[llvm] [Coro] Prebuild a module-level debug info set and share it between all coroutine clones (PR #118628)
Artem Pianykh via llvm-commits
llvm-commits at lists.llvm.org
Tue Dec 10 23:48:43 PST 2024
https://github.com/artempyanykh updated https://github.com/llvm/llvm-project/pull/118628
>From a91e78306754e84ee8a3db320e52d0cf9d347bb6 Mon Sep 17 00:00:00 2001
From: Artem Pianykh <arr at fb.com>
Date: Thu, 12 Sep 2024 15:35:38 -0700
Subject: [PATCH 1/5] [NFC][Utils] Extract CloneFunctionMetadataInto from
CloneFunctionInto
Summary:
The new API expects the caller to populate the VMap. We need it this way
for a subsequent change around coroutine cloning.
Test Plan:
ninja check-llvm-unit check-llvm
stack-info: PR: https://github.com/llvm/llvm-project/pull/118623, branch: users/artempyanykh/fast-coro-upstream/4
---
llvm/include/llvm/Transforms/Utils/Cloning.h | 13 ++++++++++
llvm/lib/Transforms/Utils/CloneFunction.cpp | 25 +++++++++++++-------
2 files changed, 29 insertions(+), 9 deletions(-)
diff --git a/llvm/include/llvm/Transforms/Utils/Cloning.h b/llvm/include/llvm/Transforms/Utils/Cloning.h
index 7858c9d9def0da..06f21c236a1649 100644
--- a/llvm/include/llvm/Transforms/Utils/Cloning.h
+++ b/llvm/include/llvm/Transforms/Utils/Cloning.h
@@ -182,6 +182,19 @@ void CloneFunctionAttributesInto(Function *NewFunc, const Function *OldFunc,
ValueMapTypeRemapper *TypeMapper = nullptr,
ValueMaterializer *Materializer = nullptr);
+/// Clone OldFunc's metadata into NewFunc.
+///
+/// The caller is expected to populate \p VMap beforehand and set an appropriate
+/// \p RemapFlag. Subprograms/CUs/types that were already mapped to themselves
+/// won't be duplicated.
+///
+/// NOTE: This function doesn't clone !llvm.dbg.cu when cloning into a different
+/// module. Use CloneFunctionInto for that behavior.
+void CloneFunctionMetadataInto(Function &NewFunc, const Function &OldFunc,
+ ValueToValueMapTy &VMap, RemapFlags RemapFlag,
+ ValueMapTypeRemapper *TypeMapper = nullptr,
+ ValueMaterializer *Materializer = nullptr);
+
void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
const Instruction *StartingInst,
ValueToValueMapTy &VMap, bool ModuleLevelChanges,
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 6dc5f601b7fcaa..8b3070027aa548 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -200,6 +200,19 @@ bool llvm::BuildDebugInfoMDMap(DenseMap<const Metadata *, TrackingMDRef> &MD,
return ModuleLevelChanges;
}
+void llvm::CloneFunctionMetadataInto(Function &NewFunc, const Function &OldFunc,
+ ValueToValueMapTy &VMap,
+ RemapFlags RemapFlag,
+ ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer) {
+ SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
+ OldFunc.getAllMetadata(MDs);
+ for (auto MD : MDs) {
+ NewFunc.addMetadata(MD.first, *MapMetadata(MD.second, VMap, RemapFlag,
+ TypeMapper, Materializer));
+ }
+}
+
// Clone OldFunc into NewFunc, transforming the old arguments into references to
// VMap values.
void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
@@ -262,15 +275,9 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
BuildDebugInfoMDMap(VMap.MD(), Changes, DIFinder, SPClonedWithinModule);
const auto RemapFlag = ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges;
- // Duplicate the metadata that is attached to the cloned function.
- // Subprograms/CUs/types that were already mapped to themselves won't be
- // duplicated.
- SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
- OldFunc->getAllMetadata(MDs);
- for (auto MD : MDs) {
- NewFunc->addMetadata(MD.first, *MapMetadata(MD.second, VMap, RemapFlag,
- TypeMapper, Materializer));
- }
+
+ CloneFunctionMetadataInto(*NewFunc, *OldFunc, VMap, RemapFlag, TypeMapper,
+ Materializer);
// Loop over all of the basic blocks in the function, cloning them as
// appropriate. Note that we save BE this way in order to handle cloning of
>From 1560bb07cb0c9ba43da6b99c472f93c72ea369f2 Mon Sep 17 00:00:00 2001
From: Artem Pyanykh <artem.pyanykh at gmail.com>
Date: Wed, 11 Dec 2024 07:23:08 +0000
Subject: [PATCH 2/5] [NFC][Utils] Extract CloneFunctionBodyInto from
CloneFunctionInto
Summary:
This and previously extracted `CloneFunction*Into` functions will be used in later diffs.
Test Plan:
ninja check-llvm-unit check-llvm
stack-info: PR: https://github.com/llvm/llvm-project/pull/118624, branch: users/artempyanykh/fast-coro-upstream/5
---
llvm/include/llvm/Transforms/Utils/Cloning.h | 9 ++
llvm/lib/Transforms/Utils/CloneFunction.cpp | 97 +++++++++++---------
2 files changed, 65 insertions(+), 41 deletions(-)
diff --git a/llvm/include/llvm/Transforms/Utils/Cloning.h b/llvm/include/llvm/Transforms/Utils/Cloning.h
index 06f21c236a1649..2fcb64206387ed 100644
--- a/llvm/include/llvm/Transforms/Utils/Cloning.h
+++ b/llvm/include/llvm/Transforms/Utils/Cloning.h
@@ -195,6 +195,15 @@ void CloneFunctionMetadataInto(Function &NewFunc, const Function &OldFunc,
ValueMapTypeRemapper *TypeMapper = nullptr,
ValueMaterializer *Materializer = nullptr);
+/// Clone OldFunc's body into NewFunc.
+void CloneFunctionBodyInto(Function &NewFunc, const Function &OldFunc,
+ ValueToValueMapTy &VMap, RemapFlags RemapFlag,
+ SmallVectorImpl<ReturnInst *> &Returns,
+ const char *NameSuffix = "",
+ ClonedCodeInfo *CodeInfo = nullptr,
+ ValueMapTypeRemapper *TypeMapper = nullptr,
+ ValueMaterializer *Materializer = nullptr);
+
void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
const Instruction *StartingInst,
ValueToValueMapTy &VMap, bool ModuleLevelChanges,
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 8b3070027aa548..d47633a05fce96 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -213,6 +213,60 @@ void llvm::CloneFunctionMetadataInto(Function &NewFunc, const Function &OldFunc,
}
}
+void llvm::CloneFunctionBodyInto(Function &NewFunc, const Function &OldFunc,
+ ValueToValueMapTy &VMap, RemapFlags RemapFlag,
+ SmallVectorImpl<ReturnInst *> &Returns,
+ const char *NameSuffix,
+ ClonedCodeInfo *CodeInfo,
+ ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer) {
+ if (OldFunc.isDeclaration())
+ return;
+
+ // Loop over all of the basic blocks in the function, cloning them as
+ // appropriate. Note that we save BE this way in order to handle cloning of
+ // recursive functions into themselves.
+ for (const BasicBlock &BB : OldFunc) {
+
+ // Create a new basic block and copy instructions into it!
+ BasicBlock *CBB =
+ CloneBasicBlock(&BB, VMap, NameSuffix, &NewFunc, CodeInfo);
+
+ // Add basic block mapping.
+ VMap[&BB] = CBB;
+
+ // It is only legal to clone a function if a block address within that
+ // function is never referenced outside of the function. Given that, we
+ // want to map block addresses from the old function to block addresses in
+ // the clone. (This is different from the generic ValueMapper
+ // implementation, which generates an invalid blockaddress when
+ // cloning a function.)
+ if (BB.hasAddressTaken()) {
+ Constant *OldBBAddr = BlockAddress::get(const_cast<Function *>(&OldFunc),
+ const_cast<BasicBlock *>(&BB));
+ VMap[OldBBAddr] = BlockAddress::get(&NewFunc, CBB);
+ }
+
+ // Note return instructions for the caller.
+ if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator()))
+ Returns.push_back(RI);
+ }
+
+ // Loop over all of the instructions in the new function, fixing up operand
+ // references as we go. This uses VMap to do all the hard work.
