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Change the linkage of these global values to 'internal'.

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The globals being generated here were given the 'private' linkage type. However,
this caused them to end up in different sections with the wrong prefix. E.g.,
they would be in the __TEXT,__const section with an 'L' prefix instead of an 'l'
(lowercase ell) prefix.

The problem is that the linker will eat a literal label with 'L'. If a weak
symbol is then placed into the __TEXT,__const section near that literal, then it
cannot distinguish between the literal and the weak symbol.

Part of the problems here was introduced because the address sanitizer converted
some C strings into constant initializers with trailing nuls. (Thus putting them
in the __const section with the wrong prefix.) The others were variables that
the address sanitizer created but simply had the wrong linkage type.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187827 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2013-08-06 22:52:42 +00:00
parent 47cfec0284
commit 55a1a590bf
2 changed files with 9 additions and 6 deletions
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11
lib/Transforms/Instrumentation/AddressSanitizer.cpp
View File

@ -547,11 +547,11 @@ static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
return Res;
}
// Create a constant for Str so that we can pass it to the run-time lib.
// \brief Create a constant for Str so that we can pass it to the run-time lib.
static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
GlobalVariable *GV = new GlobalVariable(M, StrConst->getType(), true,
GlobalValue::PrivateLinkage, StrConst,
GlobalValue::InternalLinkage, StrConst,
kAsanGenPrefix);
GV->setUnnamedAddr(true); // Ok to merge these.
GV->setAlignment(1); // Strings may not be merged w/o setting align 1.
@ -961,8 +961,11 @@ bool AddressSanitizerModule::runOnModule(Module &M) {
GlobalVariable *Name = createPrivateGlobalForString(M, G->getName());
// Create a new global variable with enough space for a redzone.
GlobalValue::LinkageTypes Linkage = G->getLinkage();
if (G->isConstant() && Linkage == GlobalValue::PrivateLinkage)
Linkage = GlobalValue::InternalLinkage;
GlobalVariable *NewGlobal = new GlobalVariable(
M, NewTy, G->isConstant(), G->getLinkage(),
M, NewTy, G->isConstant(), Linkage,
NewInitializer, "", G, G->getThreadLocalMode());
NewGlobal->copyAttributesFrom(G);
NewGlobal->setAlignment(MinRZ);
@ -995,7 +998,7 @@ bool AddressSanitizerModule::runOnModule(Module &M) {
ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
GlobalVariable *AllGlobals = new GlobalVariable(
M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage,
M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage,
ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
// Create calls for poisoning before initializers run and unpoisoning after.

4
test/Instrumentation/AddressSanitizer/do-not-instrument-internal-globals.ll
View File

@ -16,5 +16,5 @@ declare void @_Z3fooPi(i32*)
; We create one global string constant for the stack frame above.
; It should have unnamed_addr and align 1.
; Make sure we don't create any other global constants.
; CHECK: = private unnamed_addr constant{{.*}}align 1
; CHECK-NOT: = private unnamed_addr constant
; CHECK: = internal unnamed_addr constant{{.*}}align 1
; CHECK-NOT: = internal unnamed_addr constant