r212188 - [ASan] Print exact source location of global variables in error reports.
Alexey Samsonov
vonosmas at gmail.com
Wed Jul 2 09:54:42 PDT 2014
Author: samsonov
Date: Wed Jul 2 11:54:41 2014
New Revision: 212188
URL: http://llvm.org/viewvc/llvm-project?rev=212188&view=rev
Log:
[ASan] Print exact source location of global variables in error reports.
See https://code.google.com/p/address-sanitizer/issues/detail?id=299 for the
original feature request.
Introduce llvm.asan.globals metadata, which Clang (or any other frontend)
may use to report extra information about global variables to ASan
instrumentation pass in the backend. This metadata replaces
llvm.asan.dynamically_initialized_globals that was used to detect init-order
bugs. llvm.asan.globals contains the following data for each global:
1) source location (file/line/column info);
2) whether it is dynamically initialized;
3) whether it is blacklisted (shouldn't be instrumented).
Source location data is then emitted in the binary and can be picked up
by ASan runtime in case it needs to print error report involving some global.
For example:
0x... is located 4 bytes to the right of global variable 'C::array' defined in '/path/to/file:17:8' (0x...) of size 40
These source locations are printed even if the binary doesn't have any
debug info.
This is an ABI-breaking change. ASan initialization is renamed to
__asan_init_v4(). Pre-built libraries compiled with older Clang will not work
with the fresh runtime.
Added:
cfe/trunk/test/CodeGen/asan-globals.cpp
Modified:
cfe/trunk/lib/CodeGen/CGDecl.cpp
cfe/trunk/lib/CodeGen/CodeGenModule.cpp
cfe/trunk/lib/CodeGen/CodeGenModule.h
cfe/trunk/test/CodeGen/sanitize-init-order.cpp
Modified: cfe/trunk/lib/CodeGen/CGDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDecl.cpp?rev=212188&r1=212187&r2=212188&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGDecl.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGDecl.cpp Wed Jul 2 11:54:41 2014
@@ -345,6 +345,8 @@ void CodeGenFunction::EmitStaticVarDecl(
DMEntry = castedAddr;
CGM.setStaticLocalDeclAddress(&D, castedAddr);
+ CGM.reportGlobalToASan(var, D.getLocation());
+
// Emit global variable debug descriptor for static vars.
CGDebugInfo *DI = getDebugInfo();
if (DI &&
Modified: cfe/trunk/lib/CodeGen/CodeGenModule.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.cpp?rev=212188&r1=212187&r2=212188&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenModule.cpp (original)
+++ cfe/trunk/lib/CodeGen/CodeGenModule.cpp Wed Jul 2 11:54:41 2014
@@ -1958,16 +1958,7 @@ void CodeGenModule::EmitGlobalVarDefinit
if (NeedsGlobalCtor || NeedsGlobalDtor)
EmitCXXGlobalVarDeclInitFunc(D, GV, NeedsGlobalCtor);
- // If we are compiling with ASan, add metadata indicating dynamically
- // initialized (and not blacklisted) globals.
- if (SanOpts.Address && NeedsGlobalCtor &&
- !SanitizerBlacklist->isIn(*GV, "init")) {
- llvm::NamedMDNode *DynamicInitializers = TheModule.getOrInsertNamedMetadata(
- "llvm.asan.dynamically_initialized_globals");
- llvm::Value *GlobalToAdd[] = { GV };
- llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalToAdd);
- DynamicInitializers->addOperand(ThisGlobal);
- }
+ reportGlobalToASan(GV, D->getLocation(), NeedsGlobalCtor);
// Emit global variable debug information.
if (CGDebugInfo *DI = getModuleDebugInfo())
@@ -1975,6 +1966,51 @@ void CodeGenModule::EmitGlobalVarDefinit
DI->EmitGlobalVariable(GV, D);
}
+void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
+ SourceLocation Loc, bool IsDynInit) {
+ if (!SanOpts.Address)
+ return;
+ IsDynInit &= !SanitizerBlacklist->isIn(*GV, "init");
+ bool IsBlacklisted = SanitizerBlacklist->isIn(*GV);
+
+ llvm::LLVMContext &LLVMCtx = TheModule.getContext();
+
+ llvm::GlobalVariable *LocDescr = nullptr;
+ if (!IsBlacklisted) {
+ // Don't generate source location if a global is blacklisted - it won't
+ // be instrumented anyway.
