From 119046098a1b0a862b292c2937c5b625880a19ef Mon Sep 17 00:00:00 2001
From: Anna Zaks <ganna@apple.com>
Date: Tue, 9 Jun 2015 00:58:08 +0000
Subject: [PATCH] [asan] Prevent __attribute__((annotate)) triggering errors on
 Darwin

The following code triggers a fatal error in the compiler instrumentation
of ASan on Darwin because we place the attribute into llvm.metadata section,
which does not have the proper MachO section name.

void foo() __attribute__((annotate("custom")));
void foo() {;}

This commit reorders the checks so that we skip everything in llvm.metadata
first. It also removes the hard failure in case the section name does not
parse. That check will be done lower in the compilation pipeline anyway.

(Reviewed in http://reviews.llvm.org/D9093.)

llvm-svn: 239379
---
 .../Instrumentation/AddressSanitizer.cpp           | 28 +++++++++++-----------
 .../do-not-instrument-llvm-metadata-darwin.ll      | 12 ++++++++++
 2 files changed, 26 insertions(+), 14 deletions(-)
 create mode 100644 llvm/test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata-darwin.ll

diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 39c1e41..25f78b0 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -1133,6 +1133,18 @@ bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) {
   if (G->hasSection()) {
     StringRef Section(G->getSection());
 
+    // Globals from llvm.metadata aren't emitted, do not instrument them.
+    if (Section == "llvm.metadata") return false;
+
+    // Callbacks put into the CRT initializer/terminator sections
+    // should not be instrumented.
+    // See https://code.google.com/p/address-sanitizer/issues/detail?id=305
+    // and http://msdn.microsoft.com/en-US/en-en/library/bb918180(v=vs.120).aspx
+    if (Section.startswith(".CRT")) {
+      DEBUG(dbgs() << "Ignoring a global initializer callback: " << *G << "\n");
+      return false;
+    }
+
     if (TargetTriple.isOSBinFormatMachO()) {
       StringRef ParsedSegment, ParsedSection;
       unsigned TAA = 0, StubSize = 0;
@@ -1140,8 +1152,8 @@ bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) {
       std::string ErrorCode = MCSectionMachO::ParseSectionSpecifier(
           Section, ParsedSegment, ParsedSection, TAA, TAAParsed, StubSize);
       if (!ErrorCode.empty()) {
-        report_fatal_error("Invalid section specifier '" + ParsedSection +
-                           "': " + ErrorCode + ".");
+        assert(false && "Invalid section specifier.");
+        return false;
       }
 
       // Ignore the globals from the __OBJC section. The ObjC runtime assumes
@@ -1171,18 +1183,6 @@ bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) {
         return false;
       }
     }
-
-    // Callbacks put into the CRT initializer/terminator sections
-    // should not be instrumented.
-    // See https://code.google.com/p/address-sanitizer/issues/detail?id=305
-    // and http://msdn.microsoft.com/en-US/en-en/library/bb918180(v=vs.120).aspx
-    if (Section.startswith(".CRT")) {
-      DEBUG(dbgs() << "Ignoring a global initializer callback: " << *G << "\n");
-      return false;
-    }
-
-    // Globals from llvm.metadata aren't emitted, do not instrument them.
-    if (Section == "llvm.metadata") return false;
   }
 
   return true;
diff --git a/llvm/test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata-darwin.ll b/llvm/test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata-darwin.ll
new file mode 100644
index 0000000..7617dbd
--- /dev/null
+++ b/llvm/test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata-darwin.ll
@@ -0,0 +1,12 @@
+; This test checks that we are not instrumenting globals in llvm.metadata.
+; RUN: opt < %s -asan -asan-module -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.10.0"
+
+@.str_noinst = private unnamed_addr constant [4 x i8] c"aaa\00", section "llvm.metadata"
+@.str_inst = private unnamed_addr constant [4 x i8] c"aaa\00"
+
+; CHECK-NOT: {{asan_gen.*str_noinst}}
+; CHECK: {{asan_gen.*str_inst}}
+; CHECK: @asan.module_ctor
-- 
2.7.4