+ for (Function::iterator
+ BB = cast<BasicBlock>(VMap[&OldFunc.front()])->getIterator(),
+ BE = NewFunc.end();
+ BB != BE; ++BB)
+ // Loop over all instructions, fixing each one as we find it, and any
+ // attached debug-info records.
+ for (Instruction &II : *BB) {
+ RemapInstruction(&II, VMap, RemapFlag, TypeMapper, Materializer);
+ RemapDbgRecordRange(II.getModule(), II.getDbgRecordRange(), VMap,
+ RemapFlag, TypeMapper, Materializer);
+ }
+}
+
// Clone OldFunc into NewFunc, transforming the old arguments into references to
// VMap values.
void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
@@ -279,47 +333,8 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
CloneFunctionMetadataInto(*NewFunc, *OldFunc, VMap, RemapFlag, TypeMapper,
Materializer);
- // Loop over all of the basic blocks in the function, cloning them as
- // appropriate. Note that we save BE this way in order to handle cloning of
- // recursive functions into themselves.
- for (const BasicBlock &BB : *OldFunc) {
-
- // Create a new basic block and copy instructions into it!
- BasicBlock *CBB = CloneBasicBlock(&BB, VMap, NameSuffix, NewFunc, CodeInfo);
-
- // Add basic block mapping.
- VMap[&BB] = CBB;
-
- // It is only legal to clone a function if a block address within that
- // function is never referenced outside of the function. Given that, we
- // want to map block addresses from the old function to block addresses in
- // the clone. (This is different from the generic ValueMapper
- // implementation, which generates an invalid blockaddress when
- // cloning a function.)
- if (BB.hasAddressTaken()) {
- Constant *OldBBAddr = BlockAddress::get(const_cast<Function *>(OldFunc),
- const_cast<BasicBlock *>(&BB));
- VMap[OldBBAddr] = BlockAddress::get(NewFunc, CBB);
- }
-
- // Note return instructions for the caller.
- if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator()))
- Returns.push_back(RI);
- }
-
- // Loop over all of the instructions in the new function, fixing up operand
- // references as we go. This uses VMap to do all the hard work.
- for (Function::iterator
- BB = cast<BasicBlock>(VMap[&OldFunc->front()])->getIterator(),
- BE = NewFunc->end();
- BB != BE; ++BB)
- // Loop over all instructions, fixing each one as we find it, and any
- // attached debug-info records.
- for (Instruction &II : *BB) {
- RemapInstruction(&II, VMap, RemapFlag, TypeMapper, Materializer);
- RemapDbgRecordRange(II.getModule(), II.getDbgRecordRange(), VMap,
- RemapFlag, TypeMapper, Materializer);
- }
+ CloneFunctionBodyInto(*NewFunc, *OldFunc, VMap, RemapFlag, Returns,
+ NameSuffix, CodeInfo, TypeMapper, Materializer);
// Only update !llvm.dbg.cu for DifferentModule (not CloneModule). In the
// same module, the compile unit will already be listed (or not). When
>From b5d377b693b0860420dfbb8fbf747e04d9cb7594 Mon Sep 17 00:00:00 2001
From: Artem Pianykh <arr at fb.com>
Date: Sat, 14 Sep 2024 16:02:51 -0700
Subject: [PATCH 3/5] [NFC][Utils] Eliminate DISubprogram set from
BuildDebugInfoMDMap
Summary:
Previously, we'd add all SPs distinct from the cloned one into a set.
Then when cloning a local scope we'd check if it's from one of those
'distinct' SPs by checking if it's in the set. We don't need to do that.
We can just check against the cloned SP directly and drop the set.
Test Plan:
ninja check-llvm-unit check-llvm
stack-info: PR: https://github.com/llvm/llvm-project/pull/118625, branch: users/artempyanykh/fast-coro-upstream/6
---
llvm/lib/Transforms/Utils/CloneFunction.cpp | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index d47633a05fce96..8863dff4482a1a 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -172,18 +172,15 @@ bool llvm::BuildDebugInfoMDMap(DenseMap<const Metadata *, TrackingMDRef> &MD,
};
// Avoid cloning types, compile units, and (other) subprograms.
