[ASan] Collect unmangled names of global variables in Clang to print them in error...

Currently ASan instrumentation pass creates a string with global name
for each instrumented global (to include global names in the error report). Global
name is already mangled at this point, and we may not be able to demangle it
at runtime (e.g. there is no __cxa_demangle on Android).

Instead, create a string with fully qualified global name in Clang, and pass it
to ASan instrumentation pass in llvm.asan.globals metadata. If there is no metadata
for some global, ASan will use the original algorithm.

This fixes https://code.google.com/p/address-sanitizer/issues/detail?id=264.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212872 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index 9bd61d7164f5811d9db31a396ee5e341e05929fc..91f804193049eda1f50dcb386de6b2e0f3e36cb9 100644 (file)
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -345,7 +345,7 @@ void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D,
   DMEntry = castedAddr;
   CGM.setStaticLocalDeclAddress(&D, castedAddr);
 
-  CGM.reportGlobalToASan(var, D.getLocation());
+  CGM.reportGlobalToASan(var, D);
 
   // Emit global variable debug descriptor for static vars.
   CGDebugInfo *DI = getDebugInfo();

diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 2f87392c36043b78851cddd302bfbe03cd5e7cea..66ac524f2b9a32d1c008102287ea2935253d046d 100644 (file)
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -1952,7 +1952,7 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
   if (NeedsGlobalCtor || NeedsGlobalDtor)
     EmitCXXGlobalVarDeclInitFunc(D, GV, NeedsGlobalCtor);
 
-  reportGlobalToASan(GV, D->getLocation(), NeedsGlobalCtor);
+  reportGlobalToASan(GV, *D, NeedsGlobalCtor);
 
   // Emit global variable debug information.
   if (CGDebugInfo *DI = getModuleDebugInfo())
@@ -1961,24 +1961,25 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
 }
 
 void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
-                                       SourceLocation Loc, bool IsDynInit) {
+                                       SourceLocation Loc, StringRef Name,
+                                       bool IsDynInit) {
   if (!LangOpts.Sanitize.Address)
     return;
   IsDynInit &= !SanitizerBL.isIn(*GV, "init");
   bool IsBlacklisted = SanitizerBL.isIn(*GV);
 
-  llvm::LLVMContext &LLVMCtx = TheModule.getContext();
-
   llvm::GlobalVariable *LocDescr = nullptr;
+  llvm::GlobalVariable *GlobalName = nullptr;
   if (!IsBlacklisted) {
-    // Don't generate source location if a global is blacklisted - it won't
-    // be instrumented anyway.
+    // Don't generate source location and global name if it 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),
+          llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
+                                 PLoc.getLine()),
+          llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
                                  PLoc.getColumn()),
       };
       auto LocStruct = llvm::ConstantStruct::getAnon(LocData);
@@ -1990,14 +1991,17 @@ void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
       // the optimizer before the ASan instrumentation pass.
       addCompilerUsedGlobal(LocDescr);
     }
+    if (!Name.empty()) {
+      GlobalName = GetAddrOfConstantCString(Name);
+      // GlobalName shouldn't be removed by the optimizer.
+      addCompilerUsedGlobal(GlobalName);
+    }
   }
 
   llvm::Value *GlobalMetadata[] = {
-      GV,
-      LocDescr,
-      llvm::ConstantInt::get(llvm::Type::getInt1Ty(LLVMCtx), IsDynInit),
-      llvm::ConstantInt::get(llvm::Type::getInt1Ty(LLVMCtx), IsBlacklisted)
-  };
+      GV, LocDescr, GlobalName,
+      llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit),
+      llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsBlacklisted)};
 
   llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata);
   llvm::NamedMDNode *AsanGlobals =
@@ -2005,6 +2009,16 @@ void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
   AsanGlobals->addOperand(ThisGlobal);
 }
 
+void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
+                                       const VarDecl &D, bool IsDynInit) {
+  if (!LangOpts.Sanitize.Address)
+    return;
+  std::string QualName;
+  llvm::raw_string_ostream OS(QualName);
+  D.printQualifiedName(OS);
+  reportGlobalToASan(GV, D.getLocation(), OS.str(), IsDynInit);
+}
+
 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.
@@ -2810,7 +2824,7 @@ CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) {
   if (Entry)
     Entry->setValue(GV);
 
-  reportGlobalToASan(GV, S->getStrTokenLoc(0));
+  reportGlobalToASan(GV, S->getStrTokenLoc(0), "<string literal>");
   return GV;
 }
 

diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 342546974675eb52ee22937196287a4274eb7da1..d6b694a8824668958ad1da30b59ef8c6b62fc72a 100644 (file)
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -1015,8 +1015,10 @@ public:
     return SanitizerBL;
   }
 
