[PATCH] [asan] Do not instrument globals from special purpose llvm sections

[Anna Zaks]

Hi kcc, bob.wilson,

Do not instrument globals that are placed in sections containing "__llvm" in their name.

ASan interferes with LLVM's PGO, which places its globals into a special section, which is memcpy-ed by the linker as a whole. When those goals are instrumented, ASan's memcpy wrapper reports an issue.

http://reviews.llvm.org/D10541

Files:
  lib/Transforms/Instrumentation/AddressSanitizer.cpp
  test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata-darwin.ll
  test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata.ll

Index: lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -1142,6 +1142,8 @@
 
     // Globals from llvm.metadata aren't emitted, do not instrument them.
     if (Section == "llvm.metadata") return false;
+    // Do not instrument globals from special llvm sections.
+    if (Section.find("__llvm") != StringRef::npos) return false;
 
     // Callbacks put into the CRT initializer/terminator sections
     // should not be instrumented.
Index: test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata-darwin.ll
===================================================================
--- test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata-darwin.ll
+++ test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata-darwin.ll
@@ -1,12 +1,15 @@
-; This test checks that we are not instrumenting globals in llvm.metadata.
+; This test checks that we are not instrumenting globals in llvm.metadata
+; and other llvm internal globals.
 ; 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"
+ at .str_noinst_prof = private unnamed_addr constant [4 x i8] c"aaa\00", section "__DATA,__llvm_covmap"
 @.str_inst = private unnamed_addr constant [4 x i8] c"aaa\00"
 
 ; CHECK-NOT: {{asan_gen.*str_noinst}}
+; CHECK-NOT: {{asan_gen.*str_noinst_prof}}
 ; CHECK: {{asan_gen.*str_inst}}
 ; CHECK: @asan.module_ctor
Index: test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata.ll
===================================================================
--- test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata.ll
+++ test/Instrumentation/AddressSanitizer/do-not-instrument-llvm-metadata.ll
@@ -1,12 +1,15 @@
-; This test checks that we are not instrumenting globals in llvm.metadata.
+; This test checks that we are not instrumenting globals in llvm.metadata
+; and other llvm internal globals.
 ; 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-unknown-linux-gnu"
 
 @.str_noinst = private unnamed_addr constant [4 x i8] c"aaa\00", section "llvm.metadata"
+ at .str_noinst_prof = private unnamed_addr constant [4 x i8] c"aaa\00", section "__llvm_prf_data"
 @.str_inst = private unnamed_addr constant [4 x i8] c"aaa\00"
 
 ; CHECK-NOT: {{asan_gen.*str_noinst}}
+; CHECK-NOT: {{asan_gen.*str_noinst_prof}}
 ; CHECK: {{asan_gen.*str_inst}}
 ; CHECK: @asan.module_ctor

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