- SmallPtrSet<const DISubprogram *, 16> MappedToSelfSPs;
for (DISubprogram *ISP : DIFinder.subprograms()) {
- if (ISP != SPClonedWithinModule) {
+ if (ISP != SPClonedWithinModule)
mapToSelfIfNew(ISP);
- MappedToSelfSPs.insert(ISP);
- }
}
// If a subprogram isn't going to be cloned skip its lexical blocks as well.
for (DIScope *S : DIFinder.scopes()) {
auto *LScope = dyn_cast<DILocalScope>(S);
- if (LScope && MappedToSelfSPs.count(LScope->getSubprogram()))
+ if (LScope && LScope->getSubprogram() != SPClonedWithinModule)
mapToSelfIfNew(S);
}
>From 28527bcb6f5cba1850f10d0f7866e2267fed7d34 Mon Sep 17 00:00:00 2001
From: Artem Pianykh <arr at fb.com>
Date: Sun, 15 Sep 2024 04:39:20 -0700
Subject: [PATCH 4/5] [Utils] Identity map module-level debug info on first use
in CloneFunction*
Summary:
To avoid cloning module-level debug info (owned by the module rather
than the function), CloneFunction implementation used to eagerly
identity map such debug info into ValueMap's MD map. In larger modules
with meaningful volume of debug info this gets very expensive.
By passing such debug info metadata via an IdentityMD set for the
ValueMapper to map on first use, we get several benefits:
1. Mapping metadata is not cheap, particularly because of tracking. When
cloning a Function we identity map lots of global module-level
metadata to avoid cloning it, while only a fraction of it is actually
used by the function. Mapping on first use is a lot faster for
modules with meaningful amount of debug info.
2. Eagerly identity mapping metadata makes it harder to cache
module-level data (e.g. a set of metadata nodes in a \a DICompileUnit).
With this patch we can cache certain module-level metadata
calculations to speed things up further.
Anecdata from compiling a sample cpp file with full debug info shows that this moderately speeds up
CoroSplitPass which is one of the heavier users of cloning:
| | Baseline | IdentityMD set |
|-----------------|----------|----------------|
| CoroSplitPass | 306ms | 221ms |
| CoroCloner | 101ms | 72ms |
| Speed up | 1x | 1.4x |
Test Plan:
ninja check-llvm-unit
ninja check-llvm
stack-info: PR: https://github.com/llvm/llvm-project/pull/118627, branch: users/artempyanykh/fast-coro-upstream/8
---
llvm/include/llvm/Transforms/Utils/Cloning.h | 19 +++---
.../llvm/Transforms/Utils/ValueMapper.h | 67 ++++++++++++++-----
llvm/lib/Transforms/Utils/CloneFunction.cpp | 60 ++++++++---------
llvm/lib/Transforms/Utils/ValueMapper.cpp | 19 ++++--
4 files changed, 104 insertions(+), 61 deletions(-)
diff --git a/llvm/include/llvm/Transforms/Utils/Cloning.h b/llvm/include/llvm/Transforms/Utils/Cloning.h
index 2fcb64206387ed..72d3eebabc5c9a 100644
--- a/llvm/include/llvm/Transforms/Utils/Cloning.h
+++ b/llvm/include/llvm/Transforms/Utils/Cloning.h
@@ -193,7 +193,8 @@ void CloneFunctionAttributesInto(Function *NewFunc, const Function *OldFunc,
void CloneFunctionMetadataInto(Function &NewFunc, const Function &OldFunc,
ValueToValueMapTy &VMap, RemapFlags RemapFlag,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr);
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr);
/// Clone OldFunc's body into NewFunc.
void CloneFunctionBodyInto(Function &NewFunc, const Function &OldFunc,
@@ -202,7 +203,8 @@ void CloneFunctionBodyInto(Function &NewFunc, const Function &OldFunc,
const char *NameSuffix = "",
ClonedCodeInfo *CodeInfo = nullptr,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr);
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr);
void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
const Instruction *StartingInst,
@@ -242,13 +244,12 @@ DISubprogram *CollectDebugInfoForCloning(const Function &F,
CloneFunctionChangeType Changes,
DebugInfoFinder &DIFinder);
-/// Build a map of debug info to use during Metadata cloning.
