[msan] Avoid extra origin address realignment.

Do not realign origin address if the corresponding application
address is at least 4-byte-aligned.

Saves 2.5% code size in track-origins mode.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223464 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evgeniy Stepanov 2014-12-05 14:34:03 +00:00
parent 54529ed1c4
commit c4c08aab64
2 changed files with 97 additions and 21 deletions

View File

@ -522,9 +522,11 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
void storeOrigin(IRBuilder<> &IRB, Value *Addr, Value *Shadow, Value *Origin,
unsigned Alignment, bool AsCall) {
unsigned OriginAlignment = std::max(kMinOriginAlignment, Alignment);
if (isa<StructType>(Shadow->getType())) {
IRB.CreateAlignedStore(updateOrigin(Origin, IRB), getOriginPtr(Addr, IRB),
Alignment);
IRB.CreateAlignedStore(updateOrigin(Origin, IRB),
getOriginPtr(Addr, IRB, Alignment),
OriginAlignment);
} else {
Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
// TODO(eugenis): handle non-zero constant shadow by inserting an
@ -549,7 +551,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Cmp, IRB.GetInsertPoint(), false, MS.OriginStoreWeights);
IRBuilder<> IRBNew(CheckTerm);
IRBNew.CreateAlignedStore(updateOrigin(Origin, IRBNew),
getOriginPtr(Addr, IRBNew), Alignment);
getOriginPtr(Addr, IRBNew, Alignment),
OriginAlignment);
}
}
}
@ -573,11 +576,9 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
if (SI.isAtomic()) SI.setOrdering(addReleaseOrdering(SI.getOrdering()));
if (MS.TrackOrigins) {
unsigned Alignment = std::max(kMinOriginAlignment, SI.getAlignment());
storeOrigin(IRB, Addr, Shadow, getOrigin(Val), Alignment,
if (MS.TrackOrigins)
storeOrigin(IRB, Addr, Shadow, getOrigin(Val), SI.getAlignment(),
InstrumentWithCalls);
}
}
}
@ -739,16 +740,17 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
/// address.
///
/// OriginAddr = (ShadowAddr + OriginOffset) & ~3ULL
Value *getOriginPtr(Value *Addr, IRBuilder<> &IRB) {
Value *getOriginPtr(Value *Addr, IRBuilder<> &IRB, unsigned Alignment) {
Value *ShadowLong =
IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
Value *Add =
IRB.CreateAdd(ShadowLong,
ConstantInt::get(MS.IntptrTy, MS.OriginOffset));
Value *SecondAnd =
IRB.CreateAnd(Add, ConstantInt::get(MS.IntptrTy, ~3ULL));
return IRB.CreateIntToPtr(SecondAnd, PointerType::get(IRB.getInt32Ty(), 0));
IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
Value *Origin = IRB.CreateAdd(
ShadowLong, ConstantInt::get(MS.IntptrTy, MS.OriginOffset));
if (Alignment < kMinOriginAlignment) {
uint64_t Mask = kMinOriginAlignment - 1;
Origin = IRB.CreateAnd(Origin, ConstantInt::get(MS.IntptrTy, ~Mask));
}
return IRB.CreateIntToPtr(Origin, PointerType::get(IRB.getInt32Ty(), 0));
}
/// \brief Compute the shadow address for a given function argument.
@ -1052,9 +1054,10 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
if (MS.TrackOrigins) {
if (PropagateShadow) {
unsigned Alignment = std::max(kMinOriginAlignment, I.getAlignment());
setOrigin(&I,
IRB.CreateAlignedLoad(getOriginPtr(Addr, IRB), Alignment));
unsigned Alignment = I.getAlignment();
unsigned OriginAlignment = std::max(kMinOriginAlignment, Alignment);
setOrigin(&I, IRB.CreateAlignedLoad(getOriginPtr(Addr, IRB, Alignment),
OriginAlignment));
} else {
setOrigin(&I, getCleanOrigin());
}
@ -1706,7 +1709,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
// FIXME: use ClStoreCleanOrigin
// FIXME: factor out common code from materializeStores
if (MS.TrackOrigins)
IRB.CreateStore(getOrigin(&I, 1), getOriginPtr(Addr, IRB));
IRB.CreateStore(getOrigin(&I, 1), getOriginPtr(Addr, IRB, 1));
return true;
}
@ -1733,7 +1736,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
if (MS.TrackOrigins) {
if (PropagateShadow)
setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB)));
setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB, 1)));
else
setOrigin(&I, getCleanOrigin());
}

