[ThinLTO] Record calls to aliases

Summary:
When there is a call to an alias in the same module, we were not
adding a call edge. So we could incorrectly think that the alias
was dead if it was inlined in that function, despite having a
reference imported elsewhere. This resulted in unsats at link time.

Add a call edge when the call is to an alias.

Reviewers: davide, mehdi_amini

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D25384

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283664 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Teresa Johnson
2016-10-08 16:11:42 +00:00
parent a3cf93ab26
commit fd33922422
2 changed files with 40 additions and 1 deletions
+12 -1
View File
@@ -101,15 +101,26 @@ static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
auto CS = ImmutableCallSite(&I);
if (!CS)
continue;
auto *CalledValue = CS.getCalledValue();
auto *CalledFunction = CS.getCalledFunction();
// Check if this is an alias to a function. If so, get the
// called aliasee for the checks below.
if (auto *GA = dyn_cast<GlobalAlias>(CalledValue)) {
assert(!CalledFunction && "Expected null called function in callsite for alias");
CalledFunction = dyn_cast<Function>(GA->getBaseObject());
}
// Check if this is a direct call to a known function.
if (CalledFunction) {
// Skip nameless and intrinsics.
if (!CalledFunction->hasName() || CalledFunction->isIntrinsic())
continue;
auto ScaledCount = BFI ? BFI->getBlockProfileCount(&BB) : None;
// Use the original CalledValue, in case it was an alias. We want
// to record the call edge to the alias in that case. Eventually
// an alias summary will be created to associate the alias and
// aliasee.
auto *CalleeId =
M.getValueSymbolTable().lookup(CalledFunction->getName());
M.getValueSymbolTable().lookup(CalledValue->getName());
auto Hotness = ScaledCount ? getHotness(ScaledCount.getValue(), PSI)
: CalleeInfo::HotnessType::Unknown;