-/// Returns true if cloning would need module level changes and false if there
-/// would only be local changes.
-bool BuildDebugInfoMDMap(DenseMap<const Metadata *, TrackingMDRef> &MD,
- CloneFunctionChangeType Changes,
- DebugInfoFinder &DIFinder,
- DISubprogram *SPClonedWithinModule);
+/// Based on \p Changes and \p DIFinder populate \p MD with debug info that
+/// needs to be identity mapped during Metadata cloning.
+void FindDebugInfoToIdentityMap(MetadataSetTy &MD,
+ CloneFunctionChangeType Changes,
+ DebugInfoFinder &DIFinder,
+ DISubprogram *SPClonedWithinModule);
/// This class captures the data input to the InlineFunction call, and records
/// the auxiliary results produced by it.
diff --git a/llvm/include/llvm/Transforms/Utils/ValueMapper.h b/llvm/include/llvm/Transforms/Utils/ValueMapper.h
index 743cfeb7ef3f02..b8d612f11d519f 100644
--- a/llvm/include/llvm/Transforms/Utils/ValueMapper.h
+++ b/llvm/include/llvm/Transforms/Utils/ValueMapper.h
@@ -15,6 +15,7 @@
#define LLVM_TRANSFORMS_UTILS_VALUEMAPPER_H
#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/simple_ilist.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/IR/ValueMap.h"
@@ -35,6 +36,7 @@ class Value;
using ValueToValueMapTy = ValueMap<const Value *, WeakTrackingVH>;
using DbgRecordIterator = simple_ilist<DbgRecord>::iterator;
+using MetadataSetTy = SmallPtrSet<const Metadata *, 16>;
/// This is a class that can be implemented by clients to remap types when
/// cloning constants and instructions.
@@ -136,6 +138,18 @@ inline RemapFlags operator|(RemapFlags LHS, RemapFlags RHS) {
/// alternate \a ValueToValueMapTy and \a ValueMaterializer and returns a ID to
/// pass into the schedule*() functions.
///
+/// NOTE: \c IdentityMD is used by CloneFunction* to directly specify metadata
+/// that should be identity mapped (and hence not cloned). The metadata will be
+/// identity mapped in \c VM on first use. There are several reasons for doing
+/// it this way rather than eagerly identity mapping metadata nodes in \c VM:
+/// 1. Mapping metadata is not cheap, particularly because of tracking.
+/// 2. When cloning a Function we identity map lots of global module-level
+/// metadata to avoid cloning it, while only a fraction of it is actually
+/// used by the function. Mapping on first use is a lot faster for modules
+/// with meaningful amount of debug info.
+/// 3. Eagerly identity mapping metadata makes it harder to cache module-level
+/// data (e.g. a set of metadata nodes in a \a DICompileUnit).
+///
/// TODO: lib/Linker really doesn't need the \a ValueHandle in the \a
/// ValueToValueMapTy. We should template \a ValueMapper (and its
/// implementation classes), and explicitly instantiate on two concrete
@@ -152,7 +166,8 @@ class ValueMapper {
public:
ValueMapper(ValueToValueMapTy &VM, RemapFlags Flags = RF_None,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr);
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr);
ValueMapper(ValueMapper &&) = delete;
ValueMapper(const ValueMapper &) = delete;
ValueMapper &operator=(ValueMapper &&) = delete;
@@ -218,8 +233,10 @@ class ValueMapper {
inline Value *MapValue(const Value *V, ValueToValueMapTy &VM,
RemapFlags Flags = RF_None,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr) {
- return ValueMapper(VM, Flags, TypeMapper, Materializer).mapValue(*V);
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr) {
+ return ValueMapper(VM, Flags, TypeMapper, Materializer, IdentityMD)
+ .mapValue(*V);
}
/// Lookup or compute a mapping for a piece of metadata.
@@ -231,7 +248,9 @@ inline Value *MapValue(const Value *V, ValueToValueMapTy &VM,
/// \c MD.
/// 3. Else if \c MD is a \a ConstantAsMetadata, call \a MapValue() and
/// re-wrap its return (returning nullptr on nullptr).
