Reverting r171325 & r172363. This was causing a mis-compile on the self-hosted LTO build bots.
Okay, here's how to reproduce the problem:
1) Build a Release (or Release+Asserts) version of clang in the normal way.
2) Using the clang & clang++ binaries from (1), build a Release (or
Release+Asserts) version of the same sources, but this time enable LTO ---
specify the `-flto' flag on the command line.
3) Run the ARC migrator tests:
$ arcmt-test --args -triple x86_64-apple-darwin10 -fsyntax-only -x objective-c++ ./src/tools/clang/test/ARCMT/cxx-rewrite.mm
You'll see that the output isn't correct (the whitespace is off).
The mis-compile is in the function `RewriteBuffer::RemoveText' in the
clang/lib/Rewrite/Core/Rewriter.cpp file. When that function and RewriteRope.cpp
are compiled with LTO and the `arcmt-test' executable is regenerated, you'll see
the error. When those files are not LTO'ed, then the output of the `arcmt-test'
is fine.
It is *really* hard to get a testcase out of this. I'll file a PR with what I
have currently.
--- Reverse-merging r172363 into '.':
U include/llvm/Analysis/MemoryBuiltins.h
U lib/Analysis/MemoryBuiltins.cpp
--- Reverse-merging r171325 into '.':
U test/Transforms/InstCombine/objsize.ll
G include/llvm/Analysis/MemoryBuiltins.h
G lib/Analysis/MemoryBuiltins.cpp
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172756 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
index 1d27a83..0fc0550 100644
--- a/lib/Analysis/MemoryBuiltins.cpp
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -385,23 +385,16 @@
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))
@@ -415,6 +408,8 @@
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
@@ -548,21 +543,9 @@
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) {