[llvm] r179111 - Revert r176408 and r176407 to address PR15540.
Nadav Rotem
nrotem at apple.com
Tue Apr 9 11:16:05 PDT 2013
Author: nadav
Date: Tue Apr 9 13:16:05 2013
New Revision: 179111
URL: http://llvm.org/viewvc/llvm-project?rev=179111&view=rev
Log:
Revert r176408 and r176407 to address PR15540.
Modified:
llvm/trunk/include/llvm/Analysis/MemoryBuiltins.h
llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
llvm/trunk/lib/Analysis/MemoryBuiltins.cpp
llvm/trunk/test/Transforms/InstCombine/objsize.ll
Modified: llvm/trunk/include/llvm/Analysis/MemoryBuiltins.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/MemoryBuiltins.h?rev=179111&r1=179110&r2=179111&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/MemoryBuiltins.h (original)
+++ llvm/trunk/include/llvm/Analysis/MemoryBuiltins.h Tue Apr 9 13:16:05 2013
@@ -146,14 +146,6 @@ static inline CallInst *isFreeCall(Value
bool getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout *TD,
const TargetLibraryInfo *TLI, bool RoundToAlign = false);
-/// \brief Compute the size of the underlying object pointed by Ptr. Returns
-/// true and the object size in Size if successful, and false otherwise.
-/// If RoundToAlign is true, then Size is rounded up to the aligment of allocas,
-/// byval arguments, and global variables.
-bool getUnderlyingObjectSize(const Value *Ptr, uint64_t &Size,
- const DataLayout *TD, const TargetLibraryInfo *TLI,
- bool RoundToAlign = false);
-
typedef std::pair<APInt, APInt> SizeOffsetType;
@@ -163,14 +155,12 @@ typedef std::pair<APInt, APInt> SizeOffs
class ObjectSizeOffsetVisitor
: public InstVisitor<ObjectSizeOffsetVisitor, SizeOffsetType> {
- typedef DenseMap<const Value*, SizeOffsetType> CacheMapTy;
-
const DataLayout *TD;
const TargetLibraryInfo *TLI;
bool RoundToAlign;
unsigned IntTyBits;
APInt Zero;
- CacheMapTy CacheMap;
+ SmallPtrSet<Instruction *, 8> SeenInsts;
APInt align(APInt Size, uint64_t Align);
Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=179111&r1=179110&r2=179111&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Tue Apr 9 13:16:05 2013
@@ -88,7 +88,7 @@ static uint64_t getObjectSize(const Valu
const TargetLibraryInfo &TLI,
bool RoundToAlign = false) {
uint64_t Size;
- if (getUnderlyingObjectSize(V, Size, &TD, &TLI, RoundToAlign))
+ if (getObjectSize(V, Size, &TD, &TLI, RoundToAlign))
return Size;
return AliasAnalysis::UnknownSize;
}
@@ -98,6 +98,35 @@ static uint64_t getObjectSize(const Valu
static bool isObjectSmallerThan(const Value *V, uint64_t Size,
const DataLayout &TD,
const TargetLibraryInfo &TLI) {
+ // Note that the meanings of the "object" are slightly different in the
+ // following contexts:
+ // c1: llvm::getObjectSize()
+ // c2: llvm.objectsize() intrinsic
+ // c3: isObjectSmallerThan()
+ // c1 and c2 share the same meaning; however, the meaning of "object" in c3
+ // refers to the "entire object".
+ //
+ // Consider this example:
+ // char *p = (char*)malloc(100)
+ // char *q = p+80;
+ //
+ // In the context of c1 and c2, the "object" pointed by q refers to the
+ // stretch of memory of q[0:19]. So, getObjectSize(q) should return 20.
+ //
+ // However, in the context of c3, the "object" refers to the chunk of memory
+ // being allocated. So, the "object" has 100 bytes, and q points to the middle
+ // the "object". In case q is passed to isObjectSmallerThan() as the 1st
+ // parameter, before the llvm::getObjectSize() is called to get the size of
+ // entire object, we should:
+ // - either rewind the pointer q to the base-address of the object in
+ // question (in this case rewind to p), or
+ // - just give up. It is up to caller to make sure the pointer is pointing
+ // to the base address the object.
+ //
+ // We go for 2nd option for simplicity.
