[sanitizers] Disable target-specific lowering of string functions.
CodeGen has hooks that allow targets to emit specialized code instead
of calls to memcmp, memchr, strcpy, stpcpy, strcmp, strlen, strnlen.
When ASan/MSan/TSan/ESan is in use, this sidesteps its interceptors, resulting
in uninstrumented memory accesses. To avoid that, make these sanitizers
mark the calls as nobuiltin.
Differential Revision: http://reviews.llvm.org/D19781
llvm-svn: 273083
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index a0dd5d1..4f8935d 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1942,3 +1942,29 @@
InsertedInsts.push_back(CallInst::Create(F, Res->Provider, "rev", I));
return true;
}
+
+// CodeGen has special handling for some string functions that may replace
+// them with target-specific intrinsics. Since that'd skip our interceptors
+// in ASan/MSan/TSan/DFSan, and thus make us miss some memory accesses,
+// we mark affected calls as NoBuiltin, which will disable optimization
+// in CodeGen.
+void llvm::maybeMarkSanitizerLibraryCallNoBuiltin(CallInst *CI,
+ const TargetLibraryInfo *TLI) {
+ Function *F = CI->getCalledFunction();
+ LibFunc::Func Func;
+ if (!F || F->hasLocalLinkage() || !F->hasName() ||
+ !TLI->getLibFunc(F->getName(), Func))
+ return;
+ switch (Func) {
+ default: break;
+ case LibFunc::memcmp:
+ case LibFunc::memchr:
+ case LibFunc::strcpy:
+ case LibFunc::stpcpy:
+ case LibFunc::strcmp:
+ case LibFunc::strlen:
+ case LibFunc::strnlen:
+ CI->addAttribute(AttributeSet::FunctionIndex, Attribute::NoBuiltin);
+ break;
+ }
+}