-/// 4. Else, \c MD is an \a MDNode. These are remapped, along with their
+/// 4. Else if \c MD is in \c IdentityMD then add an identity mapping for it
+/// and return it.
+/// 5. Else, \c MD is an \a MDNode. These are remapped, along with their
/// transitive operands. Distinct nodes are duplicated or moved depending
/// on \a RF_MoveDistinctNodes. Uniqued nodes are remapped like constants.
///
@@ -240,16 +259,20 @@ inline Value *MapValue(const Value *V, ValueToValueMapTy &VM,
inline Metadata *MapMetadata(const Metadata *MD, ValueToValueMapTy &VM,
RemapFlags Flags = RF_None,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr) {
- return ValueMapper(VM, Flags, TypeMapper, Materializer).mapMetadata(*MD);
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr) {
+ return ValueMapper(VM, Flags, TypeMapper, Materializer, IdentityMD)
+ .mapMetadata(*MD);
}
/// Version of MapMetadata with type safety for MDNode.
inline MDNode *MapMetadata(const MDNode *MD, ValueToValueMapTy &VM,
RemapFlags Flags = RF_None,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr) {
- return ValueMapper(VM, Flags, TypeMapper, Materializer).mapMDNode(*MD);
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr) {
+ return ValueMapper(VM, Flags, TypeMapper, Materializer, IdentityMD)
+ .mapMDNode(*MD);
}
/// Convert the instruction operands from referencing the current values into
@@ -263,8 +286,10 @@ inline MDNode *MapMetadata(const MDNode *MD, ValueToValueMapTy &VM,
inline void RemapInstruction(Instruction *I, ValueToValueMapTy &VM,
RemapFlags Flags = RF_None,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr) {
- ValueMapper(VM, Flags, TypeMapper, Materializer).remapInstruction(*I);
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr) {
+ ValueMapper(VM, Flags, TypeMapper, Materializer, IdentityMD)
+ .remapInstruction(*I);
}
/// Remap the Values used in the DbgRecord \a DR using the value map \a
@@ -272,8 +297,10 @@ inline void RemapInstruction(Instruction *I, ValueToValueMapTy &VM,
inline void RemapDbgRecord(Module *M, DbgRecord *DR, ValueToValueMapTy &VM,
RemapFlags Flags = RF_None,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr) {
- ValueMapper(VM, Flags, TypeMapper, Materializer).remapDbgRecord(M, *DR);
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr) {
+ ValueMapper(VM, Flags, TypeMapper, Materializer, IdentityMD)
+ .remapDbgRecord(M, *DR);
}
/// Remap the Values used in the DbgRecords \a Range using the value map \a
@@ -283,8 +310,9 @@ inline void RemapDbgRecordRange(Module *M,
ValueToValueMapTy &VM,
RemapFlags Flags = RF_None,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr) {
- ValueMapper(VM, Flags, TypeMapper, Materializer)
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr) {
+ ValueMapper(VM, Flags, TypeMapper, Materializer, IdentityMD)
.remapDbgRecordRange(M, Range);
}
@@ -297,16 +325,19 @@ inline void RemapDbgRecordRange(Module *M,
inline void RemapFunction(Function &F, ValueToValueMapTy &VM,
RemapFlags Flags = RF_None,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr) {
- ValueMapper(VM, Flags, TypeMapper, Materializer).remapFunction(F);
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr) {
+ ValueMapper(VM, Flags, TypeMapper, Materializer, IdentityMD).remapFunction(F);
}
/// Version of MapValue with type safety for Constant.