+ if (!isIdentifiedObject(V))
+ return false;
+
// This function needs to use the aligned object size because we allow
// reads a bit past the end given sufficient alignment.
uint64_t ObjectSize = getObjectSize(V, TD, TLI, /*RoundToAlign*/true);
Modified: llvm/trunk/lib/Analysis/MemoryBuiltins.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemoryBuiltins.cpp?rev=179111&r1=179110&r2=179111&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/MemoryBuiltins.cpp (original)
+++ llvm/trunk/lib/Analysis/MemoryBuiltins.cpp Tue Apr 9 13:16:05 2013
@@ -364,26 +364,6 @@ bool llvm::getObjectSize(const Value *Pt
return true;
}
-/// \brief Compute the size of the underlying object pointed by Ptr. Returns
-/// true and the object size in Size if successful, and false otherwise.
-/// If RoundToAlign is true, then Size is rounded up to the aligment of allocas,
-/// byval arguments, and global variables.
-bool llvm::getUnderlyingObjectSize(const Value *Ptr, uint64_t &Size,
- const DataLayout *TD,
- const TargetLibraryInfo *TLI,
- bool RoundToAlign) {
- if (!TD)
- return false;
-
- ObjectSizeOffsetVisitor Visitor(TD, TLI, Ptr->getContext(), RoundToAlign);
- SizeOffsetType Data = Visitor.compute(const_cast<Value*>(Ptr));
- if (!Visitor.knownSize(Data))
- return false;
-
- Size = Data.first.getZExtValue();
- return true;
-}
-
STATISTIC(ObjectVisitorArgument,
"Number of arguments with unsolved size and offset");
@@ -409,23 +389,16 @@ ObjectSizeOffsetVisitor::ObjectSizeOffse
SizeOffsetType ObjectSizeOffsetVisitor::compute(Value *V) {
V = V->stripPointerCasts();
+ if (Instruction *I = dyn_cast<Instruction>(V)) {
+ // If we have already seen this instruction, bail out. Cycles can happen in
+ // unreachable code after constant propagation.
+ if (!SeenInsts.insert(I))
+ return unknown();
- if (isa<Instruction>(V) || isa<GEPOperator>(V)) {
- // Return cached value or insert unknown in cache if size of V was not
- // computed yet in order to avoid recursions in PHis.
- std::pair<CacheMapTy::iterator, bool> CacheVal =
- CacheMap.insert(std::make_pair(V, unknown()));
- if (!CacheVal.second)
- return CacheVal.first->second;
-
- SizeOffsetType Result;
if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
- Result = visitGEPOperator(*GEP);
- else
- Result = visit(cast<Instruction>(*V));
- return CacheMap[V] = Result;
+ return visitGEPOperator(*GEP);
+ return visit(*I);
}
-
if (Argument *A = dyn_cast<Argument>(V))
return visitArgument(*A);
if (ConstantPointerNull *P = dyn_cast<ConstantPointerNull>(V))
@@ -439,6 +412,8 @@ SizeOffsetType ObjectSizeOffsetVisitor::
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
if (CE->getOpcode() == Instruction::IntToPtr)
return unknown(); // clueless
+ if (CE->getOpcode() == Instruction::GetElementPtr)
+ return visitGEPOperator(cast<GEPOperator>(*CE));
}
DEBUG(dbgs() << "ObjectSizeOffsetVisitor::compute() unhandled value: " << *V
@@ -572,21 +547,9 @@ SizeOffsetType ObjectSizeOffsetVisitor::
return unknown();
}
-SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode &PHI) {
- if (PHI.getNumIncomingValues() == 0)
- return unknown();
-
- SizeOffsetType Ret = compute(PHI.getIncomingValue(0));
- if (!bothKnown(Ret))
- return unknown();
-
- // Verify that all PHI incoming pointers have the same size and offset.
- for (unsigned i = 1, e = PHI.getNumIncomingValues(); i != e; ++i) {
- SizeOffsetType EdgeData = compute(PHI.getIncomingValue(i));
- if (!bothKnown(EdgeData) || EdgeData != Ret)
- return unknown();
- }
- return Ret;
+SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode&) {
+ // too complex to analyze statically.
