[msan] Instrument x86 BMI intrinsics.
Summary:
They simply shuffle bits. MSan needs to do the same with shadow bits,
after making sure that the shuffle mask is fully initialized.
Reviewers: pcc, vitalybuka
Subscribers: hiraditya, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D58858
llvm-svn: 355348
diff --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index 4b217e9..bfa1d0f 100644
--- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -2928,6 +2928,26 @@
return true;
}
+ // Instrument BMI / BMI2 intrinsics.
+ // All of these intrinsics are Z = I(X, Y)
+ // where the types of all operands and the result match, and are either i32 or i64.
+ // The following instrumentation happens to work for all of them:
+ // Sz = I(Sx, Y) | (sext (Sy != 0))
+ void handleBmiIntrinsic(IntrinsicInst &I) {
+ IRBuilder<> IRB(&I);
+ Type *ShadowTy = getShadowTy(&I);
+
+ // If any bit of the mask operand is poisoned, then the whole thing is.
+ Value *SMask = getShadow(&I, 1);
+ SMask = IRB.CreateSExt(IRB.CreateICmpNE(SMask, getCleanShadow(ShadowTy)),
+ ShadowTy);
+ // Apply the same intrinsic to the shadow of the first operand.
+ Value *S = IRB.CreateCall(I.getCalledFunction(),
+ {getShadow(&I, 0), I.getOperand(1)});
+ S = IRB.CreateOr(SMask, S);
+ setShadow(&I, S);
+ setOriginForNaryOp(I);
+ }
void visitIntrinsicInst(IntrinsicInst &I) {
switch (I.getIntrinsicID()) {
@@ -3144,6 +3164,17 @@
handleVectorComparePackedIntrinsic(I);
break;
+ case Intrinsic::x86_bmi_bextr_32:
+ case Intrinsic::x86_bmi_bextr_64:
+ case Intrinsic::x86_bmi_bzhi_32:
+ case Intrinsic::x86_bmi_bzhi_64:
+ case Intrinsic::x86_bmi_pdep_32:
+ case Intrinsic::x86_bmi_pdep_64:
+ case Intrinsic::x86_bmi_pext_32:
+ case Intrinsic::x86_bmi_pext_64:
+ handleBmiIntrinsic(I);
+ break;
+
case Intrinsic::is_constant:
// The result of llvm.is.constant() is always defined.
setShadow(&I, getCleanShadow(&I));