack.popCatch();
|
|
|
|
// The fall-through block.
|
|
llvm::BasicBlock *ContBB = createBasicBlock("try.cont");
|
|
|
|
// We just emitted the body of the try; jump to the continue block.
|
|
if (HaveInsertPoint())
|
|
Builder.CreateBr(ContBB);
|
|
|
|
// Determine if we need an implicit rethrow for all these catch handlers;
|
|
// see the comment below.
|
|
bool doImplicitRethrow = false;
|
|
if (IsFnTryBlock)
|
|
doImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
|
|
isa<CXXConstructorDecl>(CurCodeDecl);
|
|
|
|
// Perversely, we emit the handlers backwards precisely because we
|
|
// want them to appear in source order. In all of these cases, the
|
|
// catch block will have exactly one predecessor, which will be a
|
|
// particular block in the catch dispatch. However, in the case of
|
|
// a catch-all, one of the dispatch blocks will branch to two
|
|
// different handlers, and EmitBlockAfterUses will cause the second
|
|
// handler to be moved before the first.
|
|
for (unsigned I = NumHandlers; I != 0; --I) {
|
|
llvm::BasicBlock *CatchBlock = Handlers[I-1].Block;
|
|
EmitBlockAfterUses(CatchBlock);
|
|
|
|
// Catch the exception if this isn't a catch-all.
|
|
const CXXCatchStmt *C = S.getHandler(I-1);
|
|
|
|
// Enter a cleanup scope, including the catch variable and the
|
|
// end-catch.
|
|
RunCleanupsScope CatchScope(*this);
|
|
|
|
// Initialize the catch variable and set up the cleanups.
|
|
BeginCatch(*this, C);
|
|
|
|
// Perform the body of the catch.
|
|
EmitStmt(C->getHandlerBlock());
|
|
|
|
// [except.handle]p11:
|
|
// The currently handled exception is rethrown if control
|
|
// reaches the end of a handler of the function-try-block of a
|
|
// constructor or destructor.
|
|
|
|
// It is important that we only do this on fallthrough and not on
|
|
// return. Note that it's illegal to put a return in a
|
|
// constructor function-try-block's catch handler (p14), so this
|
|
// really only applies to destructors.
|
|
if (doImplicitRethrow && HaveInsertPoint()) {
|
|
EmitRuntimeCallOrInvoke(getReThrowFn(CGM));
|
|
Builder.CreateUnreachable();
|
|
Builder.ClearInsertionPoint();
|
|
}
|
|
|
|
// Fall out through the catch cleanups.
|
|
CatchScope.ForceCleanup();
|
|
|
|
// Branch out of the try.
|
|
if (HaveInsertPoint())
|
|
Builder.CreateBr(ContBB);
|
|
}
|
|
|
|
EmitBlock(ContBB);
|
|
}
|
|
|
|
namespace {
|
|
struct CallEndCatchForFinally : EHScopeStack::Cleanup {
|
|
llvm::Value *ForEHVar;
|
|
llvm::Value *EndCatchFn;
|
|
CallEndCatchForFinally(llvm::Value *ForEHVar, llvm::Value *EndCatchFn)
|
|
: ForEHVar(ForEHVar), EndCatchFn(EndCatchFn) {}
|
|
|
|
void Emit(CodeGenFunction &CGF, Flags flags) {
|
|
llvm::BasicBlock *EndCatchBB = CGF.createBasicBlock("finally.endcatch");
|
|
llvm::BasicBlock *CleanupContBB =
|
|
CGF.createBasicBlock("finally.cleanup.cont");
|
|
|
|
llvm::Value *ShouldEndCatch =
|
|
CGF.Builder.CreateLoad(ForEHVar, "finally.endcatch");
|
|
CGF.Builder.CreateCondBr(ShouldEndCatch, EndCatchBB, CleanupContBB);
|
|
CGF.EmitBlock(EndCatchBB);
|
|
CGF.EmitRuntimeCallOrInvoke(EndCatchFn); // catch-all, so might throw
|
|
CGF.EmitBlock(CleanupContBB);
|
|
}
|
|
};
|
|
|
|
struct PerformFinally : EHScopeStack::Cleanup {
|
|
const Stmt *Body;
|
|
llvm::Value *ForEHVar;
|
|
llvm::Value *EndCatchFn;
|
|
llvm::Value *RethrowFn;
|
|
llvm::Value *SavedExnVar;
|
|
|
|
PerformFinally(const Stmt *Body, llvm::Value *ForEHVar,
|
|
llvm::Value *EndCatchFn,
|
|
llvm::Value *RethrowFn, llvm::Value *SavedExnVar)
|
|
: Body(Body), ForEHVar(ForEHVar), EndCatchFn(EndCatchFn),
|
|
RethrowFn(RethrowFn), SavedExnVar(SavedExnVar) {}
|
|
|
|
void Emit(CodeGenFunction &CGF, Flags flags) {
|
|
// Enter a cleanup to call the end-catch function if one was provided.
