From 203f7cb68b6c509b388d1662d8439693f75bb964 Mon Sep 17 00:00:00 2001 From: Duncan Sands Date: Tue, 4 May 2010 12:43:36 +0000 Subject: Fix a variant of PR6112 found by thinking about it: when doing RAUW of a global variable with a local variable in function F, if function local metadata M in function G was using the global then M would become function-local to both F and G, which is not allowed. See the testcase for an example. Fixed by detecting this situation and zapping the metadata operand when it occurs. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103007 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/VMCore/Metadata.cpp | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) (limited to 'lib/VMCore/Metadata.cpp') diff --git a/lib/VMCore/Metadata.cpp b/lib/VMCore/Metadata.cpp index 092fe00a53..73376f5a6b 100644 --- a/lib/VMCore/Metadata.cpp +++ b/lib/VMCore/Metadata.cpp @@ -115,14 +115,17 @@ MDNode::~MDNode() { } static const Function *getFunctionForValue(Value *V) { - assert(!isa(V) && "does not iterate over metadata operands"); if (!V) return NULL; - if (Instruction *I = dyn_cast(V)) - return I->getParent()->getParent(); - if (BasicBlock *BB = dyn_cast(V)) - return BB->getParent(); + if (Instruction *I = dyn_cast(V)) { + BasicBlock *BB = I->getParent(); + return BB ? BB->getParent() : 0; + } if (Argument *A = dyn_cast(V)) return A->getParent(); + if (BasicBlock *BB = dyn_cast(V)) + return BB->getParent(); + if (MDNode *MD = dyn_cast(V)) + return MD->getFunction(); return NULL; } @@ -272,8 +275,19 @@ void MDNode::replaceOperand(MDNodeOperand *Op, Value *To) { // with an instruction or some other function-local object. If this is a // non-function-local MDNode, it can't point to a function-local object. // Handle this case by implicitly dropping the MDNode reference to null. - if (!isFunctionLocal() && To && isFunctionLocalValue(To)) - To = 0; + // Likewise if the MDNode is function-local but for a different function. + if (To && isFunctionLocalValue(To)) { + if (!isFunctionLocal()) + To = 0; + else { + const Function *F = getFunction(); + const Function *FV = getFunctionForValue(To); + // Metadata can be function-local without having an associated function. + // So only consider functions to have changed if non-null. + if (F && FV && F != FV) + To = 0; + } + } if (From == To) return; -- cgit v1.2.3