replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

[ASan] Make sure none of the __asan_gen_ global strings end up in the symbol table, add a test. 

This should fix http://llvm.org/bugs/show_bug.cgi?id=17976
Another test checking for the global variables' locations and prefixes on Darwin will be committed separately.

llvm-svn: 198017
This commit is contained in:
Alexander Potapenko 2013-12-25 14:22:15 +00:00
parent 208915b5ea
commit daf96ae81b
2 changed files with 28 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
compiler-rt/lib/asan/lit_tests/TestCases/no_asan_gen_globals.c Normal file
View File

@ -0,0 +1,7 @@
// Make sure __asan_gen_* strings do not end up in the symbol table.
// RUN: %clang_asan %s -o %t.exe
// RUN: nm %t.exe | grep __asan_gen_ || exit 0
int x, y, z;
int main() { return 0; }

31
llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
View File

@ -558,12 +558,22 @@ static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
}
// \brief Create a constant for Str so that we can pass it to the run-time lib.
static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
static GlobalVariable *createPrivateGlobalForString(
Module &M, StringRef Str, bool AllowMerging) {
Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
GlobalVariable *GV = new GlobalVariable(M, StrConst->getType(), true,
GlobalValue::InternalLinkage, StrConst,
kAsanGenPrefix);
GV->setUnnamedAddr(true); // Ok to merge these.
// For module-local strings that can be merged with another one we set the
// internal linkage and the unnamed_addr attribute.
// Non-mergeable strings are made linker_private to remove them from the
// symbol table. "private" linkage doesn't work for Darwin, where the
// "L"-prefixed globals end up in __TEXT,__const section
// (see http://llvm.org/bugs/show_bug.cgi?id=17976 for more info).
GlobalValue::LinkageTypes linkage =
AllowMerging ? GlobalValue::InternalLinkage
: GlobalValue::LinkerPrivateLinkage;
GlobalVariable *GV =
new GlobalVariable(M, StrConst->getType(), true,
linkage, StrConst, kAsanGenPrefix);
if (AllowMerging) GV->setUnnamedAddr(true);
GV->setAlignment(1); // Strings may not be merged w/o setting align 1.
return GV;
}
@ -950,11 +960,10 @@ bool AddressSanitizerModule::runOnModule(Module &M) {
bool HasDynamicallyInitializedGlobals = false;
GlobalVariable *ModuleName = createPrivateGlobalForString(
M, M.getModuleIdentifier());
// We shouldn't merge same module names, as this string serves as unique
// module ID in runtime.
ModuleName->setUnnamedAddr(false);
GlobalVariable *ModuleName = createPrivateGlobalForString(
M, M.getModuleIdentifier(), /*AllowMerging*/false);
for (size_t i = 0; i < n; i++) {
static const uint64_t kMaxGlobalRedzone = 1 << 18;
@ -985,7 +994,8 @@ bool AddressSanitizerModule::runOnModule(Module &M) {
NewTy, G->getInitializer(),
Constant::getNullValue(RightRedZoneTy), NULL);
GlobalVariable *Name = createPrivateGlobalForString(M, G->getName());
GlobalVariable *Name =
createPrivateGlobalForString(M, G->getName(), /*AllowMerging*/true);
// Create a new global variable with enough space for a redzone.
GlobalValue::LinkageTypes Linkage = G->getLinkage();
@ -1493,7 +1503,8 @@ void FunctionStackPoisoner::poisonStack() {
IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, ASan.LongSize/8)),
IntptrPtrTy);
GlobalVariable *StackDescriptionGlobal =
createPrivateGlobalForString(*F.getParent(), L.DescriptionString);
createPrivateGlobalForString(*F.getParent(), L.DescriptionString,
/*AllowMerging*/true);
Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal,
IntptrTy);
IRB.CreateStore(Description, BasePlus1);