aboutsummaryrefslogtreecommitdiffstats
path: root/lib/Analysis/BasicAliasAnalysis.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/Analysis/BasicAliasAnalysis.cpp')
-rw-r--r--lib/Analysis/BasicAliasAnalysis.cpp116
1 files changed, 50 insertions, 66 deletions
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index a3bc06a..ca668b2 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -13,28 +13,28 @@
//
//===----------------------------------------------------------------------===//
-#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/Passes.h"
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Function.h"
-#include "llvm/GlobalAlias.h"
-#include "llvm/GlobalVariable.h"
-#include "llvm/Instructions.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/Operator.h"
-#include "llvm/Pass.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/CaptureTracking.h"
-#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Target/TargetLibraryInfo.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallVector.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalAlias.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Operator.h"
+#include "llvm/Pass.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
+#include "llvm/Target/TargetLibraryInfo.h"
#include <algorithm>
using namespace llvm;
@@ -58,12 +58,12 @@ static bool isNonEscapingLocalObject(const Value *V) {
// then it has not escaped before entering the function. Check if it escapes
// inside the function.
if (const Argument *A = dyn_cast<Argument>(V))
- if (A->hasByValAttr() || A->hasNoAliasAttr()) {
- // Don't bother analyzing arguments already known not to escape.
- if (A->hasNoCaptureAttr())
- return true;
+ if (A->hasByValAttr() || A->hasNoAliasAttr())
+ // Note even if the argument is marked nocapture we still need to check
+ // for copies made inside the function. The nocapture attribute only
+ // specifies that there are no copies made that outlive the function.
return !PointerMayBeCaptured(V, false, /*StoreCaptures=*/true);
- }
+
return false;
}
@@ -84,7 +84,7 @@ static bool isEscapeSource(const Value *V) {
/// getObjectSize - Return the size of the object specified by V, or
/// UnknownSize if unknown.
-static uint64_t getObjectSize(const Value *V, const TargetData &TD,
+static uint64_t getObjectSize(const Value *V, const DataLayout &TD,
const TargetLibraryInfo &TLI,
bool RoundToAlign = false) {
uint64_t Size;
@@ -96,7 +96,7 @@ static uint64_t getObjectSize(const Value *V, const TargetData &TD,
/// isObjectSmallerThan - Return true if we can prove that the object specified
/// by V is smaller than Size.
static bool isObjectSmallerThan(const Value *V, uint64_t Size,
- const TargetData &TD,
+ const DataLayout &TD,
const TargetLibraryInfo &TLI) {
// This function needs to use the aligned object size because we allow
// reads a bit past the end given sufficient alignment.
@@ -108,7 +108,7 @@ static bool isObjectSmallerThan(const Value *V, uint64_t Size,
/// isObjectSize - Return true if we can prove that the object specified
/// by V has size Size.
static bool isObjectSize(const Value *V, uint64_t Size,
- const TargetData &TD, const TargetLibraryInfo &TLI) {
+ const DataLayout &TD, const TargetLibraryInfo &TLI) {
uint64_t ObjectSize = getObjectSize(V, TD, TLI);
return ObjectSize != AliasAnalysis::UnknownSize && ObjectSize == Size;
}
@@ -151,7 +151,7 @@ namespace {
/// represented in the result.
static Value *GetLinearExpression(Value *V, APInt &Scale, APInt &Offset,
ExtensionKind &Extension,
- const TargetData &TD, unsigned Depth) {
+ const DataLayout &TD, unsigned Depth) {
assert(V->getType()->isIntegerTy() && "Not an integer value");
// Limit our recursion depth.
@@ -226,14 +226,14 @@ static Value *GetLinearExpression(Value *V, APInt &Scale, APInt &Offset,
/// specified amount, but which may have other unrepresented high bits. As such,
/// the gep cannot necessarily be reconstructed from its decomposed form.
///
-/// When TargetData is around, this function is capable of analyzing everything
+/// When DataLayout is around, this function is capable of analyzing everything
/// that GetUnderlyingObject can look through. When not, it just looks
/// through pointer casts.
///
static const Value *
DecomposeGEPExpression(const Value *V, int64_t &BaseOffs,
SmallVectorImpl<VariableGEPIndex> &VarIndices,
- const TargetData *TD) {
+ const DataLayout *TD) {
// Limit recursion depth to limit compile time in crazy cases.
unsigned MaxLookup = 6;
@@ -277,7 +277,7 @@ DecomposeGEPExpression(const Value *V, int64_t &BaseOffs,
->getElementType()->isSized())
return V;
- // If we are lacking TargetData information, we can't compute the offets of
+ // If we are lacking DataLayout information, we can't compute the offets of
// elements computed by GEPs. However, we can handle bitcast equivalent
// GEPs.
if (TD == 0) {
@@ -631,7 +631,7 @@ BasicAliasAnalysis::getModRefBehavior(const Function *F) {
// For intrinsics, we can check the table.
if (unsigned iid = F->getIntrinsicID()) {
#define GET_INTRINSIC_MODREF_BEHAVIOR
-#include "llvm/Intrinsics.gen"
+#include "llvm/IR/Intrinsics.gen"
#undef GET_INTRINSIC_MODREF_BEHAVIOR
}
@@ -868,7 +868,7 @@ BasicAliasAnalysis::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
const Value *GEP1BasePtr =
DecomposeGEPExpression(GEP1, GEP1BaseOffset, GEP1VariableIndices, TD);
// DecomposeGEPExpression and GetUnderlyingObject should return the
- // same result except when DecomposeGEPExpression has no TargetData.