inline Constant *MapValue(const Constant *V, ValueToValueMapTy &VM,
RemapFlags Flags = RF_None,
ValueMapTypeRemapper *TypeMapper = nullptr,
- ValueMaterializer *Materializer = nullptr) {
- return ValueMapper(VM, Flags, TypeMapper, Materializer).mapConstant(*V);
+ ValueMaterializer *Materializer = nullptr,
+ const MetadataSetTy *IdentityMD = nullptr) {
+ return ValueMapper(VM, Flags, TypeMapper, Materializer, IdentityMD)
+ .mapConstant(*V);
}
} // end namespace llvm
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 8863dff4482a1a..a962d017c73998 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -152,61 +152,54 @@ DISubprogram *llvm::CollectDebugInfoForCloning(const Function &F,
return SPClonedWithinModule;
}
-bool llvm::BuildDebugInfoMDMap(DenseMap<const Metadata *, TrackingMDRef> &MD,
- CloneFunctionChangeType Changes,
- DebugInfoFinder &DIFinder,
- DISubprogram *SPClonedWithinModule) {
- bool ModuleLevelChanges = Changes > CloneFunctionChangeType::LocalChangesOnly;
+void llvm::FindDebugInfoToIdentityMap(MetadataSetTy &MD,
+ CloneFunctionChangeType Changes,
+ DebugInfoFinder &DIFinder,
+ DISubprogram *SPClonedWithinModule) {
if (Changes < CloneFunctionChangeType::DifferentModule &&
DIFinder.subprogram_count() > 0) {
- // Turn on module-level changes, since we need to clone (some of) the
- // debug info metadata.
+ // Even if Changes are local only, we turn on module-level changes, since we
+ // need to clone (some of) the debug info metadata.
//
// FIXME: Metadata effectively owned by a function should be made
// local, and only that local metadata should be cloned.
- ModuleLevelChanges = true;
-
- auto mapToSelfIfNew = [&MD](MDNode *N) {
- // Avoid clobbering an existing mapping.
- (void)MD.try_emplace(N, N);
- };
// Avoid cloning types, compile units, and (other) subprograms.
for (DISubprogram *ISP : DIFinder.subprograms()) {
if (ISP != SPClonedWithinModule)
- mapToSelfIfNew(ISP);
+ MD.insert(ISP);
}
// If a subprogram isn't going to be cloned skip its lexical blocks as well.
for (DIScope *S : DIFinder.scopes()) {
auto *LScope = dyn_cast<DILocalScope>(S);
if (LScope && LScope->getSubprogram() != SPClonedWithinModule)
- mapToSelfIfNew(S);
+ MD.insert(S);
}
for (DICompileUnit *CU : DIFinder.compile_units())
- mapToSelfIfNew(CU);
+ MD.insert(CU);
for (DIType *Type : DIFinder.types())
- mapToSelfIfNew(Type);
+ MD.insert(Type);
} else {
assert(!SPClonedWithinModule &&
"Subprogram should be in DIFinder->subprogram_count()...");
}
-
- return ModuleLevelChanges;
}
void llvm::CloneFunctionMetadataInto(Function &NewFunc, const Function &OldFunc,
ValueToValueMapTy &VMap,
RemapFlags RemapFlag,
ValueMapTypeRemapper *TypeMapper,
- ValueMaterializer *Materializer) {
+ ValueMaterializer *Materializer,
+ const MetadataSetTy *IdentityMD) {
SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
OldFunc.getAllMetadata(MDs);
for (auto MD : MDs) {
- NewFunc.addMetadata(MD.first, *MapMetadata(MD.second, VMap, RemapFlag,
- TypeMapper, Materializer));
+ NewFunc.addMetadata(MD.first,
+ *MapMetadata(MD.second, VMap, RemapFlag, TypeMapper,
+ Materializer, IdentityMD));
}
}
@@ -216,7 +209,8 @@ void llvm::CloneFunctionBodyInto(Function &NewFunc, const Function &OldFunc,
const char *NameSuffix,
ClonedCodeInfo *CodeInfo,
ValueMapTypeRemapper *TypeMapper,
- ValueMaterializer *Materializer) {
+ ValueMaterializer *Materializer,
+ const MetadataSetTy *IdentityMD) {
if (OldFunc.isDeclaration())
return;
@@ -258,9 +252,10 @@ void llvm::CloneFunctionBodyInto(Function &NewFunc, const Function &OldFunc,
// Loop over all instructions, fixing each one as we find it, and any
// attached debug-info records.