|
|
if (EndCatchFn)
|
|
CGF.EHStack.pushCleanup<CallEndCatchForFinally>(NormalAndEHCleanup,
|
|
ForEHVar, EndCatchFn);
|
|
|
|
// Save the current cleanup destination in case there are
|
|
// cleanups in the finally block.
|
|
llvm::Value *SavedCleanupDest =
|
|
CGF.Builder.CreateLoad(CGF.getNormalCleanupDestSlot(),
|
|
"cleanup.dest.saved");
|
|
|
|
// Emit the finally block.
|
|
CGF.EmitStmt(Body);
|
|
|
|
// If the end of the finally is reachable, check whether this was
|
|
// for EH. If so, rethrow.
|
|
if (CGF.HaveInsertPoint()) {
|
|
llvm::BasicBlock *RethrowBB = CGF.createBasicBlock("finally.rethrow");
|
|
llvm::BasicBlock *ContBB = CGF.createBasicBlock("finally.cont");
|
|
|
|
llvm::Value *ShouldRethrow =
|
|
CGF.Builder.CreateLoad(ForEHVar, "finally.shouldthrow");
|
|
CGF.Builder.CreateCondBr(ShouldRethrow, RethrowBB, ContBB);
|
|
|
|
CGF.EmitBlock(RethrowBB);
|
|
if (SavedExnVar) {
|
|
CGF.EmitRuntimeCallOrInvoke(RethrowFn,
|
|
CGF.Builder.CreateLoad(SavedExnVar));
|
|
} else {
|
|
CGF.EmitRuntimeCallOrInvoke(RethrowFn);
|
|
}
|
|
CGF.Builder.CreateUnreachable();
|
|
|
|
CGF.EmitBlock(ContBB);
|
|
|
|
// Restore the cleanup destination.
|
|
CGF.Builder.CreateStore(SavedCleanupDest,
|
|
CGF.getNormalCleanupDestSlot());
|
|
}
|
|
|
|
// Leave the end-catch cleanup. As an optimization, pretend that
|
|
// the fallthrough path was inaccessible; we've dynamically proven
|
|
// that we're not in the EH case along that path.
|
|
if (EndCatchFn) {
|
|
CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
|
|
CGF.PopCleanupBlock();
|
|
CGF.Builder.restoreIP(SavedIP);
|
|
}
|
|
|
|
// Now make sure we actually have an insertion point or the
|
|
// cleanup gods will hate us.
|
|
CGF.EnsureInsertPoint();
|
|
}
|
|
};
|
|
}
|
|
|
|
/// Enters a finally block for an implementation using zero-cost
|
|
/// exceptions. This is mostly general, but hard-codes some
|
|
/// language/ABI-specific behavior in the catch-all sections.
|
|
void CodeGenFunction::FinallyInfo::enter(CodeGenFunction &CGF,
|
|
const Stmt *body,
|
|
llvm::Constant *beginCatchFn,
|
|
llvm::Constant *endCatchFn,
|
|
llvm::Constant *rethrowFn) {
|
|
assert((beginCatchFn != 0) == (endCatchFn != 0) &&
|
|
"begin/end catch functions not paired");
|
|
assert(rethrowFn && "rethrow function is required");
|
|
|
|
BeginCatchFn = beginCatchFn;
|
|
|
|
// The rethrow function has one of the following two types:
|
|
// void (*)()
|
|
// void (*)(void*)
|
|
// In the latter case we need to pass it the exception object.
|
|
// But we can't use the exception slot because the @finally might
|
|
// have a landing pad (which would overwrite the exception slot).
