[llvm-branch-commits] [llvm] [Coro] Prebuild a module-level debug info set and share it between all coroutine clones (PR #118628)
Artem Pianykh via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Tue Dec 10 00:11:10 PST 2024
https://github.com/artempyanykh updated https://github.com/llvm/llvm-project/pull/118628
>From 2a6b745f019393c97b38858ee9427369bbf0feb7 Mon Sep 17 00:00:00 2001
From: Artem Pianykh <arr at fb.com>
Date: Tue, 19 Nov 2024 17:19:27 -0700
Subject: [PATCH] [Coro] Prebuild a module-level debug info set and share it
between all coroutine clones
Summary:
CoroCloner, by calling into CloneFunctionInto, does a lot of repeated
work priming DIFinder and building a list of common module-level debug
info metadata. For programs compiled with full debug info this can get
very expensive.
This diff builds the data once and shares it between all clones.
Anecdata for a sample cpp source file compiled with full debug info:
| | Baseline | IdentityMD set | Prebuilt CommonDI (cur.) |
|-----------------|----------|----------------|--------------------------|
| CoroSplitPass | 306ms | 221ms | 68ms |
| CoroCloner | 101ms | 72ms | 0.5ms |
| CollectGlobalDI | - | - | 63ms |
| Speed up | 1x | 1.4x | 4.5x |
Note that CollectCommonDebugInfo happens once *per coroutine* rather than per clone.
Test Plan:
ninja check-llvm-unit
ninja check-llvm
Compiled a sample internal source file, checked time trace output for scope timings.
stack-info: PR: https://github.com/llvm/llvm-project/pull/118628, branch: users/artempyanykh/fast-coro-upstream/9
---
llvm/lib/Transforms/Coroutines/CoroCloner.h | 31 +++++++-----
llvm/lib/Transforms/Coroutines/CoroSplit.cpp | 50 +++++++++++++++++---
2 files changed, 63 insertions(+), 18 deletions(-)
diff --git a/llvm/lib/Transforms/Coroutines/CoroCloner.h b/llvm/lib/Transforms/Coroutines/CoroCloner.h
index d1887980fb3bcb..b817e55cad9fc3 100644
--- a/llvm/lib/Transforms/Coroutines/CoroCloner.h
+++ b/llvm/lib/Transforms/Coroutines/CoroCloner.h
@@ -48,6 +48,9 @@ class BaseCloner {
CloneKind FKind;
IRBuilder<> Builder;
TargetTransformInfo &TTI;
+ // Common module-level metadata that's shared between all coroutine clones and
+ // doesn't need to be cloned itself.
+ const MetadataSetTy &CommonDebugInfo;
ValueToValueMapTy VMap;
Function *NewF = nullptr;
@@ -60,12 +63,12 @@ class BaseCloner {
/// Create a cloner for a continuation lowering.