-  void reportGlobalToASan(llvm::GlobalVariable *GV, SourceLocation Loc,
+  void reportGlobalToASan(llvm::GlobalVariable *GV, const VarDecl &D,
                           bool IsDynInit = false);
+  void reportGlobalToASan(llvm::GlobalVariable *GV, SourceLocation Loc,
+                          StringRef Name, bool IsDynInit = false);
 
   void addDeferredVTable(const CXXRecordDecl *RD) {
     DeferredVTables.push_back(RD);

diff --git a/test/CodeGen/asan-globals.cpp b/test/CodeGen/asan-globals.cpp
index 2702f1d450035a7b628e6ba5509427d35784b012..d9ecc64615421189cf1700a0933b1c3afd65c30e 100644 (file)
--- a/test/CodeGen/asan-globals.cpp
+++ b/test/CodeGen/asan-globals.cpp
@@ -6,27 +6,31 @@
 
 int global;
 // CHECK: [[GLOBAL_LOC:@.asan_loc_descr[0-9]*]] = private unnamed_addr constant {{.*}} i32 [[@LINE-1]], i32 5
+// CHECK: [[GLOBAL_NAME:@.str[0-9]+]] = private unnamed_addr constant {{.*}} c"global\00"
 int dyn_init_global = global;
 // CHECK: [[DYN_INIT_LOC:@.asan_loc_descr[0-9]*]] = {{.*}} i32 [[@LINE-1]], i32 5
+// CHECK: [[DYN_INIT_NAME:@.str[0-9]+]] = private unnamed_addr constant {{.*}} c"dyn_init_global\00"
 int blacklisted_global;
 
 void func() {
   static int static_var = 0;
   // CHECK: [[STATIC_LOC:@.asan_loc_descr[0-9]*]] = {{.*}} i32 [[@LINE-1]], i32 14
+  // CHECK: [[STATIC_NAME:@.str[0-9]+]] = private unnamed_addr constant {{.*}} c"static_var\00"
   const char *literal = "Hello, world!";
   // CHECK: [[LITERAL_LOC:@.asan_loc_descr[0-9]*]] = {{.*}} i32 [[@LINE-1]], i32 25
+  // CHECK: [[LITERAL_NAME:@.str[0-9]+]] = private unnamed_addr constant {{.*}} c"<string literal>\00"
 }
 
 // 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}
+// CHECK: ![[GLOBAL]] = metadata !{{{.*}} [[GLOBAL_LOC]], {{.*}} [[GLOBAL_NAME]], i1 false, i1 false}
+// CHECK: ![[DYN_INIT_GLOBAL]] = metadata !{{{.*}} [[DYN_INIT_LOC]], {{.*}} [[DYN_INIT_NAME]], i1 true, i1 false}
+// CHECK: ![[BLACKLISTED_GLOBAL]] = metadata !{{{.*}}, null, null, i1 false, i1 true}
+// CHECK: ![[STATIC_VAR]] = metadata !{{{.*}} [[STATIC_LOC]], {{.*}} [[STATIC_NAME]], i1 false, i1 false}
+// CHECK: ![[LITERAL]] = metadata !{{{.*}} [[LITERAL_LOC]], {{.*}} [[LITERAL_NAME]], i1 false, i1 false}
 
 // BLACKLIST-SRC: !llvm.asan.globals = !{![[GLOBAL:[0-9]+]], ![[DYN_INIT_GLOBAL:[0-9]+]], ![[BLACKLISTED_GLOBAL:[0-9]+]], ![[STATIC_VAR:[0-9]+]], ![[LITERAL:[0-9]+]]}
-// BLACKLIST-SRC: ![[GLOBAL]] = metadata !{{{.*}} null, i1 false, i1 true}
-// BLACKLIST-SRC: ![[DYN_INIT_GLOBAL]] = metadata !{{{.*}} null, i1 true, i1 true}
-// BLACKLIST-SRC: ![[BLACKLISTED_GLOBAL]] = metadata !{{{.*}}, null, i1 false, i1 true}
-// BLACKLIST-SRC: ![[STATIC_VAR]] = metadata !{{{.*}} null, i1 false, i1 true}
-// BLACKLIST-SRC: ![[LITERAL]] = metadata !{{{.*}} null, i1 false, i1 true}
+// BLACKLIST-SRC: ![[GLOBAL]] = metadata !{{{.*}} null, null, i1 false, i1 true}
+// BLACKLIST-SRC: ![[DYN_INIT_GLOBAL]] = metadata !{{{.*}} null, null, i1 true, i1 true}
+// BLACKLIST-SRC: ![[BLACKLISTED_GLOBAL]] = metadata !{{{.*}}, null, null, i1 false, i1 true}
+// BLACKLIST-SRC: ![[STATIC_VAR]] = metadata !{{{.*}} null, null, i1 false, i1 true}
+// BLACKLIST-SRC: ![[LITERAL]] = metadata !{{{.*}} null, null, i1 false, i1 true}