From: Vedant Kumar <vsk@apple.com>
Date: Mon, 8 May 2017 21:11:55 +0000 (+0000)
Subject: [Driver] Don't enable -fsanitize-use-after-scope when ASan is disabled
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=45e72552c72e15179e1806634023d112cec95dbb;p=clang

[Driver] Don't enable -fsanitize-use-after-scope when ASan is disabled

When enabling any sanitizer, -fsanitize-use-after-scope is enabled by
default. This doesn't actually turn ASan on, because we've been getting
lucky and there are extra checks in BackendUtil that stop this from
happening.

However, this has been causing a behavior change: extra lifetime markers
are emitted in some cases where they aren't needed or expected.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@302468 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Driver/SanitizerArgs.cpp b/lib/Driver/SanitizerArgs.cpp
index c298302c47..b1f5f860d4 100644
--- a/lib/Driver/SanitizerArgs.cpp
+++ b/lib/Driver/SanitizerArgs.cpp
@@ -563,12 +563,11 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
       }
     }
 
-    if (Arg *A = Args.getLastArg(
-            options::OPT_fsanitize_address_use_after_scope,
-            options::OPT_fno_sanitize_address_use_after_scope)) {
-      AsanUseAfterScope = A->getOption().getID() ==
-                          options::OPT_fsanitize_address_use_after_scope;
-    }
+    AsanUseAfterScope = Args.hasFlag(
+        options::OPT_fsanitize_address_use_after_scope,
+        options::OPT_fno_sanitize_address_use_after_scope, AsanUseAfterScope);
+  } else {
+    AsanUseAfterScope = false;
   }
 
   // Parse -link-cxx-sanitizer flag.
diff --git a/test/Driver/fsanitize.c b/test/Driver/fsanitize.c
index 05e239c742..bce55ac065 100644
--- a/test/Driver/fsanitize.c
+++ b/test/Driver/fsanitize.c
@@ -30,7 +30,7 @@
 // RUN: %clang -target x86_64-pc-win32 -fsanitize-coverage=bb %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-COVERAGE-WIN64
 // CHECK-COVERAGE-WIN64: "--dependent-lib={{[^"]*}}ubsan_standalone-x86_64.lib"
 
-// RUN: %clang -target x86_64-linux-gnu -fsanitize=integer %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-INTEGER
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=integer %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-INTEGER -implicit-check-not="-fsanitize-address-use-after-scope"
 // CHECK-INTEGER: "-fsanitize={{((signed-integer-overflow|unsigned-integer-overflow|integer-divide-by-zero|shift-base|shift-exponent),?){5}"}}
 
 // RUN: %clang -fsanitize=bounds -### -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix=CHECK-BOUNDS