|
|
llvm::FunctionType *rethrowFnTy =
|
|
cast<llvm::FunctionType>(
|
|
cast<llvm::PointerType>(rethrowFn->getType())->getElementType());
|
|
SavedExnVar = 0;
|
|
if (rethrowFnTy->getNumParams())
|
|
SavedExnVar = CGF.CreateTempAlloca(CGF.Int8PtrTy, "finally.exn");
|
|
|
|
// A finally block is a statement which must be executed on any edge
|
|
// out of a given scope. Unlike a cleanup, the finally block may
|
|
// contain arbitrary control flow leading out of itself. In
|
|
// addition, finally blocks should always be executed, even if there
|
|
// are no catch handlers higher on the stack. Therefore, we
|
|
// surround the protected scope with a combination of a normal
|
|
// cleanup (to catch attempts to break out of the block via normal
|
|
// control flow) and an EH catch-all (semantically "outside" any try
|
|
// statement to which the finally block might have been attached).
|
|
// The finally block itself is generated in the context of a cleanup
|
|
// which conditionally leaves the catch-all.
|
|
|
|
// Jump destination for performing the finally block on an exception
|
|
// edge. We'll never actually reach this block, so unreachable is
|
|
// fine.
|
|
RethrowDest = CGF.getJumpDestInCurrentScope(CGF.getUnreachableBlock());
|
|
|
|
// Whether the finally block is being executed for EH purposes.
|
|
ForEHVar = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), "finally.for-eh");
|
|
CGF.Builder.CreateStore(CGF.Builder.getFalse(), ForEHVar);
|
|
|
|
// Enter a normal cleanup which will perform the @finally block.
|
|
CGF.EHStack.pushCleanup<PerformFinally>(NormalCleanup, body,
|
|
ForEHVar, endCatchFn,
|
|
rethrowFn, SavedExnVar);
|
|
|
|
// Enter a catch-all scope.
|
|
llvm::BasicBlock *catchBB = CGF.createBasicBlock("finally.catchall");
|
|
EHCatchScope *catchScope = CGF.EHStack.pushCatch(1);
|
|
catchScope->setCatchAllHandler(0, catchBB);
|
|
}
|
|
|
|
void CodeGenFunction::FinallyInfo::exit(CodeGenFunction &CGF) {
|
|
// Leave the finally catch-all.
|
|
EHCatchScope &catchScope = cast<EHCatchScope>(*CGF.EHStack.begin());
|
|
llvm::BasicBlock *catchBB = catchScope.getHandler(0).Block;
|
|
|
|
CGF.popCatchScope();
|
|
|
|
// If there are any references to the catch-all block, emit it.
|
|
if (catchBB->use_empty()) {
|
|
delete catchBB;
|
|
} else {
|
|
CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveAndClearIP();
|
|
CGF.EmitBlock(catchBB);
|
|
|
|
llvm::Value *exn = 0;
|
|
|
|
// If there's a begin-catch function, call it.
|
|
if (BeginCatchFn) {
|
|
exn = CGF.getExceptionFromSlot();
|
|
CGF.EmitNounwindRuntimeCall(BeginCatchFn, exn);
|
|
}
|
|
|
|
// If we need to remember the exception pointer to rethrow later, do so.
|
|
if (SavedExnVar) {
|
|
if (!exn) exn = CGF.getExceptionFromSlot();
|
|
CGF.Builder.CreateStore(exn, SavedExnVar);
|
|
}
|
|
|
|
// Tell the cleanups in the finally block that we're do this for EH.
|
|
CGF.Builder.CreateStore(CGF.Builder.getTrue(), ForEHVar);
|
|
|
|
// Thread a jump through the finally cleanup.
|
|
CGF.EmitBranchThroughCleanup(RethrowDest);
|
|
|
|
CGF.Builder.restoreIP(savedIP);
|
|
}
|
|
|
|
// Finally, leave the @finally cleanup.
|
|
CGF.PopCleanupBlock();
|
|
}
|
|
|
|
/// In a terminate landing pad, should we use __clang__call_terminate
|
|
/// or just a naked call to std::terminate?
|
|
///
|
|
/// __clang_call_terminate calls __cxa_begin_catch, which then allows
|
|
/// std::terminate to usefully report something about the
|
|
/// violating exception.
