[ThinLTO] Internalize readonly globals
An attempt to recommit r346584 after failure on OSX build bot.
Fixed cache key computation in ThinLTOCodeGenerator and added
test case
llvm-svn: 347033
diff --git a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
index f042178..237faed 100644
--- a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -220,10 +220,19 @@
}
}
-static void computeFunctionSummary(
- ModuleSummaryIndex &Index, const Module &M, const Function &F,
- BlockFrequencyInfo *BFI, ProfileSummaryInfo *PSI, DominatorTree &DT,
- bool HasLocalsInUsedOrAsm, DenseSet<GlobalValue::GUID> &CantBePromoted) {
+static bool isNonVolatileLoad(const Instruction *I) {
+ if (const auto *LI = dyn_cast<LoadInst>(I))
+ return !LI->isVolatile();
+
+ return false;
+}
+
+static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
+ const Function &F, BlockFrequencyInfo *BFI,
+ ProfileSummaryInfo *PSI, DominatorTree &DT,
+ bool HasLocalsInUsedOrAsm,
+ DenseSet<GlobalValue::GUID> &CantBePromoted,
+ bool IsThinLTO) {
// Summary not currently supported for anonymous functions, they should
// have been named.
assert(F.hasName());
@@ -244,6 +253,7 @@
// Add personality function, prefix data and prologue data to function's ref
// list.
findRefEdges(Index, &F, RefEdges, Visited);
+ std::vector<const Instruction *> NonVolatileLoads;
bool HasInlineAsmMaybeReferencingInternal = false;
bool InitsVarArgs = false;
@@ -256,6 +266,13 @@
InitsVarArgs = true;
}
++NumInsts;
+ if (isNonVolatileLoad(&I)) {
+ // Postpone processing of non-volatile load instructions
+ // See comments below
+ Visited.insert(&I);
+ NonVolatileLoads.push_back(&I);
+ continue;
+ }
findRefEdges(Index, &I, RefEdges, Visited);
auto CS = ImmutableCallSite(&I);
if (!CS)
@@ -345,6 +362,24 @@
}
}
+ // By now we processed all instructions in a function, except
+ // non-volatile loads. All new refs we add in a loop below
+ // are obviously constant. All constant refs are grouped in the
+ // end of RefEdges vector, so we can use a single integer value
+ // to identify them.
+ unsigned RefCnt = RefEdges.size();
+ for (const Instruction *I : NonVolatileLoads) {
+ Visited.erase(I);
+ findRefEdges(Index, I, RefEdges, Visited);
+ }
+ std::vector<ValueInfo> Refs = RefEdges.takeVector();
+ // Regular LTO module doesn't participate in ThinLTO import,
+ // so no reference from it can be readonly, since this would
+ // require importing variable as local copy
+ if (IsThinLTO)
+ for (; RefCnt < Refs.size(); ++RefCnt)
+ Refs[RefCnt].setReadOnly();
+
// Explicit add hot edges to enforce importing for designated GUIDs for
// sample PGO, to enable the same inlines as the profiled optimized binary.
for (auto &I : F.getImportGUIDs())
@@ -368,9 +403,9 @@
// Don't try to import functions with noinline attribute.
F.getAttributes().hasFnAttribute(Attribute::NoInline)};
auto FuncSummary = llvm::make_unique<FunctionSummary>(
- Flags, NumInsts, FunFlags, RefEdges.takeVector(),
- CallGraphEdges.takeVector(), TypeTests.takeVector(),
- TypeTestAssumeVCalls.takeVector(), TypeCheckedLoadVCalls.takeVector(),
+ Flags, NumInsts, FunFlags, std::move(Refs), CallGraphEdges.takeVector(),
+ TypeTests.takeVector(), TypeTestAssumeVCalls.takeVector(),
+ TypeCheckedLoadVCalls.takeVector(),
TypeTestAssumeConstVCalls.takeVector(),
TypeCheckedLoadConstVCalls.takeVector());
if (NonRenamableLocal)
@@ -387,8 +422,13 @@
bool NonRenamableLocal = isNonRenamableLocal(V);
GlobalValueSummary::GVFlags Flags(V.getLinkage(), NonRenamableLocal,
/* Live = */ false, V.isDSOLocal());
- auto GVarSummary =
- llvm::make_unique<GlobalVarSummary>(Flags, RefEdges.takeVector());
+
+ // Don't mark variables we won't be able to internalize as read-only.
+ GlobalVarSummary::GVarFlags VarFlags(
+ !V.hasComdat() && !V.hasAppendingLinkage() && !V.isInterposable() &&
+ !V.hasAvailableExternallyLinkage() && !V.hasDLLExportStorageClass());
+ auto GVarSummary = llvm::make_unique<GlobalVarSummary>(Flags, VarFlags,
+ RefEdges.takeVector());
if (NonRenamableLocal)
CantBePromoted.insert(V.getGUID());
if (HasBlockAddress)
@@ -492,13 +532,19 @@
Index.addGlobalValueSummary(*GV, std::move(Summary));
} else {
std::unique_ptr<GlobalVarSummary> Summary =
- llvm::make_unique<GlobalVarSummary>(GVFlags,
- ArrayRef<ValueInfo>{});
+ llvm::make_unique<GlobalVarSummary>(
+ GVFlags, GlobalVarSummary::GVarFlags(),
+ ArrayRef<ValueInfo>{});
Index.addGlobalValueSummary(*GV, std::move(Summary));
}
});
}
+ bool IsThinLTO = true;
+ if (auto *MD =
+ mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
+ IsThinLTO = MD->getZExtValue();
+
// Compute summaries for all functions defined in module, and save in the
// index.
for (auto &F : M) {
@@ -519,7 +565,7 @@
computeFunctionSummary(Index, M, F, BFI, PSI, DT,
!LocalsUsed.empty() || HasLocalInlineAsmSymbol,
- CantBePromoted);
+ CantBePromoted, IsThinLTO);
}
// Compute summaries for all variables defined in module, and save in the
@@ -550,11 +596,6 @@
setLiveRoot(Index, "llvm.global_dtors");
setLiveRoot(Index, "llvm.global.annotations");
- bool IsThinLTO = true;
- if (auto *MD =
- mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
- IsThinLTO = MD->getZExtValue();
-
for (auto &GlobalList : Index) {
// Ignore entries for references that are undefined in the current module.
if (GlobalList.second.SummaryList.empty())