Do not instrument malloc implementation variables

Since the heap is reconstructed upon state transfer, the old malloc
state is discarded.  In order to avoid state transfer errors, we can
and in fact must discard the internal state of the malloc
implementation.  This patch achieves this by using the sectionify
pass to mark the variables in the libminc malloc object as state that
must be skipped during state transfer.

Change-Id: Ie330f582c8bd45f37a878ea41fa0f9d4a18045e1

minix/lib/libminc/Makefile

@@ -263,6 +263,13 @@ CLEANFILES+= ${f:C/\.o/.bc/}
 CPPFLAGS.${i}+=	-I${LIBCDIR}/stdlib
 .endfor
 
+CPPFLAGS.malloc.c+= -D_LIBSYS
+# Avoid magic instrumentation of the malloc data variables, since the heap is
+# reconstructed upon state transfer. We do need to instrument the malloc
+# functions, since we need to hook their mmap/munmap calls.
+SECTIONIFY.malloc.c+= -sectionify-no-override \
+	-sectionify-data-section-map=.*/magic_malloc_data
+
 .for f in \
 	strcspn.o
 ${f} ${f:C/\.o/.bc/}:	${LIBCDIR}/string/${f:C/\.o/.c/}
@@ -294,8 +301,6 @@ CLEANFILES+= ${f:C/\.o/.bc/}
 .endif # ${USE_BITCODE:Uno} == "yes"
 .endfor
 
-CPPFLAGS.malloc.c+= -D_LIBSYS
-
 .for f in \
 	brksize.o _do_kernel_call_intr.o get_minix_kerninfo.o _ipc.o ucontext.o
 ${f} ${f:C/\.o/.bc/}:	${LIBMINIXCARCHDIR}/sys/${f:C/\.o/.S/}

minix/llvm/include/magic_common.h

@@ -55,6 +55,8 @@
 #define MAGIC_HIDDEN_ARRAY_PREFIX           ".arr.magic"
 #define MAGIC_HIDDEN_STR_PREFIX             ".str.magic"
 
+#define MAGIC_MALLOC_VARS_SECTION_PREFIX    "magic_malloc_data"
+
 /* Magic configuration. */
 #ifndef MAGIC_OUTPUT_CTL
 #define MAGIC_OUTPUT_CTL                    0

minix/llvm/passes/magic/MagicPass.cpp

@@ -68,7 +68,7 @@ MMAPCtlFunction("magic-mmap-ctlfunc",
 static cl::opt<std::string>
 MagicDataSections("magic-data-sections",
     cl::desc("Specify all the colon-separated magic data section regexes not to instrument"),
-    cl::init("^" MAGIC_STATIC_VARS_SECTION_PREFIX ".*$:^" UNBL_SECTION_PREFIX ".*$"), cl::NotHidden, cl::ValueRequired);
+    cl::init("^" MAGIC_STATIC_VARS_SECTION_PREFIX ".*$:^" UNBL_SECTION_PREFIX ".*$:^" MAGIC_MALLOC_VARS_SECTION_PREFIX ".*$"), cl::NotHidden, cl::ValueRequired);
 
 static cl::opt<std::string>
 MagicFunctionSections("magic-function-sections",

share/mk/bsd.lib.mk

@@ -207,12 +207,17 @@ SHLIB_SHFLAGS+= -L ${DESTDIR}/usr/lib
 SHLIB_SHFLAGS+= -Wl,-plugin=${GOLD_PLUGIN} \
 		-Wl,-plugin-opt=-disable-opt
 
+SECTIONIFYPASS?=${NETBSDSRCDIR}/minix/llvm/bin/sectionify.so
+
 .S.bc: ${.TARGET:.bc=.o}
 	rm -f ${.TARGET}
 	ln ${.TARGET:.bc=.o} ${.TARGET}
 .c.bc:
 	${_MKTARGET_COMPILE}
 	${COMPILE.c} ${COPTS.${.IMPSRC:T}} ${CPUFLAGS.${.IMPSRC:T}} ${CPPFLAGS.${.IMPSRC:T}} ${.IMPSRC} -o ${.TARGET} -flto
+	if [ -n '${SECTIONIFY.${.IMPSRC:T}}' ]; then \
+		${OPT} -load ${SECTIONIFYPASS} -sectionify ${SECTIONIFY.${.IMPSRC:T}} -o ${.TARGET}.tmp ${.TARGET} && mv -f ${.TARGET}.tmp ${.TARGET}; \
+	fi
 
 .cc.bc .cxx.bc .cpp.bc:
 	${_MKTARGET_COMPILE}