libsanitizer: Intercept __makecontext_v2 on Solaris/SPARC [PR113785]

c-c++-common/asan/swapcontext-test-1.c FAILs on Solaris/SPARC:

FAIL: c-c++-common/asan/swapcontext-test-1.c   -O0  execution test
FAIL: c-c++-common/asan/swapcontext-test-1.c   -O1  execution test
FAIL: c-c++-common/asan/swapcontext-test-1.c   -O2  execution test
FAIL: c-c++-common/asan/swapcontext-test-1.c   -O2 -flto  execution test
FAIL: c-c++-common/asan/swapcontext-test-1.c -O2 -flto -flto-partition=none
execution test
FAIL: c-c++-common/asan/swapcontext-test-1.c -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions execution test
FAIL: c-c++-common/asan/swapcontext-test-1.c   -O3 -g  execution test
FAIL: c-c++-common/asan/swapcontext-test-1.c   -Os  execution test

As detailed in PR sanitizer/113785, this happens because an ABI change
in Solaris 10/SPARC caused the external symbol for makecontext to be
changed to __makecontext_v2, which isn't intercepted.

The following patch, submitted upstream at
https://github.com/llvm/llvm-project/pull/81588, fixes that.

Tested on sparc-sun-solaris2.11 and i386-pc-solaris2.11.

2024-02-16  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	libsanitizer:
	PR sanitizer/113785
	* asan/asan_interceptors.cpp: Cherry-pick llvm-project revision
	8c2033719a843a1880427a5e8caa5563248bce78.

libsanitizer/asan/asan_interceptors.cpp

@@ -347,8 +347,16 @@ static void ClearShadowMemoryForContextStack(uptr stack, uptr ssize) {
   PoisonShadow(bottom, ssize, 0);
 }
 
+// Since Solaris 10/SPARC, ucp->uc_stack.ss_sp refers to the stack base address
+// as on other targets.  For binary compatibility, the new version uses a
+// different external name, so we intercept that.
+#    if SANITIZER_SOLARIS && defined(__sparc__)
+INTERCEPTOR(void, __makecontext_v2, struct ucontext_t *ucp, void (*func)(),
+            int argc, ...) {
+#    else
 INTERCEPTOR(void, makecontext, struct ucontext_t *ucp, void (*func)(), int argc,
             ...) {
+#    endif
   va_list ap;
   uptr args[64];
   // We don't know a better way to forward ... into REAL function. We can
@@ -368,7 +376,11 @@ INTERCEPTOR(void, makecontext, struct ucontext_t *ucp, void (*func)(), int argc,
       ENUMERATE_ARRAY_16(0), ENUMERATE_ARRAY_16(16), ENUMERATE_ARRAY_16(32), \
           ENUMERATE_ARRAY_16(48)
 
+#    if SANITIZER_SOLARIS && defined(__sparc__)
+  REAL(__makecontext_v2)
+#    else
   REAL(makecontext)
+#    endif
   ((struct ucontext_t *)ucp, func, argc, ENUMERATE_ARRAY_64());
 
 #    undef ENUMERATE_ARRAY_4
@@ -783,7 +795,12 @@ void InitializeAsanInterceptors() {
 
 #  if ASAN_INTERCEPT_SWAPCONTEXT
   ASAN_INTERCEPT_FUNC(swapcontext);
+  // See the makecontext interceptor above for an explanation.
+#    if SANITIZER_SOLARIS && defined(__sparc__)
+  ASAN_INTERCEPT_FUNC(__makecontext_v2);
+#    else
   ASAN_INTERCEPT_FUNC(makecontext);
+#    endif
 #  endif
 #  if ASAN_INTERCEPT__LONGJMP
   ASAN_INTERCEPT_FUNC(_longjmp);