[ASan] Emit lifetime markers for local variables in -fsanitize=use-after-scope mode

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178538 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index d59c876d71c26d1db25eea1ea0fbe5a25954d053..1255e654dc44cf0310d0bc7261210ae501fb4957 100644 (file)
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -786,6 +786,9 @@ static bool shouldUseMemSetPlusStoresToInitialize(llvm::Constant *Init,
 /// Should we use the LLVM lifetime intrinsics for the given local variable?
 static bool shouldUseLifetimeMarkers(CodeGenFunction &CGF, const VarDecl &D,
                                      unsigned Size) {
+  // Always emit lifetime markers in -fsanitize=use-after-scope mode.
+  if (CGF.getLangOpts().Sanitize.UseAfterScope)
+    return true;
   // For now, only in optimized builds.
   if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0)
     return false;

diff --git a/test/CodeGen/sanitize-use-after-scope.c b/test/CodeGen/sanitize-use-after-scope.c
new file mode 100644 (file)
index 0000000..8f92038
--- /dev/null
+++ b/test/CodeGen/sanitize-use-after-scope.c
@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -S -emit-llvm -o - -fsanitize=address,use-after-scope %s \
+// RUN:     | FileCheck %s -check-prefix=USE-AFTER-SCOPE
+// RUN: %clang_cc1 -S -emit-llvm -o - -fsanitize=address %s \
+// RUN:     | FileCheck %s -check-prefix=ADDRESS-ONLY
+
+extern int bar(char *A, int n);
+
+// ADDRESS-ONLY-NOT: @llvm.lifetime.start
+int foo (int n) {
+  if (n) {
+    // USE-AFTER-SCOPE: @llvm.lifetime.start(i64 10, i8* {{.*}})
+    char A[10];
+    return bar(A, 1);
+    // USE-AFTER-SCOPE: @llvm.lifetime.end(i64 10, i8* {{.*}})
+  } else {
+    // USE-AFTER-SCOPE: @llvm.lifetime.start(i64 20, i8* {{.*}})
+    char A[20];
+    return bar(A, 2);
+    // USE-AFTER-SCOPE: @llvm.lifetime.end(i64 20, i8* {{.*}})
+  }
+}
+