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))
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
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) {
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
-}
-
-@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
-}
-
-@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
-}