+ // same result except when DecomposeGEPExpression has no DataLayout.
if (GEP1BasePtr != UnderlyingV1 || GEP2BasePtr != UnderlyingV2) {
assert(TD == 0 &&
"DecomposeGEPExpression and GetUnderlyingObject disagree!");
@@ -902,7 +902,7 @@ BasicAliasAnalysis::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
DecomposeGEPExpression(GEP2, GEP2BaseOffset, GEP2VariableIndices, TD);
// DecomposeGEPExpression and GetUnderlyingObject should return the
- // same result except when DecomposeGEPExpression has no TargetData.
+ // same result except when DecomposeGEPExpression has no DataLayout.
if (GEP1BasePtr != UnderlyingV1 || GEP2BasePtr != UnderlyingV2) {
assert(TD == 0 &&
"DecomposeGEPExpression and GetUnderlyingObject disagree!");
@@ -937,7 +937,7 @@ BasicAliasAnalysis::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
DecomposeGEPExpression(GEP1, GEP1BaseOffset, GEP1VariableIndices, TD);
// DecomposeGEPExpression and GetUnderlyingObject should return the
- // same result except when DecomposeGEPExpression has no TargetData.
+ // same result except when DecomposeGEPExpression has no DataLayout.
if (GEP1BasePtr != UnderlyingV1) {
assert(TD == 0 &&
"DecomposeGEPExpression and GetUnderlyingObject disagree!");
@@ -1064,39 +1064,20 @@ BasicAliasAnalysis::aliasPHI(const PHINode *PN, uint64_t PNSize,
Location(V2, V2Size, V2TBAAInfo));
if (PN > V2)
std::swap(Locs.first, Locs.second);
-
- AliasResult Alias =
- aliasCheck(PN->getIncomingValue(0), PNSize, PNTBAAInfo,
- PN2->getIncomingValueForBlock(PN->getIncomingBlock(0)),
- V2Size, V2TBAAInfo);
- if (Alias == MayAlias)
- return MayAlias;
-
- // If the first source of the PHI nodes NoAlias and the other inputs are
- // the PHI node itself through some amount of recursion this does not add
- // any new information so just return NoAlias.
- // bb:
- // ptr = ptr2 + 1
- // loop:
- // ptr_phi = phi [bb, ptr], [loop, ptr_plus_one]
- // ptr2_phi = phi [bb, ptr2], [loop, ptr2_plus_one]
- // ...
- // ptr_plus_one = gep ptr_phi, 1
- // ptr2_plus_one = gep ptr2_phi, 1
- // We assume for the recursion that the the phis (ptr_phi, ptr2_phi) do
- // not alias each other.
- bool ArePhisAssumedNoAlias = false;
- AliasResult OrigAliasResult;
- if (Alias == NoAlias) {
- // Pretend the phis do not alias.
- assert(AliasCache.count(Locs) &&
- "There must exist an entry for the phi node");
- OrigAliasResult = AliasCache[Locs];
- AliasCache[Locs] = NoAlias;
- ArePhisAssumedNoAlias = true;
- }
-
- for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) {
+ // Analyse the PHIs' inputs under the assumption that the PHIs are
+ // NoAlias.
+ // If the PHIs are May/MustAlias there must be (recursively) an input
+ // operand from outside the PHIs' cycle that is MayAlias/MustAlias or
+ // there must be an operation on the PHIs within the PHIs' value cycle
+ // that causes a MayAlias.
+ // Pretend the phis do not alias.
+ AliasResult Alias = NoAlias;
+ assert(AliasCache.count(Locs) &&
+ "There must exist an entry for the phi node");
+ AliasResult OrigAliasResult = AliasCache[Locs];
+ AliasCache[Locs] = NoAlias;
+
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
AliasResult ThisAlias =
aliasCheck(PN->getIncomingValue(i), PNSize, PNTBAAInfo,
PN2->getIncomingValueForBlock(PN->getIncomingBlock(i)),
@@ -1107,7 +1088,7 @@ BasicAliasAnalysis::aliasPHI(const PHINode *PN, uint64_t PNSize,
}
// Reset if speculation failed.
- if (ArePhisAssumedNoAlias && Alias != NoAlias)
+ if (Alias != NoAlias)
AliasCache[Locs] = OrigAliasResult;
return Alias;
@@ -1245,6 +1226,7 @@ BasicAliasAnalysis::aliasCheck(const Value *V1, uint64_t V1Size,
std::swap(V1, V2);
std::swap(V1Size, V2Size);
std::swap(O1, O2);
+ std::swap(V1TBAAInfo, V2TBAAInfo);
}
if (const GEPOperator *GV1 = dyn_cast<GEPOperator>(V1)) {
AliasResult Result = aliasGEP(GV1, V1Size, V1TBAAInfo, V2, V2Size, V2TBAAInfo, O1, O2);
@@ -1254,6 +1236,7 @@ BasicAliasAnalysis::aliasCheck(const Value *V1, uint64_t V1Size,
if (isa<PHINode>(V2) && !isa<PHINode>(V1)) {
std::swap(V1, V2);
std::swap(V1Size, V2Size);
+ std::swap(V1TBAAInfo, V2TBAAInfo);
}
if (const PHINode *PN = dyn_cast<PHINode>(V1)) {
AliasResult Result = aliasPHI(PN, V1Size, V1TBAAInfo,
@@ -1264,6 +1247,7 @@ BasicAliasAnalysis::aliasCheck(const Value *V1, uint64_t V1Size,
if (isa<SelectInst>(V2) && !isa<SelectInst>(V1)) {
std::swap(V1, V2);
std::swap(V1Size, V2Size);
+ std::swap(V1TBAAInfo, V2TBAAInfo);
}
if (const SelectInst *S1 = dyn_cast<SelectInst>(V1)) {
AliasResult Result = aliasSelect(S1, V1Size, V1TBAAInfo,
generated by cgit v1.1 at 2025-11-11 07:16:41 +0000