+ PresumedLoc PLoc = Context.getSourceManager().getPresumedLoc(Loc);
+ if (PLoc.isValid()) {
+ llvm::Constant *LocData[] = {
+ GetAddrOfConstantCString(PLoc.getFilename()),
+ llvm::ConstantInt::get(llvm::Type::getInt32Ty(LLVMCtx), PLoc.getLine()),
+ llvm::ConstantInt::get(llvm::Type::getInt32Ty(LLVMCtx),
+ PLoc.getColumn()),
+ };
+ auto LocStruct = llvm::ConstantStruct::getAnon(LocData);
+ LocDescr = new llvm::GlobalVariable(TheModule, LocStruct->getType(), true,
+ llvm::GlobalValue::PrivateLinkage,
+ LocStruct, ".asan_loc_descr");
+ LocDescr->setUnnamedAddr(true);
+ // Add LocDescr to llvm.compiler.used, so that it won't be removed by
+ // the optimizer before the ASan instrumentation pass.
+ addCompilerUsedGlobal(LocDescr);
+ }
+ }
+
+ llvm::Value *GlobalMetadata[] = {
+ GV,
+ LocDescr,
+ llvm::ConstantInt::get(llvm::Type::getInt1Ty(LLVMCtx), IsDynInit),
+ llvm::ConstantInt::get(llvm::Type::getInt1Ty(LLVMCtx), IsBlacklisted)
+ };
+
+ llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata);
+ llvm::NamedMDNode *AsanGlobals =
+ TheModule.getOrInsertNamedMetadata("llvm.asan.globals");
+ AsanGlobals->addOperand(ThisGlobal);
+}
+
static bool isVarDeclStrongDefinition(const VarDecl *D, bool NoCommon) {
// Don't give variables common linkage if -fno-common was specified unless it
// was overridden by a NoCommon attribute.
@@ -2779,6 +2815,8 @@ CodeGenModule::GetAddrOfConstantStringFr
auto GV = GenerateStringLiteral(C, LT, *this, GlobalVariableName, Alignment);
if (Entry)
Entry->setValue(GV);
+
+ reportGlobalToASan(GV, S->getStrTokenLoc(0));
return GV;
}
Modified: cfe/trunk/lib/CodeGen/CodeGenModule.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.h?rev=212188&r1=212187&r2=212188&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenModule.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenModule.h Wed Jul 2 11:54:41 2014
@@ -1025,6 +1025,9 @@ public:
const SanitizerOptions &getSanOpts() const { return SanOpts; }
+ void reportGlobalToASan(llvm::GlobalVariable *GV, SourceLocation Loc,
+ bool IsDynInit = false);
+
void addDeferredVTable(const CXXRecordDecl *RD) {
DeferredVTables.push_back(RD);
}
Added: cfe/trunk/test/CodeGen/asan-globals.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/asan-globals.cpp?rev=212188&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/asan-globals.cpp (added)
+++ cfe/trunk/test/CodeGen/asan-globals.cpp Wed Jul 2 11:54:41 2014
@@ -0,0 +1,23 @@
+// RUN: echo "global:*blacklisted_global*" > %t.blacklist
+// RUN: %clang_cc1 -fsanitize=address -fsanitize-blacklist=%t.blacklist -emit-llvm -o - %s | FileCheck %s
