[llvm] eb51dd7 - [Coroutine] [Debug] Insert dbg.declare to entry.resume to print alloca in the coroutine frame under O2
Chuanqi Xu via llvm-commits
llvm-commits at lists.llvm.org
Tue Mar 30 19:38:09 PDT 2021
Author: Chuanqi Xu
Date: 2021-03-31T10:37:06+08:00
New Revision: eb51dd719f34be09d21b1ef485edc4209fcf811b
URL: https://github.com/llvm/llvm-project/commit/eb51dd719f34be09d21b1ef485edc4209fcf811b
DIFF: https://github.com/llvm/llvm-project/commit/eb51dd719f34be09d21b1ef485edc4209fcf811b.diff
LOG: [Coroutine] [Debug] Insert dbg.declare to entry.resume to print alloca in the coroutine frame under O2
Summary: Try to insert dbg.declare to entry.resume basic block in resume
function. In this way, we could print alloca such as __promise in
gdb/lldb under O2, which would be beneficial to debug coroutine program.
Test Plan: check-llvm
Reviewed by: aprantl
Differential Revision: https://reviews.llvm.org/D96938
Added:
llvm/test/Transforms/Coroutines/coro-debug-O2.ll
Modified:
llvm/include/llvm/Transforms/Coroutines.h
llvm/include/llvm/Transforms/Coroutines/CoroSplit.h
llvm/lib/Transforms/Coroutines/CoroFrame.cpp
llvm/lib/Transforms/Coroutines/CoroInternal.h
llvm/lib/Transforms/Coroutines/CoroSplit.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/Transforms/Coroutines.h b/llvm/include/llvm/Transforms/Coroutines.h
index 204359254d4e8..f68ef705fdef3 100644
--- a/llvm/include/llvm/Transforms/Coroutines.h
+++ b/llvm/include/llvm/Transforms/Coroutines.h
@@ -23,7 +23,7 @@ void addCoroutinePassesToExtensionPoints(PassManagerBuilder &Builder);
Pass *createCoroEarlyLegacyPass();
/// Split up coroutines into multiple functions driving their state machines.
-Pass *createCoroSplitLegacyPass(bool ReuseFrameSlot = false);
+Pass *createCoroSplitLegacyPass(bool IsOptimizing = false);
/// Analyze coroutines use sites, devirtualize resume/destroy calls and elide
/// heap allocation for coroutine frame where possible.
diff --git a/llvm/include/llvm/Transforms/Coroutines/CoroSplit.h b/llvm/include/llvm/Transforms/Coroutines/CoroSplit.h
index f4eef19b20e58..ffca515785518 100644
--- a/llvm/include/llvm/Transforms/Coroutines/CoroSplit.h
+++ b/llvm/include/llvm/Transforms/Coroutines/CoroSplit.h
@@ -28,6 +28,7 @@ struct CoroSplitPass : PassInfoMixin<CoroSplitPass> {
LazyCallGraph &CG, CGSCCUpdateResult &UR);
static bool isRequired() { return true; }
+ // Would be true if the Optimization level isn't O0.
bool ReuseFrameSlot;
};
} // end namespace llvm
diff --git a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
index a6c6c4adb87f0..32620d09604af 100644
--- a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -1245,7 +1245,7 @@ static Instruction *insertSpills(const FrameDataInfo &FrameData,
&*Builder.GetInsertPoint());
// This dbg.declare is for the main function entry point. It
// will be deleted in all coro-split functions.
- coro::salvageDebugInfo(DbgPtrAllocaCache, DDI);
+ coro::salvageDebugInfo(DbgPtrAllocaCache, DDI, Shape.ReuseFrameSlot);
}
}
@@ -2144,7 +2144,7 @@ static void collectFrameAllocas(Function &F, coro::Shape &Shape,
void coro::salvageDebugInfo(
SmallDenseMap<llvm::Value *, llvm::AllocaInst *, 4> &DbgPtrAllocaCache,
- DbgDeclareInst *DDI) {
+ DbgDeclareInst *DDI, bool ReuseFrameSlot) {
Function *F = DDI->getFunction();
IRBuilder<> Builder(F->getContext());
auto InsertPt = F->getEntryBlock().getFirstInsertionPt();
@@ -2189,28 +2189,34 @@ void coro::salvageDebugInfo(
// is available throughout the function when producing unoptimized
// code. Extending the lifetime this way is correct because the
// variable has been declared by a dbg.declare intrinsic.
