[llvm] r218421 - [asan] don't instrument module CTORs that may be run before asan.module_ctor. This fixes asan running together -coverage

[Kostya Serebryany]

Author: kcc
Date: Wed Sep 24 17:41:55 2014
New Revision: 218421

URL: http://llvm.org/viewvc/llvm-project?rev=218421&view=rev
Log:
[asan] don't instrument module CTORs that may be run before asan.module_ctor. This fixes asan running together -coverage 

Modified:
    llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
    llvm/trunk/test/Instrumentation/AddressSanitizer/instrument_initializer_metadata.ll

Modified: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp?rev=218421&r1=218420&r2=218421&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp Wed Sep 24 17:41:55 2014
@@ -71,7 +71,7 @@ static const uintptr_t kRetiredStackFram
 
 static const char *const kAsanModuleCtorName = "asan.module_ctor";
 static const char *const kAsanModuleDtorName = "asan.module_dtor";
-static const int         kAsanCtorAndDtorPriority = 1;
+static const uint64_t    kAsanCtorAndDtorPriority = 1;
 static const char *const kAsanReportErrorTemplate = "__asan_report_";
 static const char *const kAsanReportLoadN = "__asan_report_load_n";
 static const char *const kAsanReportStoreN = "__asan_report_store_n";
@@ -928,10 +928,12 @@ void AddressSanitizerModule::createIniti
     ConstantStruct *CS = cast<ConstantStruct>(OP);
 
     // Must have a function or null ptr.
-    // (CS->getOperand(0) is the init priority.)
     if (Function* F = dyn_cast<Function>(CS->getOperand(1))) {
-      if (F->getName() != kAsanModuleCtorName)
-        poisonOneInitializer(*F, ModuleName);
+      if (F->getName() == kAsanModuleCtorName) continue;
+      ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
+      // Don't instrument CTORs that will run before asan.module_ctor.
+      if (Priority->getLimitedValue() <= kAsanCtorAndDtorPriority) continue;
+      poisonOneInitializer(*F, ModuleName);
     }
   }
 }

Modified: llvm/trunk/test/Instrumentation/AddressSanitizer/instrument_initializer_metadata.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/AddressSanitizer/instrument_initializer_metadata.ll?rev=218421&r1=218420&r2=218421&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/AddressSanitizer/instrument_initializer_metadata.ll (original)
+++ llvm/trunk/test/Instrumentation/AddressSanitizer/instrument_initializer_metadata.ll Wed Sep 24 17:41:55 2014
@@ -25,29 +25,39 @@ entry:
   ret void
 }
 
- at llvm.global_ctors = appending global [1 x { i32, void ()* }] [{ i32, void ()* } { i32 65535, void ()* @_GLOBAL__I_a }]
+ at llvm.global_ctors = appending global [2 x { i32, void ()* }] [{ i32, void ()* } { i32 65535, void ()* @__late_ctor }, { i32, void ()* } { i32 0, void ()* @__early_ctor }]
 
-define internal void @_GLOBAL__I_a() sanitize_address section ".text.startup" {
+define internal void @__late_ctor() sanitize_address section ".text.startup" {
 entry:
   call void @__cxx_global_var_init()
   ret void
 }
 
 ; Clang indicated that @xxx was dynamically initailized.
-; __asan_{before,after}_dynamic_init should be called from _GLOBAL__I_a
+; __asan_{before,after}_dynamic_init should be called from __late_ctor
 
-; CHECK: define internal void @_GLOBAL__I_a
+; CHECK-LABEL: define internal void @__late_ctor
 ; CHECK-NOT: ret
 ; CHECK: call void @__asan_before_dynamic_init
 ; CHECK: call void @__cxx_global_var_init
 ; CHECK: call void @__asan_after_dynamic_init
 ; CHECK: ret
 
+; CTOR with priority 0 should not be instrumented.
+define internal void @__early_ctor() sanitize_address section ".text.startup" {
+entry:
+  call void @__cxx_global_var_init()
+  ret void
+}
+; CHECK-LABEL: define internal void @__early_ctor
+; CHECK-NOT: __asan
+; CHECK: ret
+
 ; Check that xxx is instrumented.
 define void @touch_xxx() sanitize_address {
   store i32 0, i32 *@xxx, align 4
   ret void
-; CHECK: define void @touch_xxx
+; CHECK-LABEL: touch_xxx
 ; CHECK: call void @__asan_report_store4
 ; CHECK: ret void
 }