+// REQUIRES: shell
+
+int global;
+// CHECK: [[GLOBAL_LOC:@.asan_loc_descr[0-9]*]] = private unnamed_addr constant {{.*}} i32 [[@LINE-1]], i32 5
+int dyn_init_global = global;
+// CHECK: [[DYN_INIT_LOC:@.asan_loc_descr[0-9]*]] = {{.*}} i32 [[@LINE-1]], i32 5
+int blacklisted_global;
+
+void func() {
+ static int static_var = 0;
+ // CHECK: [[STATIC_LOC:@.asan_loc_descr[0-9]*]] = {{.*}} i32 [[@LINE-1]], i32 14
+ const char *literal = "Hello, world!";
+ // CHECK: [[LITERAL_LOC:@.asan_loc_descr[0-9]*]] = {{.*}} i32 [[@LINE-1]], i32 25
+}
+
+// CHECK: !llvm.asan.globals = !{![[GLOBAL:[0-9]+]], ![[DYN_INIT_GLOBAL:[0-9]+]], ![[BLACKLISTED_GLOBAL:[0-9]+]], ![[STATIC_VAR:[0-9]+]], ![[LITERAL:[0-9]+]]}
+// CHECK: ![[GLOBAL]] = metadata !{{{.*}} [[GLOBAL_LOC]], i1 false, i1 false}
+// CHECK: ![[DYN_INIT_GLOBAL]] = metadata !{{{.*}} [[DYN_INIT_LOC]], i1 true, i1 false}
+// CHECK: ![[BLACKLISTED_GLOBAL]] = metadata !{{{.*}}, null, i1 false, i1 true}
+// CHECK: ![[STATIC_VAR]] = metadata !{{{.*}} [[STATIC_LOC]], i1 false, i1 false}
+// CHECK: ![[LITERAL]] = metadata !{{{.*}} [[LITERAL_LOC]], i1 false, i1 false}
Modified: cfe/trunk/test/CodeGen/sanitize-init-order.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/sanitize-init-order.cpp?rev=212188&r1=212187&r2=212188&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/sanitize-init-order.cpp (original)
+++ cfe/trunk/test/CodeGen/sanitize-init-order.cpp Wed Jul 2 11:54:41 2014
@@ -27,7 +27,12 @@ PODWithCtorAndDtor s3;
// Check that ASan init-order checking ignores structs with trivial default
// constructor.
-// CHECK: !llvm.asan.dynamically_initialized_globals = !{[[GLOB:![0-9]+]]}
-// CHECK: [[GLOB]] = metadata !{%struct.PODWithCtorAndDtor
+// CHECK: !llvm.asan.globals = !{![[GLOB_1:[0-9]+]], ![[GLOB_2:[0-9]+]], ![[GLOB_3:[0-9]]]}
+// CHECK: ![[GLOB_1]] = metadata !{%struct.PODStruct* {{.*}}, i1 false, i1 false}
+// CHECK: ![[GLOB_2]] = metadata !{%struct.PODWithDtor* {{.*}}, i1 false, i1 false}
+// CHECK: ![[GLOB_3]] = metadata !{%struct.PODWithCtorAndDtor* {{.*}}, i1 true, i1 false}
-// BLACKLIST-NOT: llvm.asan.dynamically_initialized_globals
+// BLACKLIST: !llvm.asan.globals = !{![[GLOB_1:[0-9]+]], ![[GLOB_2:[0-9]+]], ![[GLOB_3:[0-9]]]}
+// BLACKLIST: ![[GLOB_1]] = metadata !{%struct.PODStruct* {{.*}}, i1 false, i1 false}
+// BLACKLIST: ![[GLOB_2]] = metadata !{%struct.PODWithDtor* {{.*}}, i1 false, i1 false}
+// BLACKLIST: ![[GLOB_3]] = metadata !{%struct.PODWithCtorAndDtor* {{.*}}, i1 false, i1 false}
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