BaseCloner(Function &OrigF, const Twine &Suffix, coro::Shape &Shape,
Function *NewF, AnyCoroSuspendInst *ActiveSuspend,
- TargetTransformInfo &TTI)
+ TargetTransformInfo &TTI, const MetadataSetTy &CommonDebugInfo)
: OrigF(OrigF), Suffix(Suffix), Shape(Shape),
FKind(Shape.ABI == ABI::Async ? CloneKind::Async
: CloneKind::Continuation),
- Builder(OrigF.getContext()), TTI(TTI), NewF(NewF),
- ActiveSuspend(ActiveSuspend) {
+ Builder(OrigF.getContext()), TTI(TTI), CommonDebugInfo(CommonDebugInfo),
+ NewF(NewF), ActiveSuspend(ActiveSuspend) {
assert(Shape.ABI == ABI::Retcon || Shape.ABI == ABI::RetconOnce ||
Shape.ABI == ABI::Async);
assert(NewF && "need existing function for continuation");
@@ -74,9 +77,11 @@ class BaseCloner {
public:
BaseCloner(Function &OrigF, const Twine &Suffix, coro::Shape &Shape,
- CloneKind FKind, TargetTransformInfo &TTI)
+ CloneKind FKind, TargetTransformInfo &TTI,
+ const MetadataSetTy &CommonDebugInfo)
: OrigF(OrigF), Suffix(Suffix), Shape(Shape), FKind(FKind),
- Builder(OrigF.getContext()), TTI(TTI) {}
+ Builder(OrigF.getContext()), TTI(TTI),
+ CommonDebugInfo(CommonDebugInfo) {}
virtual ~BaseCloner() {}
@@ -84,12 +89,14 @@ class BaseCloner {
static Function *createClone(Function &OrigF, const Twine &Suffix,
coro::Shape &Shape, Function *NewF,
AnyCoroSuspendInst *ActiveSuspend,
- TargetTransformInfo &TTI) {
+ TargetTransformInfo &TTI,
+ const MetadataSetTy &CommonDebugInfo) {
assert(Shape.ABI == ABI::Retcon || Shape.ABI == ABI::RetconOnce ||
Shape.ABI == ABI::Async);
TimeTraceScope FunctionScope("BaseCloner");
- BaseCloner Cloner(OrigF, Suffix, Shape, NewF, ActiveSuspend, TTI);
+ BaseCloner Cloner(OrigF, Suffix, Shape, NewF, ActiveSuspend, TTI,
+ CommonDebugInfo);
Cloner.create();
return Cloner.getFunction();
}
@@ -129,8 +136,9 @@ class SwitchCloner : public BaseCloner {
protected:
/// Create a cloner for a switch lowering.
SwitchCloner(Function &OrigF, const Twine &Suffix, coro::Shape &Shape,
- CloneKind FKind, TargetTransformInfo &TTI)
- : BaseCloner(OrigF, Suffix, Shape, FKind, TTI) {}
+ CloneKind FKind, TargetTransformInfo &TTI,
+ const MetadataSetTy &CommonDebugInfo)
+ : BaseCloner(OrigF, Suffix, Shape, FKind, TTI, CommonDebugInfo) {}
void create() override;
@@ -138,11 +146,12 @@ class SwitchCloner : public BaseCloner {
/// Create a clone for a switch lowering.
static Function *createClone(Function &OrigF, const Twine &Suffix,
coro::Shape &Shape, CloneKind FKind,
- TargetTransformInfo &TTI) {
+ TargetTransformInfo &TTI,
+ const MetadataSetTy &CommonDebugInfo) {
assert(Shape.ABI == ABI::Switch);
TimeTraceScope FunctionScope("SwitchCloner");
- SwitchCloner Cloner(OrigF, Suffix, Shape, FKind, TTI);
+ SwitchCloner Cloner(OrigF, Suffix, Shape, FKind, TTI, CommonDebugInfo);
Cloner.create();
return Cloner.getFunction();
}
diff --git a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
index 3808147fc26009..377d96bdfae006 100644
--- a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -43,6 +43,7 @@
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/GlobalValue.h"
@@ -77,6 +78,27 @@ using namespace llvm;
#define DEBUG_TYPE "coro-split"
+namespace {
+/// Collect (a known) subset of global debug info metadata potentially used by
+/// the function \p F.
+///
+/// This metadata set can be used to avoid cloning debug info not owned by \p F
+/// and is shared among all potential clones \p F.