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@ -0,0 +1,73 @@
; RUN: opt < %s -msan -msan-check-access-address=0 -msan-track-origins=1 -S | FileCheck -check-prefix=CHECK -check-prefix=CHECK-ORIGINS1 %s
; RUN: opt < %s -msan -msan-check-access-address=0 -msan-track-origins=2 -S | FileCheck -check-prefix=CHECK -check-prefix=CHECK-ORIGINS2 %s
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"
; Check origin instrumentation of stores.
; Check that debug info for origin propagation code is set correctly.
@a8 = global i8 0, align 8
@a4 = global i8 0, align 4
@a2 = global i8 0, align 2
@a1 = global i8 0, align 1
; 8-aligned store => 8-aligned origin store, origin address is not realigned
define void @Store8(i8 %x) sanitize_memory {
entry:
store i8 %x, i8* @a8, align 8
ret void
}
; CHECK-LABEL: @Store8
; CHECK-ORIGINS1: [[ORIGIN:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls
; CHECK-ORIGINS2: [[ORIGIN0:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls
; CHECK-ORIGINS2: [[ORIGIN:%[01-9a-z]+]] = call i32 @__msan_chain_origin(i32 [[ORIGIN0]])
; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 add (i64 and (i64 ptrtoint {{.*}} to i32*), align 8
; CHECK: ret void
; 4-aligned store => 4-aligned origin store, origin address is not realigned
define void @Store4(i8 %x) sanitize_memory {
entry:
store i8 %x, i8* @a4, align 4
ret void
}
; CHECK-LABEL: @Store4
; CHECK-ORIGINS1: [[ORIGIN:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls
; CHECK-ORIGINS2: [[ORIGIN0:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls
; CHECK-ORIGINS2: [[ORIGIN:%[01-9a-z]+]] = call i32 @__msan_chain_origin(i32 [[ORIGIN0]])
; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 add (i64 and (i64 ptrtoint {{.*}} to i32*), align 4
; CHECK: ret void
; 2-aligned store => 4-aligned origin store, origin address is realigned
define void @Store2(i8 %x) sanitize_memory {
entry:
store i8 %x, i8* @a2, align 2
ret void
}
; CHECK-LABEL: @Store2
; CHECK-ORIGINS1: [[ORIGIN:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls
; CHECK-ORIGINS2: [[ORIGIN0:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls
; CHECK-ORIGINS2: [[ORIGIN:%[01-9a-z]+]] = call i32 @__msan_chain_origin(i32 [[ORIGIN0]])
; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 and (i64 add (i64 and (i64 ptrtoint {{.*}} i64 -4) to i32*), align 4
; CHECK: ret void
; 1-aligned store => 4-aligned origin store, origin address is realigned
define void @Store1(i8 %x) sanitize_memory {
entry:
store i8 %x, i8* @a1, align 1
ret void
}
; CHECK-LABEL: @Store1
; CHECK-ORIGINS1: [[ORIGIN:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls
; CHECK-ORIGINS2: [[ORIGIN0:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls
; CHECK-ORIGINS2: [[ORIGIN:%[01-9a-z]+]] = call i32 @__msan_chain_origin(i32 [[ORIGIN0]])
; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 and (i64 add (i64 and (i64 ptrtoint {{.*}} i64 -4) to i32*), align 4
; CHECK: ret void