for (Instruction &II : *BB) {
- RemapInstruction(&II, VMap, RemapFlag, TypeMapper, Materializer);
+ RemapInstruction(&II, VMap, RemapFlag, TypeMapper, Materializer,
+ IdentityMD);
RemapDbgRecordRange(II.getModule(), II.getDbgRecordRange(), VMap,
- RemapFlag, TypeMapper, Materializer);
+ RemapFlag, TypeMapper, Materializer, IdentityMD);
}
}
@@ -322,16 +317,21 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
DISubprogram *SPClonedWithinModule =
CollectDebugInfoForCloning(*OldFunc, Changes, DIFinder);
- ModuleLevelChanges =
- BuildDebugInfoMDMap(VMap.MD(), Changes, DIFinder, SPClonedWithinModule);
+ MetadataSetTy IdentityMD;
+ FindDebugInfoToIdentityMap(IdentityMD, Changes, DIFinder,
+ SPClonedWithinModule);
- const auto RemapFlag = ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges;
+ // Current implementation always upgrades from local changes to module level
+ // changes due to the way metadata cloning is done. See
+ // BuildDebugInfoToIdentityMap for more details.
+ const auto RemapFlag = RF_None;
CloneFunctionMetadataInto(*NewFunc, *OldFunc, VMap, RemapFlag, TypeMapper,
- Materializer);
+ Materializer, &IdentityMD);
CloneFunctionBodyInto(*NewFunc, *OldFunc, VMap, RemapFlag, Returns,
- NameSuffix, CodeInfo, TypeMapper, Materializer);
+ NameSuffix, CodeInfo, TypeMapper, Materializer,
+ &IdentityMD);
// Only update !llvm.dbg.cu for DifferentModule (not CloneModule). In the
// same module, the compile unit will already be listed (or not). When
diff --git a/llvm/lib/Transforms/Utils/ValueMapper.cpp b/llvm/lib/Transforms/Utils/ValueMapper.cpp
index 3faea48466ba9d..f6ab5bd284597a 100644
--- a/llvm/lib/Transforms/Utils/ValueMapper.cpp
+++ b/llvm/lib/Transforms/Utils/ValueMapper.cpp
@@ -120,12 +120,14 @@ class Mapper {
SmallVector<WorklistEntry, 4> Worklist;
SmallVector<DelayedBasicBlock, 1> DelayedBBs;
SmallVector<Constant *, 16> AppendingInits;
+ const MetadataSetTy *IdentityMD;
public:
Mapper(ValueToValueMapTy &VM, RemapFlags Flags,
- ValueMapTypeRemapper *TypeMapper, ValueMaterializer *Materializer)
+ ValueMapTypeRemapper *TypeMapper, ValueMaterializer *Materializer,
+ const MetadataSetTy *IdentityMD)
: Flags(Flags), TypeMapper(TypeMapper),
- MCs(1, MappingContext(VM, Materializer)) {}
+ MCs(1, MappingContext(VM, Materializer)), IdentityMD(IdentityMD) {}
/// ValueMapper should explicitly call \a flush() before destruction.
~Mapper() { assert(!hasWorkToDo() && "Expected to be flushed"); }
@@ -899,6 +901,14 @@ std::optional<Metadata *> Mapper::mapSimpleMetadata(const Metadata *MD) {
return wrapConstantAsMetadata(*CMD, mapValue(CMD->getValue()));
}
+ // Map metadata from IdentityMD on first use. We need to add these nodes to
+ // the mapping as otherwise metadata nodes numbering gets messed up. This is
+ // still economical because the amount of data in IdentityMD may be a lot
+ // larger than what will actually get used.
+ if (IdentityMD && IdentityMD->contains(MD)) {
+ return getVM().MD()[MD] = TrackingMDRef(const_cast<Metadata *>(MD));
+ }
+
assert(isa<MDNode>(MD) && "Expected a metadata node");
return std::nullopt;
@@ -1198,8 +1208,9 @@ class FlushingMapper {
ValueMapper::ValueMapper(ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
- ValueMaterializer *Materializer)
- : pImpl(new Mapper(VM, Flags, TypeMapper, Materializer)) {}
+ ValueMaterializer *Materializer,
+ const MetadataSetTy *IdentityMD)
+ : pImpl(new Mapper(VM, Flags, TypeMapper, Materializer, IdentityMD)) {}
ValueMapper::~ValueMapper() { delete getAsMapper(pImpl); }
>From 77e60668e46dc980f5862680a0fce9ff11c27af6 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 5/5] [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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