[ASan] Disable instrumentation for inalloca variables.

inalloca variables were not treated as static allocas, therefore didn't
participate in regular stack instrumentation. We don't want them to
participate in dynamic alloca instrumentation as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252213 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 538cc850295a78bb44802a22babe7361f7115309..1c51264d7376860fe750df5dce94f08b6b74358c 100644 (file)
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -840,7 +840,10 @@ bool AddressSanitizer::isInterestingAlloca(AllocaInst &AI) {
        getAllocaSizeInBytes(&AI) > 0 &&
        // We are only interested in allocas not promotable to registers.
        // Promotable allocas are common under -O0.
-       (!ClSkipPromotableAllocas || !isAllocaPromotable(&AI)));
+       (!ClSkipPromotableAllocas || !isAllocaPromotable(&AI)) &&
+       // inalloca allocas are not treated as static, and we don't want
+       // dynamic alloca instrumentation for them as well.
+       !AI.isUsedWithInAlloca());
 
   ProcessedAllocas[&AI] = IsInteresting;
   return IsInteresting;

diff --git a/test/Instrumentation/AddressSanitizer/instrument-dynamic-allocas.ll b/test/Instrumentation/AddressSanitizer/instrument-dynamic-allocas.ll
index ceaf0e6fcfb6d473fc1560d90437ca3e2dea3caa..f6354b1ee59db2fb6fb5c5dfafc3d6f5fe02b84b 100644 (file)
--- a/test/Instrumentation/AddressSanitizer/instrument-dynamic-allocas.ll
+++ b/test/Instrumentation/AddressSanitizer/instrument-dynamic-allocas.ll
@@ -7,8 +7,10 @@ target triple = "x86_64-unknown-linux-gnu"
 
 define void @foo(i32 %len) sanitize_address {
 entry:
+; CHECK-ALLOCA-LABEL: define void @foo
 ; CHECK-ALLOCA: __asan_alloca_poison
 ; CHECK-ALLOCA: __asan_allocas_unpoison
+; CHECK-ALLOCA: ret void
   %0 = alloca i32, align 4
   %1 = alloca i8*
   store volatile i32 %len, i32* %0, align 4
@@ -19,3 +21,17 @@ entry:
   ret void
 }
 
+; Test that dynamic alloca is not used for inalloca variables.
+define void @has_inalloca() uwtable sanitize_address {
+; CHECK-ALLOCA-LABEL: define void @has_inalloca
+; CHECK-ALLOCA-NOT: __asan_alloca_poison
+; CHECK-ALLOCA-NOT: __asan_alloca_unpoison
+; CHECK-ALLOCA: ret void
+entry:
+  %t = alloca inalloca i32
+  store i32 42, i32* %t
+  call void @pass_inalloca(i32* inalloca %t)
+  ret void
+}
+
+declare void @pass_inalloca(i32* inalloca)