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[msan] Instrument x86.pclmulqdq* intrinsics.

Summary:
These instructions ignore parts of the input vectors which makes the
default MSan handling too strict and causes false positive reports.

Reviewers: vitalybuka, RKSimon, thakis

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73374
This commit is contained in:
Evgenii Stepanov 2020-01-24 11:08:49 -08:00
parent 3ef629d443
commit 67d6f58389
2 changed files with 115 additions and 0 deletions

View File

@ -3000,6 +3000,43 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
setOriginForNaryOp(I);
}
Constant *getPclmulMask(IRBuilder<> &IRB, unsigned Width, bool OddElements) {
SmallVector<Constant *, 8> Mask;
for (unsigned X = OddElements ? 1 : 0; X < Width; X += 2) {
Constant *C = ConstantInt::get(IRB.getInt32Ty(), X);
Mask.push_back(C);
Mask.push_back(C);
}
return ConstantVector::get(Mask);
}
// Instrument pclmul intrinsics.
// These intrinsics operate either on odd or on even elements of the input
// vectors, depending on the constant in the 3rd argument, ignoring the rest.
// Replace the unused elements with copies of the used ones, ex:
// (0, 1, 2, 3) -> (0, 0, 2, 2) (even case)
// or
// (0, 1, 2, 3) -> (1, 1, 3, 3) (odd case)
// and then apply the usual shadow combining logic.
void handlePclmulIntrinsic(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Type *ShadowTy = getShadowTy(&I);
unsigned Width = I.getArgOperand(0)->getType()->getVectorNumElements();
assert(isa<ConstantInt>(I.getArgOperand(2)) &&
"pclmul 3rd operand must be a constant");
unsigned Imm = cast<ConstantInt>(I.getArgOperand(2))->getZExtValue();
Value *Shuf0 =
IRB.CreateShuffleVector(getShadow(&I, 0), UndefValue::get(ShadowTy),
getPclmulMask(IRB, Width, Imm & 0x01));
Value *Shuf1 =
IRB.CreateShuffleVector(getShadow(&I, 1), UndefValue::get(ShadowTy),
getPclmulMask(IRB, Width, Imm & 0x10));
ShadowAndOriginCombiner SOC(this, IRB);
SOC.Add(Shuf0, getOrigin(&I, 0));
SOC.Add(Shuf1, getOrigin(&I, 1));
SOC.Done(&I);
}
void visitIntrinsicInst(IntrinsicInst &I) {
switch (I.getIntrinsicID()) {
case Intrinsic::lifetime_start:
@ -3233,6 +3270,12 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
handleBmiIntrinsic(I);
break;
case Intrinsic::x86_pclmulqdq:
case Intrinsic::x86_pclmulqdq_256:
case Intrinsic::x86_pclmulqdq_512:
handlePclmulIntrinsic(I);
break;
case Intrinsic::is_constant:
// The result of llvm.is.constant() is always defined.
setShadow(&I, getCleanShadow(&I));