+MetadataSetTy collectCommonDebugInfo(Function &F) {
+ TimeTraceScope FunctionScope("CollectCommonDebugInfo");
+
+ MetadataSetTy CommonDebugInfo;
+ DebugInfoFinder DIFinder;
+ DISubprogram *SPClonedWithinModule = CollectDebugInfoForCloning(
+ F, CloneFunctionChangeType::LocalChangesOnly, DIFinder);
+
+ FindDebugInfoToIdentityMap(CommonDebugInfo,
+ CloneFunctionChangeType::LocalChangesOnly,
+ DIFinder, SPClonedWithinModule);
+ return CommonDebugInfo;
+}
+} // end anonymous namespace
+
// FIXME:
// Lower the intrinisc in CoroEarly phase if coroutine frame doesn't escape
// and it is known that other transformations, for example, sanitizers
@@ -891,8 +913,11 @@ void coro::BaseCloner::create() {
auto savedLinkage = NewF->getLinkage();
NewF->setLinkage(llvm::GlobalValue::ExternalLinkage);
- CloneFunctionInto(NewF, &OrigF, VMap,
- CloneFunctionChangeType::LocalChangesOnly, Returns);
+ CloneFunctionAttributesInto(NewF, &OrigF, VMap, false);
+ CloneFunctionMetadataInto(NewF, &OrigF, VMap, RF_None, nullptr, nullptr,
+ &CommonDebugInfo);
+ CloneFunctionBodyInto(NewF, &OrigF, VMap, RF_None, Returns, "", nullptr,
+ nullptr, nullptr, &CommonDebugInfo);
auto &Context = NewF->getContext();
@@ -1374,16 +1399,21 @@ struct SwitchCoroutineSplitter {
TargetTransformInfo &TTI) {
assert(Shape.ABI == coro::ABI::Switch);
+ MetadataSetTy CommonDebugInfo{collectCommonDebugInfo(F)};
+
// Create a resume clone by cloning the body of the original function,
// setting new entry block and replacing coro.suspend an appropriate value
// to force resume or cleanup pass for every suspend point.
createResumeEntryBlock(F, Shape);
auto *ResumeClone = coro::SwitchCloner::createClone(
- F, ".resume", Shape, coro::CloneKind::SwitchResume, TTI);
+ F, ".resume", Shape, coro::CloneKind::SwitchResume, TTI,
+ CommonDebugInfo);
auto *DestroyClone = coro::SwitchCloner::createClone(
- F, ".destroy", Shape, coro::CloneKind::SwitchUnwind, TTI);
+ F, ".destroy", Shape, coro::CloneKind::SwitchUnwind, TTI,
+ CommonDebugInfo);
auto *CleanupClone = coro::SwitchCloner::createClone(
- F, ".cleanup", Shape, coro::CloneKind::SwitchCleanup, TTI);
+ F, ".cleanup", Shape, coro::CloneKind::SwitchCleanup, TTI,
+ CommonDebugInfo);
postSplitCleanup(*ResumeClone);
postSplitCleanup(*DestroyClone);
@@ -1768,12 +1798,15 @@ void coro::AsyncABI::splitCoroutine(Function &F, coro::Shape &Shape,
}
assert(Clones.size() == Shape.CoroSuspends.size());
+
+ MetadataSetTy CommonDebugInfo{collectCommonDebugInfo(F)};
+
for (auto [Idx, CS] : llvm::enumerate(Shape.CoroSuspends)) {
auto *Suspend = CS;
auto *Clone = Clones[Idx];
coro::BaseCloner::createClone(F, "resume." + Twine(Idx), Shape, Clone,
- Suspend, TTI);
+ Suspend, TTI, CommonDebugInfo);
}
}
@@ -1899,12 +1932,15 @@ void coro::AnyRetconABI::splitCoroutine(Function &F, coro::Shape &Shape,
}
assert(Clones.size() == Shape.CoroSuspends.size());
+
+ MetadataSetTy CommonDebugInfo{collectCommonDebugInfo(F)};
+
for (auto [Idx, CS] : llvm::enumerate(Shape.CoroSuspends)) {
auto Suspend = CS;
auto Clone = Clones[Idx];
coro::BaseCloner::createClone(F, "resume." + Twine(Idx), Shape, Clone,
- Suspend, TTI);
+ Suspend, TTI, CommonDebugInfo);
}
}
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