- if (auto Arg = dyn_cast_or_null<llvm::Argument>(Storage)) {
- auto &Cached = DbgPtrAllocaCache[Storage];
- if (!Cached) {
- Cached = Builder.CreateAlloca(Storage->getType(), 0, nullptr,
- Arg->getName() + ".debug");
- Builder.CreateStore(Storage, Cached);
+ //
+ // Avoid to create the alloca would be eliminated by optimization
+ // passes and the corresponding dbg.declares would be invalid.
+ if (!ReuseFrameSlot && !EnableReuseStorageInFrame)
+ if (auto *Arg = dyn_cast<llvm::Argument>(Storage)) {
+ auto &Cached = DbgPtrAllocaCache[Storage];
+ if (!Cached) {
+ Cached = Builder.CreateAlloca(Storage->getType(), 0, nullptr,
+ Arg->getName() + ".debug");
+ Builder.CreateStore(Storage, Cached);
+ }
+ Storage = Cached;
+ // FIXME: LLVM lacks nuanced semantics to
diff erentiate between
+ // memory and direct locations at the IR level. The backend will
+ // turn a dbg.declare(alloca, ..., DIExpression()) into a memory
+ // location. Thus, if there are deref and offset operations in the
+ // expression, we need to add a DW_OP_deref at the *start* of the
+ // expression to first load the contents of the alloca before
+ // adjusting it with the expression.
+ if (Expr && Expr->isComplex())
+ Expr = DIExpression::prepend(Expr, DIExpression::DerefBefore);
}
- Storage = Cached;
- // FIXME: LLVM lacks nuanced semantics to
diff erentiate between
- // memory and direct locations at the IR level. The backend will
- // turn a dbg.declare(alloca, ..., DIExpression()) into a memory
- // location. Thus, if there are deref and offset operations in the
- // expression, we need to add a DW_OP_deref at the *start* of the
- // expression to first load the contents of the alloca before
- // adjusting it with the expression.
- if (Expr && Expr->isComplex())
- Expr = DIExpression::prepend(Expr, DIExpression::DerefBefore);
- }
DDI->replaceVariableLocationOp(OriginalStorage, Storage);
DDI->setExpression(Expr);
- if (auto *InsertPt = dyn_cast_or_null<Instruction>(Storage))
+ if (auto *InsertPt = dyn_cast<Instruction>(Storage))
DDI->moveAfter(InsertPt);
+ else if (isa<Argument>(Storage))
+ DDI->moveAfter(F->getEntryBlock().getFirstNonPHI());
}
void coro::buildCoroutineFrame(Function &F, Shape &Shape) {
diff --git a/llvm/lib/Transforms/Coroutines/CoroInternal.h b/llvm/lib/Transforms/Coroutines/CoroInternal.h
index 8930c8593f3f1..eac8a83e427e2 100644
--- a/llvm/lib/Transforms/Coroutines/CoroInternal.h
+++ b/llvm/lib/Transforms/Coroutines/CoroInternal.h
@@ -54,7 +54,7 @@ void updateCallGraph(Function &Caller, ArrayRef<Function *> Funcs,
/// holding a pointer to the coroutine frame.
void salvageDebugInfo(
SmallDenseMap<llvm::Value *, llvm::AllocaInst *, 4> &DbgPtrAllocaCache,
- DbgDeclareInst *DDI);
+ DbgDeclareInst *DDI, bool ReuseFrameSlot);
// Keeps data and helper functions for lowering coroutine intrinsics.
struct LowererBase {
@@ -125,6 +125,7 @@ struct LLVM_LIBRARY_VISIBILITY Shape {
Instruction *FramePtr;
BasicBlock *AllocaSpillBlock;
+ /// This would only be true if optimization are enabled.
bool ReuseFrameSlot;
struct SwitchLoweringStorage {
diff --git a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
index 4c1a7167a1253..643b7f13b2449 100644
--- a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -654,7 +654,7 @@ void CoroCloner::salvageDebugInfo() {
if (auto *DDI = dyn_cast<DbgDeclareInst>(&I))
Worklist.push_back(DDI);
for (DbgDeclareInst *DDI : Worklist)
- coro::salvageDebugInfo(DbgPtrAllocaCache, DDI);
+ coro::salvageDebugInfo(DbgPtrAllocaCache, DDI, Shape.ReuseFrameSlot);
// Remove all salvaged dbg.declare intrinsics that became
// either unreachable or stale due to the CoroSplit transformation.