+ return unknown();
}
SizeOffsetType ObjectSizeOffsetVisitor::visitSelectInst(SelectInst &I) {
Modified: llvm/trunk/test/Transforms/InstCombine/objsize.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/objsize.ll?rev=179111&r1=179110&r2=179111&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/objsize.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/objsize.ll Tue Apr 9 13:16:05 2013
@@ -256,131 +256,3 @@ xpto:
return:
ret i32 7
}
-
-declare noalias i8* @valloc(i32) nounwind
-
-; CHECK: @test14
-; CHECK: ret i32 6
-define i32 @test14(i32 %a) nounwind {
- switch i32 %a, label %sw.default [
- i32 1, label %sw.bb
- i32 2, label %sw.bb1
- ]
-
-sw.bb:
- %call = tail call noalias i8* @malloc(i32 6) nounwind
- br label %sw.epilog
-
-sw.bb1:
- %call2 = tail call noalias i8* @calloc(i32 3, i32 2) nounwind
- br label %sw.epilog
-
-sw.default:
- %call3 = tail call noalias i8* @valloc(i32 6) nounwind
- br label %sw.epilog
-
-sw.epilog:
- %b.0 = phi i8* [ %call3, %sw.default ], [ %call2, %sw.bb1 ], [ %call, %sw.bb ]
- %1 = tail call i32 @llvm.objectsize.i32(i8* %b.0, i1 false)
- ret i32 %1
-}
-
-; CHECK: @test15
-; CHECK: llvm.objectsize
-define i32 @test15(i32 %a) nounwind {
- switch i32 %a, label %sw.default [
- i32 1, label %sw.bb
- i32 2, label %sw.bb1
- ]
-
-sw.bb:
- %call = tail call noalias i8* @malloc(i32 3) nounwind
- br label %sw.epilog
-
-sw.bb1:
- %call2 = tail call noalias i8* @calloc(i32 2, i32 1) nounwind
- br label %sw.epilog
-
-sw.default:
- %call3 = tail call noalias i8* @valloc(i32 3) nounwind
- br label %sw.epilog
-
-sw.epilog:
- %b.0 = phi i8* [ %call3, %sw.default ], [ %call2, %sw.bb1 ], [ %call, %sw.bb ]
- %1 = tail call i32 @llvm.objectsize.i32(i8* %b.0, i1 false)
- ret i32 %1
-}
-
-; CHECK: @test16
-; CHECK: llvm.objectsize
-define i32 @test16(i8* %a, i32 %n) nounwind {
- %b = alloca [5 x i8], align 1
- %c = alloca [5 x i8], align 1
- switch i32 %n, label %sw.default [
- i32 1, label %sw.bb
- i32 2, label %sw.bb1
- ]
-
-sw.bb:
- %bp = bitcast [5 x i8]* %b to i8*
- br label %sw.epilog
-
-sw.bb1:
- %cp = bitcast [5 x i8]* %c to i8*
- br label %sw.epilog
-
-sw.default:
- br label %sw.epilog
-
-sw.epilog:
- %phi = phi i8* [ %a, %sw.default ], [ %cp, %sw.bb1 ], [ %bp, %sw.bb ]
- %sz = call i32 @llvm.objectsize.i32(i8* %phi, i1 false)
- ret i32 %sz
-}
-
-; CHECK: @test17
-; CHECK: ret i32 5
-define i32 @test17(i32 %n) nounwind {
- %b = alloca [5 x i8], align 1
- %c = alloca [5 x i8], align 1
- %bp = bitcast [5 x i8]* %b to i8*
- switch i32 %n, label %sw.default [
- i32 1, label %sw.bb
- i32 2, label %sw.bb1
- ]
-
-sw.bb:
- br label %sw.epilog
-
-sw.bb1:
- %cp = bitcast [5 x i8]* %c to i8*
- br label %sw.epilog
-
-sw.default:
- br label %sw.epilog
-
-sw.epilog:
- %phi = phi i8* [ %bp, %sw.default ], [ %cp, %sw.bb1 ], [ %bp, %sw.bb ]
- %sz = call i32 @llvm.objectsize.i32(i8* %phi, i1 false)
- ret i32 %sz
-}
-
- at globalalias = alias internal [60 x i8]* @a
-
-; CHECK: @test18
-; CHECK-NEXT: ret i32 60
-define i32 @test18() {
- %bc = bitcast [60 x i8]* @globalalias to i8*
- %1 = call i32 @llvm.objectsize.i32(i8* %bc, i1 false)
- ret i32 %1
-}
-
- at globalalias2 = alias weak [60 x i8]* @a
-
-; CHECK: @test19
-; CHECK: llvm.objectsize
-define i32 @test19() {
- %bc = bitcast [60 x i8]* @globalalias2 to i8*
- %1 = call i32 @llvm.objectsize.i32(i8* %bc, i1 false)
- ret i32 %1
-}
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