|
|
static bool useClangCallTerminate(CodeGenModule &CGM) {
|
|
// Only do this for Itanium-family ABIs in C++ mode.
|
|
return (CGM.getLangOpts().CPlusPlus &&
|
|
CGM.getTarget().getCXXABI().isItaniumFamily());
|
|
}
|
|
|
|
/// Get or define the following function:
|
|
/// void @__clang_call_terminate(i8* %exn) nounwind noreturn
|
|
/// This code is used only in C++.
|
|
static llvm::Constant *getClangCallTerminateFn(CodeGenModule &CGM) {
|
|
llvm::FunctionType *fnTy =
|
|
llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
|
|
llvm::Constant *fnRef =
|
|
CGM.CreateRuntimeFunction(fnTy, "__clang_call_terminate");
|
|
|
|
llvm::Function *fn = dyn_cast<llvm::Function>(fnRef);
|
|
if (fn && fn->empty()) {
|
|
fn->setDoesNotThrow();
|
|
fn->setDoesNotReturn();
|
|
|
|
// What we really want is to massively penalize inlining without
|
|
// forbidding it completely. The difference between that and
|
|
// 'noinline' is negligible.
|
|
fn->addFnAttr(llvm::Attribute::NoInline);
|
|
|
|
// Allow this function to be shared across translation units, but
|
|
// we don't want it to turn into an exported symbol.
|
|
fn->setLinkage(llvm::Function::LinkOnceODRLinkage);
|
|
fn->setVisibility(llvm::Function::HiddenVisibility);
|
|
|
|
// Set up the function.
|
|
llvm::BasicBlock *entry =
|
|
llvm::BasicBlock::Create(CGM.getLLVMContext(), "", fn);
|
|
CGBuilderTy builder(entry);
|
|
|
|
// Pull the exception pointer out of the parameter list.
|
|
llvm::Value *exn = &*fn->arg_begin();
|
|
|
|
// Call __cxa_begin_catch(exn).
|
|
llvm::CallInst *catchCall = builder.CreateCall(getBeginCatchFn(CGM), exn);
|
|
catchCall->setDoesNotThrow();
|
|
catchCall->setCallingConv(CGM.getRuntimeCC());
|
|
|
|
// Call std::terminate().
|
|
llvm::CallInst *termCall = builder.CreateCall(getTerminateFn(CGM));
|
|
termCall->setDoesNotThrow();
|
|
termCall->setDoesNotReturn();
|
|
termCall->setCallingConv(CGM.getRuntimeCC());
|
|
|
|
// std::terminate cannot return.
|
|
builder.CreateUnreachable();
|
|
}
|
|
|
|
return fnRef;
|
|
}
|
|
|
|
llvm::BasicBlock *CodeGenFunction::getTerminateLandingPad() {
|
|
if (TerminateLandingPad)
|
|
return TerminateLandingPad;
|
|
|
|
CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
|
|
|
|
// This will get inserted at the end of the function.
|
|
TerminateLandingPad = createBasicBlock("terminate.lpad");
|
|
Builder.SetInsertPoint(TerminateLandingPad);
|
|
|
|
// Tell the backend that this is a landing pad.
|
|
const EHPersonality &Personality = EHPersonality::get(CGM.getLangOpts());
|
|
llvm::LandingPadInst *LPadInst =
|
|
Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty, NULL),
|
|
getOpaquePersonalityFn(CGM, Personality), 0);
|
|
LPadInst->addClause(getCatchAllValue(*this));
|
|
|
|
llvm::CallInst *terminateCall;
|
|
if (useClangCallTerminate(CGM)) {
|
|
// Extract out the exception pointer.
|
|
llvm::Value *exn = Builder.CreateExtractValue(LPadInst, 0);
|
|
terminateCall = EmitNounwindRuntimeCall(getClangCallTerminateFn(CGM), exn);
|
|
} else {
|
|
terminateCall = EmitNounwindRuntimeCall(getTerminateFn(CGM));
|
|
}
|
|
terminateCall->setDoesNotReturn();
|
|
Builder.CreateUnreachable();
|
|
|
|
// Restore the saved insertion state.
