[PATCH] D23708: [asan] Fix size of shadow incorrectly calculated in r279178

[Vitaly Buka via llvm-commits]

vitalybuka created this revision.
vitalybuka added a reviewer: eugenis.
vitalybuka added a subscriber: llvm-commits.

r279178 generates 8 times more stores than necessary.

https://reviews.llvm.org/D23708

Files:
  lib/Transforms/Instrumentation/AddressSanitizer.cpp
  test/Instrumentation/AddressSanitizer/stack-poisoning.ll

Index: test/Instrumentation/AddressSanitizer/stack-poisoning.ll
===================================================================
--- test/Instrumentation/AddressSanitizer/stack-poisoning.ll
+++ test/Instrumentation/AddressSanitizer/stack-poisoning.ll
@@ -44,6 +44,7 @@
   ; CHECK-UAR: store i64 -723401728380766731
   ; CHECK-UAR: store i64 -723401728380766731
   ; CHECK-UAR: store i64 -723401728380766731
+  ; CHECK-UAR-NOT: store i64
   ; CHECK-UAR: store i8 0
   ; CHECK-UAR-NOT: store
   ; CHECK-UAR: label
Index: lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -2237,10 +2237,8 @@
       IRBuilder<> IRBPoison(ThenTerm);
       if (StackMallocIdx <= 4) {
         int ClassSize = kMinStackMallocSize << StackMallocIdx;
-        if ((int)ShadowBytesAfterReturn.size() != ClassSize) {
-          ShadowBytesAfterReturn.resize(ClassSize,
-                                        kAsanStackUseAfterReturnMagic);
-        }
+        ShadowBytesAfterReturn.resize(ClassSize >> Mapping.Scale,
+                                      kAsanStackUseAfterReturnMagic);
         poisonRedZones(ShadowBytesAfterReturn, IRBPoison, ShadowBase, true);
         Value *SavedFlagPtrPtr = IRBPoison.CreateAdd(
             FakeStack,


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