[Asan] Eliminate SHADOW_TO_MEM() macro

Differential Revision: https://reviews.llvm.org/D31592

llvm-svn: 299867

2 files changed, 4 insertions, 2 deletions

diff --git a/compiler-rt/lib/asan/asan_mapping.h b/compiler-rt/lib/asan/asan_mapping.h
index d8e60a4b34a..695740cd982 100644
--- a/compiler-rt/lib/asan/asan_mapping.h
+++ b/compiler-rt/lib/asan/asan_mapping.h
@@ -191,7 +191,6 @@ static const u64 kWindowsShadowOffset32 = 3ULL << 28;  // 0x30000000
 
 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
-#define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
 
 #define kLowMemBeg      0
 #define kLowMemEnd      (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
diff --git a/compiler-rt/lib/asan/asan_thread.cc b/compiler-rt/lib/asan/asan_thread.cc
index 2f9fa81e1ab..aaa32d6ea6d 100644
--- a/compiler-rt/lib/asan/asan_thread.cc
+++ b/compiler-rt/lib/asan/asan_thread.cc
@@ -300,24 +300,27 @@ bool AsanThread::GetStackFrameAccessByAddr(uptr addr,
     return true;
   }
   uptr aligned_addr = addr & ~(SANITIZER_WORDSIZE/8 - 1);  // align addr.
+  uptr mem_ptr = RoundDownTo(aligned_addr, SHADOW_GRANULARITY);
   u8 *shadow_ptr = (u8*)MemToShadow(aligned_addr);
   u8 *shadow_bottom = (u8*)MemToShadow(bottom);
 
   while (shadow_ptr >= shadow_bottom &&
          *shadow_ptr != kAsanStackLeftRedzoneMagic) {
     shadow_ptr--;
+    mem_ptr -= SHADOW_GRANULARITY;
   }
 
   while (shadow_ptr >= shadow_bottom &&
          *shadow_ptr == kAsanStackLeftRedzoneMagic) {
     shadow_ptr--;
+    mem_ptr -= SHADOW_GRANULARITY;
   }
 
   if (shadow_ptr < shadow_bottom) {
     return false;
   }
 
-  uptr* ptr = (uptr*)SHADOW_TO_MEM((uptr)(shadow_ptr + 1));
+  uptr* ptr = (uptr*)(mem_ptr + SHADOW_GRANULARITY);
   CHECK(ptr[0] == kCurrentStackFrameMagic);
   access->offset = addr - (uptr)ptr;
   access->frame_pc = ptr[2];