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@ -0,0 +1,72 @@
; RUN: opt < %s -msan-check-access-address=0 -S -passes=msan 2>&1 | FileCheck \
; RUN: %s
; RUN: opt < %s -msan -msan-check-access-address=0 -S | FileCheck %s
; RUN: opt < %s -msan -msan-check-access-address=0 -msan-track-origins=1 -S | FileCheck %s --check-prefixes=CHECK,ORIGIN
; REQUIRES: x86-registered-target
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
declare <2 x i64> @llvm.x86.pclmulqdq(<2 x i64>, <2 x i64>, i8 immarg) nounwind readnone
declare <4 x i64> @llvm.x86.pclmulqdq.256(<4 x i64>, <4 x i64>, i8 immarg) nounwind readnone
declare <8 x i64> @llvm.x86.pclmulqdq.512(<8 x i64>, <8 x i64>, i8 immarg) nounwind readnone
define <2 x i64> @clmul00(<2 x i64> %a, <2 x i64> %b) sanitize_memory {
entry:
%0 = tail call <2 x i64> @llvm.x86.pclmulqdq(<2 x i64> %a, <2 x i64> %b, i8 0)
ret <2 x i64> %0
}
; CHECK-LABEL: @clmul00
; CHECK: %[[S0:.*]] = load <2 x i64>, <2 x i64>* {{.*}}@__msan_param_tls
; CHECK: %[[S1:.*]] = load <2 x i64>, <2 x i64>* {{.*}}@__msan_param_tls
; CHECK: %[[SHUF1:.*]] = shufflevector <2 x i64> %[[S1]], <2 x i64> undef, <2 x i32> zeroinitializer
; CHECK: %[[SHUF0:.*]] = shufflevector <2 x i64> %[[S0]], <2 x i64> undef, <2 x i32> zeroinitializer
; CHECK: %[[SRET:.*]] = or <2 x i64> %[[SHUF1]], %[[SHUF0]]
; CHECK: store <2 x i64> %[[SRET]], <2 x i64>* {{.*}}@__msan_retval_tls
define <2 x i64> @clmul10(<2 x i64> %a, <2 x i64> %b) sanitize_memory {
entry:
%0 = tail call <2 x i64> @llvm.x86.pclmulqdq(<2 x i64> %a, <2 x i64> %b, i8 16)
ret <2 x i64> %0
}
; CHECK-LABEL: @clmul10
; CHECK: %[[S0:.*]] = load <2 x i64>, <2 x i64>* {{.*}}@__msan_param_tls
; CHECK: %[[S1:.*]] = load <2 x i64>, <2 x i64>* {{.*}}@__msan_param_tls
; CHECK: %[[SHUF1:.*]] = shufflevector <2 x i64> %[[S1]], <2 x i64> undef, <2 x i32> zeroinitializer
; CHECK: %[[SHUF0:.*]] = shufflevector <2 x i64> %[[S0]], <2 x i64> undef, <2 x i32> <i32 1, i32 1>
; CHECK: %[[SRET:.*]] = or <2 x i64> %[[SHUF1]], %[[SHUF0]]
; CHECK: store <2 x i64> %[[SRET]], <2 x i64>* {{.*}}@__msan_retval_tls
define <4 x i64> @clmul11_256(<4 x i64> %a, <4 x i64> %b) sanitize_memory {
entry:
%0 = tail call <4 x i64> @llvm.x86.pclmulqdq.256(<4 x i64> %a, <4 x i64> %b, i8 17)
ret <4 x i64> %0
}
; CHECK-LABEL: @clmul11_256
; CHECK: %[[S0:.*]] = load <4 x i64>, <4 x i64>* {{.*}}@__msan_param_tls
; CHECK: %[[S1:.*]] = load <4 x i64>, <4 x i64>* {{.*}}@__msan_param_tls
; CHECK: %[[SHUF1:.*]] = shufflevector <4 x i64> %[[S1]], <4 x i64> undef, <4 x i32> <i32 1, i32 1, i32 3, i32 3>
; CHECK: %[[SHUF0:.*]] = shufflevector <4 x i64> %[[S0]], <4 x i64> undef, <4 x i32> <i32 1, i32 1, i32 3, i32 3>
; CHECK: %[[SRET:.*]] = or <4 x i64> %[[SHUF1]], %[[SHUF0]]
; CHECK: store <4 x i64> %[[SRET]], <4 x i64>* {{.*}}@__msan_retval_tls
define <8 x i64> @clmul01_512(<8 x i64> %a, <8 x i64> %b) sanitize_memory {
entry:
%0 = tail call <8 x i64> @llvm.x86.pclmulqdq.512(<8 x i64> %a, <8 x i64> %b, i8 16)
ret <8 x i64> %0
}
; CHECK-LABEL: @clmul01_512
; CHECK: %[[S0:.*]] = load <8 x i64>, <8 x i64>* {{.*}}@__msan_param_tls
; CHECK: %[[S1:.*]] = load <8 x i64>, <8 x i64>* {{.*}}@__msan_param_tls
; CHECK: %[[SHUF1:.*]] = shufflevector <8 x i64> %[[S1]], <8 x i64> undef, <8 x i32> <i32 0, i32 0, i32 2, i32 2, i32 4, i32 4, i32 6, i32 6>
; CHECK: %[[SHUF0:.*]] = shufflevector <8 x i64> %[[S0]], <8 x i64> undef, <8 x i32> <i32 1, i32 1, i32 3, i32 3, i32 5, i32 5, i32 7, i32 7>
; CHECK: %[[SRET:.*]] = or <8 x i64> %[[SHUF1]], %[[SHUF0]]
; ORIGIN: %[[FLAT:.*]] = bitcast <8 x i64> %[[SHUF0]] to i512
; ORIGIN: %[[I:.*]] = icmp ne i512 %[[FLAT]], 0
; ORIGIN: %[[O:.*]] = select i1 %[[I]],
; CHECK: store <8 x i64> %[[SRET]], <8 x i64>* {{.*}}@__msan_retval_tls
; ORIGIN: store i32 %[[O]], i32* @__msan_retval_origin_tls