|
|
Builder.restoreIP(SavedIP);
|
|
|
|
return TerminateLandingPad;
|
|
}
|
|
|
|
llvm::BasicBlock *CodeGenFunction::getTerminateHandler() {
|
|
if (TerminateHandler)
|
|
return TerminateHandler;
|
|
|
|
CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
|
|
|
|
// Set up the terminate handler. This block is inserted at the very
|
|
// end of the function by FinishFunction.
|
|
TerminateHandler = createBasicBlock("terminate.handler");
|
|
Builder.SetInsertPoint(TerminateHandler);
|
|
llvm::CallInst *terminateCall;
|
|
if (useClangCallTerminate(CGM)) {
|
|
// Load the exception pointer.
|
|
llvm::Value *exn = getExceptionFromSlot();
|
|
terminateCall = EmitNounwindRuntimeCall(getClangCallTerminateFn(CGM), exn);
|
|
} else {
|
|
terminateCall = EmitNounwindRuntimeCall(getTerminateFn(CGM));
|
|
}
|
|
terminateCall->setDoesNotReturn();
|
|
Builder.CreateUnreachable();
|
|
|
|
// Restore the saved insertion state.
|
|
Builder.restoreIP(SavedIP);
|
|
|
|
return TerminateHandler;
|
|
}
|
|
|
|
llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
|
|
if (EHResumeBlock) return EHResumeBlock;
|
|
|
|
CGBuilderTy::InsertPoint SavedIP = Builder.saveIP();
|
|
|
|
// We emit a jump to a notional label at the outermost unwind state.
|
|
EHResumeBlock = createBasicBlock("eh.resume");
|
|
Builder.SetInsertPoint(EHResumeBlock);
|
|
|
|
const EHPersonality &Personality = EHPersonality::get(CGM.getLangOpts());
|
|
|
|
// This can always be a call because we necessarily didn't find
|
|
// anything on the EH stack which needs our help.
|
|
const char *RethrowName = Personality.CatchallRethrowFn;
|
|
if (RethrowName != 0 && !isCleanup) {
|
|
EmitRuntimeCall(getCatchallRethrowFn(CGM, RethrowName),
|
|
getExceptionFromSlot())
|
|
->setDoesNotReturn();
|
|
} else {
|
|
switch (CleanupHackLevel) {
|
|
case CHL_MandatoryCatchall:
|
|
// In mandatory-catchall mode, we need to use
|
|
// _Unwind_Resume_or_Rethrow, or whatever the personality's
|
|
// equivalent is.
|
|
EmitRuntimeCall(getUnwindResumeOrRethrowFn(),
|
|
getExceptionFromSlot())
|
|
->setDoesNotReturn();
|
|
break;
|
|
case CHL_MandatoryCleanup: {
|
|
// In mandatory-cleanup mode, we should use 'resume'.
|
|
|
|
// Recreate the landingpad's return value for the 'resume' instruction.
|
|
llvm::Value *Exn = getExceptionFromSlot();
|
|
llvm::Value *Sel = getSelectorFromSlot();
|
|
|
|
llvm::Type *LPadType = llvm::StructType::get(Exn->getType(),
|
|
Sel->getType(), NULL);
|
|
llvm::Value *LPadVal = llvm::UndefValue::get(LPadType);
|
|
LPadVal = Builder.CreateInsertValue(LPadVal, Exn, 0, "lpad.val");
|
|
LPadVal = Builder.CreateInsertValue(LPadVal, Sel, 1, "lpad.val");
|
|
|
|
Builder.CreateResume(LPadVal);
|
|
Builder.restoreIP(SavedIP);
|
|
return EHResumeBlock;
|
|
}
|
|
case CHL_Ideal:
|
|
// In an idealized mode where we don't have to worry about the
|
|
// optimizer combining landing pads, we should just use
|
|
// _Unwind_Resume (or the personality's equivalent).
|
|
EmitRuntimeCall(getUnwindResumeFn(), getExceptionFromSlot())
|
|
->setDoesNotReturn();
|
|
break;
|
|
}
|
|
}
|
|
|
|
Builder.CreateUnreachable();
|
|
|
|
Builder.restoreIP(SavedIP);
|
|
|
|
return EHResumeBlock;
|
|
}
|
|
|
|
void CodeGenFunction::EmitSEHTryStmt(const SEHTryStmt &S) {
|
|
CGM.ErrorUnsupported(&S, "SEH __try");
|
|
}
|