Compiler-rt changes for dynamic-alloca-for-stack-variables change.

[samsonov]

Summary

See http://reviews.llvm.org/D6465 for details / discussion.

[kcc]

Code LGTM, but let me see the LLVM part in more detail...

lib/asan/asan_fake_stack.cc

201

Update comment?

[samsonov]

• Remove the extra argument of __asan_stack_malloc function: instead, calculate SP inside ASan runtime.

lib/asan/asan_fake_stack.cc

201

Done

[samsonov]

r224063

lib/asan/asan_fake_stack.cc

 static FakeStack *GetFakeStackFast() {
   if (FakeStack *fs = GetTLSFakeStack())
     return fs;
   if (!__asan_option_detect_stack_use_after_return)
     return 0;
   return GetFakeStack();
 }
 
-ALWAYS_INLINE uptr OnMalloc(uptr class_id, uptr size, uptr real_stack) {
+ALWAYS_INLINE uptr OnMalloc(uptr class_id, uptr size) {
   FakeStack *fs = GetFakeStackFast();
-  if (!fs) return real_stack;
+  if (!fs) return 0;
+  uptr local_stack;
+  uptr real_stack = reinterpret_cast<uptr>(&local_stack);
   FakeFrame *ff = fs->Allocate(fs->stack_size_log(), class_id, real_stack);
-  if (!ff)
-    return real_stack;  // Out of fake stack, return the real one.
+  if (!ff) return 0;  // Out of fake stack.
   uptr ptr = reinterpret_cast<uptr>(ff);
   SetShadow(ptr, size, class_id, 0);
   return ptr;
 }
 
-ALWAYS_INLINE void OnFree(uptr ptr, uptr class_id, uptr size, uptr real_stack) {
-  if (ptr == real_stack)
-    return;
+ALWAYS_INLINE void OnFree(uptr ptr, uptr class_id, uptr size) {
   FakeStack::Deallocate(ptr, class_id);
   SetShadow(ptr, size, class_id, kMagic8);
 }
 
 }  // namespace __asan
 
 // ---------------------- Interface ---------------- {{{1
 using namespace __asan;
 #define DEFINE_STACK_MALLOC_FREE_WITH_CLASS_ID(class_id)                       \
   extern "C" SANITIZER_INTERFACE_ATTRIBUTE uptr                                \
-  __asan_stack_malloc_##class_id(uptr size, uptr real_stack) {                 \
-    return OnMalloc(class_id, size, real_stack);                               \
+      __asan_stack_malloc_##class_id(uptr size) {                              \
+    return OnMalloc(class_id, size);                                           \
   }                                                                            \
   extern "C" SANITIZER_INTERFACE_ATTRIBUTE void __asan_stack_free_##class_id(  \
-      uptr ptr, uptr size, uptr real_stack) {                                  \
-    OnFree(ptr, class_id, size, real_stack);                                   \
+      uptr ptr, uptr size) {                                                   \
+    OnFree(ptr, class_id, size);                                               \
   }
 
 DEFINE_STACK_MALLOC_FREE_WITH_CLASS_ID(0)
 DEFINE_STACK_MALLOC_FREE_WITH_CLASS_ID(1)
 DEFINE_STACK_MALLOC_FREE_WITH_CLASS_ID(2)
 DEFINE_STACK_MALLOC_FREE_WITH_CLASS_ID(3)
 DEFINE_STACK_MALLOC_FREE_WITH_CLASS_ID(4)
 DEFINE_STACK_MALLOC_FREE_WITH_CLASS_ID(5)

lib/asan/asan_init_version.h

extern "C" {
   // __asan_init function name.  Objects built with incompatible ASan ABI
   // versions will not link with run-time.
   // Changes between ABI versions:
   // v1=>v2: added 'module_name' to __asan_global
   // v2=>v3: stack frame description (created by the compiler)
   //         contains the function PC as the 3-rd field (see
   //         DescribeAddressIfStack).
   // v3=>v4: added '__asan_global_source_location' to __asan_global.
-  #define __asan_init __asan_init_v4
-  #define __asan_init_name "__asan_init_v4"
+  // v4=>v5: changed the semantics and format of __asan_stack_malloc_ and
+  //         __asan_stack_free_ functions.
+  #define __asan_init __asan_init_v5
+  #define __asan_init_name "__asan_init_v5"
 }
 
 #endif  // ASAN_INIT_VERSION_H