[compiler-rt] r349015 - [asan] Don't check ODR violations for particular types of globals

[Vitaly Buka via llvm-commits]

Author: vitalybuka
Date: Thu Dec 13 01:47:39 2018
New Revision: 349015

URL: http://llvm.org/viewvc/llvm-project?rev=349015&view=rev
Log:
[asan] Don't check ODR violations for particular types of globals

Summary:
private and internal: should not trigger ODR at all.
unnamed_addr: current ODR checking approach fail and rereport false violation if
a linker merges such globals
linkonce_odr, weak_odr: could cause similar problems and they are already not
instrumented for ELF.

Reviewers: eugenis, kcc

Subscribers: kubamracek, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D55621

Added:
    compiler-rt/trunk/test/asan/TestCases/Linux/odr_indicators.cc
Modified:
    compiler-rt/trunk/lib/asan/asan_globals.cc

Modified: compiler-rt/trunk/lib/asan/asan_globals.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_globals.cc?rev=349015&r1=349014&r2=349015&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_globals.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_globals.cc Thu Dec 13 01:47:39 2018
@@ -83,9 +83,11 @@ static bool IsAddressNearGlobal(uptr add
 }
 
 static void ReportGlobal(const Global &g, const char *prefix) {
-  Report("%s Global[%p]: beg=%p size=%zu/%zu name=%s module=%s dyn_init=%zu\n",
-         prefix, &g, (void *)g.beg, g.size, g.size_with_redzone, g.name,
-         g.module_name, g.has_dynamic_init);
+  Report(
+      "%s Global[%p]: beg=%p size=%zu/%zu name=%s module=%s dyn_init=%zu "
+      "odr_indicator=%p\n",
+      prefix, &g, (void *)g.beg, g.size, g.size_with_redzone, g.name,
+      g.module_name, g.has_dynamic_init, (void *)g.odr_indicator);
   if (g.location) {
     Report("  location (%p): name=%s[%p], %d %d\n", g.location,
            g.location->filename, g.location->filename, g.location->line_no,
@@ -133,6 +135,9 @@ enum GlobalSymbolState {
 // this method in case compiler instruments global variables through their
 // local aliases.
 static void CheckODRViolationViaIndicator(const Global *g) {
+  // Instrumentation requests to skip ODR check.
+  if (g->odr_indicator == UINTPTR_MAX)
+    return;
   u8 *odr_indicator = reinterpret_cast<u8 *>(g->odr_indicator);
   if (*odr_indicator == UNREGISTERED) {
     *odr_indicator = REGISTERED;
@@ -246,7 +251,7 @@ static void UnregisterGlobal(const Globa
   // implementation. It might not be worth doing anyway.
 
   // Release ODR indicator.
-  if (UseODRIndicator(g)) {
+  if (UseODRIndicator(g) && g->odr_indicator != UINTPTR_MAX) {
     u8 *odr_indicator = reinterpret_cast<u8 *>(g->odr_indicator);
     *odr_indicator = UNREGISTERED;
   }

Added: compiler-rt/trunk/test/asan/TestCases/Linux/odr_indicators.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Linux/odr_indicators.cc?rev=349015&view=auto
==============================================================================
--- compiler-rt/trunk/test/asan/TestCases/Linux/odr_indicators.cc (added)
+++ compiler-rt/trunk/test/asan/TestCases/Linux/odr_indicators.cc Thu Dec 13 01:47:39 2018
@@ -0,0 +1,26 @@
+// RUN: %clangxx_asan -fPIC %s -o %t
+// RUN: %env_asan_opts=report_globals=2 %run %t 2>&1 | FileCheck %s --check-prefixes=CHECK,INDICATOR0
+
+// RUN: %clangxx_asan -fsanitize-address-use-odr-indicator -fPIC %s -o %t
+// RUN: %env_asan_opts=report_globals=2 %run %t 2>&1 | FileCheck %s --check-prefixes=CHECK,INDICATOR1
+
+#include <stdio.h>
+
+int test_global_1;
+// INDICATOR0-DAG: Added Global{{.*}} name=test_global_1{{.*}} odr_indicator={{0x0+$}}
+// INDICATOR1-DAG: Added Global{{.*}} name=test_global_1{{.*}} odr_indicator={{0x0*[^0]+.*$}}
+
+static int test_global_2;
+// CHECK-DAG: Added Global{{.*}} name=test_global_2{{.*}} odr_indicator={{0xf+$}}
+
+namespace {
+static int test_global_3;
+// CHECK-DAG: Added Global{{.*}} name={{.*}}::test_global_3{{.*}} odr_indicator={{0xf+$}}
+} // namespace
+
+int main() {
+  const char f[] = "%d %d %d\n";
+  // CHECK-DAG: Added Global{{.*}} name=__const.main.f{{.*}} odr_indicator={{0xf+$}}
+  printf(f, test_global_1, test_global_2, test_global_3);
+  return 0;
+}