[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

1 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 16a55527c20..599b2cc5b36 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -1765,6 +1765,8 @@ bool AddressSanitizer::runOnFunction(Function &F) {
   bool IsWrite;
   unsigned Alignment;
   uint64_t TypeSize;
+  const TargetLibraryInfo *TLI =
+      &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
 
   // Fill the set of memory operations to instrument.
   for (auto &BB : F) {
@@ -1793,6 +1795,8 @@ bool AddressSanitizer::runOnFunction(Function &F) {
           TempsToInstrument.clear();
           if (CS.doesNotReturn()) NoReturnCalls.push_back(CS.getInstruction());
         }
+        if (CallInst *CI = dyn_cast<CallInst>(&Inst))
+          maybeMarkSanitizerLibraryCallNoBuiltin(CI, TLI);
         continue;
       }
       ToInstrument.push_back(&Inst);
@@ -1805,8 +1809,6 @@ bool AddressSanitizer::runOnFunction(Function &F) {
       CompileKernel ||
       (ClInstrumentationWithCallsThreshold >= 0 &&
        ToInstrument.size() > (unsigned)ClInstrumentationWithCallsThreshold);
-  const TargetLibraryInfo *TLI =
-      &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
   const DataLayout &DL = F.getParent()->getDataLayout();
   ObjectSizeOffsetVisitor ObjSizeVis(DL, TLI, F.getContext(),
                                      /*RoundToAlign=*/true);