diff --git a/llvm/test/Transforms/Coroutines/coro-debug-O2.ll b/llvm/test/Transforms/Coroutines/coro-debug-O2.ll
new file mode 100644
index 0000000000000..0ab8cfe84ffa1
--- /dev/null
+++ b/llvm/test/Transforms/Coroutines/coro-debug-O2.ll
@@ -0,0 +1,172 @@
+; RUN: opt < %s -coro-early -coro-split -reuse-storage-in-coroutine-frame -coro-split -sroa -S | FileCheck %s
+
+; Checks whether the dbg.declare for `__promise` remains valid under O2.
+
+; CHECK-LABEL: define internal fastcc void @f.resume({{.*}})
+; CHECK: entry.resume:
+; CHECK: call void @llvm.dbg.declare(metadata %f.Frame* %FramePtr, metadata ![[PROMISEVAR_RESUME:[0-9]+]], metadata !DIExpression(
+;
+; CHECK: ![[PROMISEVAR_RESUME]] = !DILocalVariable(name: "__promise"
+%promise_type = type { i32, i32, double }
+
+define void @f() !dbg !8 {
+entry:
+ %__promise = alloca %promise_type, align 8
+ %0 = bitcast %promise_type* %__promise to i8*
+ %id = call token @llvm.coro.id(i32 16, i8* %0, i8* null, i8* null)
+ %alloc = call i1 @llvm.coro.alloc(token %id)
+ br i1 %alloc, label %coro.alloc, label %coro.init
+
+coro.alloc: ; preds = %entry
+ %size = call i64 @llvm.coro.size.i64()
+ %memory = call i8* @new(i64 %size)
+ br label %coro.init
+
+coro.init: ; preds = %coro.alloc, %entry
+ %phi.entry.alloc = phi i8* [ null, %entry ], [ %memory, %coro.alloc ]
+ %begin = call i8* @llvm.coro.begin(token %id, i8* %phi.entry.alloc)
+ call void @llvm.dbg.declare(metadata %promise_type* %__promise, metadata !6, metadata !DIExpression()), !dbg !18
+ %i.i = getelementptr inbounds %promise_type, %promise_type* %__promise, i64 0, i32 0
+ store i32 1, i32* %i.i, align 8
+ %j.i = getelementptr inbounds %promise_type, %promise_type* %__promise, i64 0, i32 1
+ store i32 2, i32* %j.i, align 4
+ %k.i = getelementptr inbounds %promise_type, %promise_type* %__promise, i64 0, i32 2
+ store double 3.000000e+00, double* %k.i, align 8
+ %ready = call i1 @await_ready()
+ br i1 %ready, label %init.ready, label %init.suspend
+
+init.suspend: ; preds = %coro.init
+ %save = call token @llvm.coro.save(i8* null)
+ call void @await_suspend()
+ %suspend = call i8 @llvm.coro.suspend(token %save, i1 false)
+ switch i8 %suspend, label %coro.ret [
+ i8 0, label %init.ready
+ i8 1, label %init.cleanup
+ ]
+
+init.cleanup: ; preds = %init.suspend
+ br label %cleanup
+
+init.ready: ; preds = %init.suspend, %coro.init
+ call void @await_resume()
+ %ready.again = call zeroext i1 @await_ready()
+ br i1 %ready.again, label %await.ready, label %await.suspend
+
+await.suspend: ; preds = %init.ready
+ %save.again = call token @llvm.coro.save(i8* null)
+ %from.address = call i8* @from_address(i8* %begin)
+ call void @await_suspend()
+ %suspend.again = call i8 @llvm.coro.suspend(token %save.again, i1 false)
+ switch i8 %suspend.again, label %coro.ret [
+ i8 0, label %await.ready
+ i8 1, label %await.cleanup
+ ]
+
+await.cleanup: ; preds = %await.suspend
+ br label %cleanup
+
+await.ready: ; preds = %await.suspend, %init.ready
+ call void @await_resume()
+ call void @return_void()
+ br label %coro.final
+
+coro.final: ; preds = %await.ready
+ call void @final_suspend()
+ %coro.final.await_ready = call i1 @await_ready()
+ br i1 %coro.final.await_ready, label %final.ready, label %final.suspend
+
+final.suspend: ; preds = %coro.final
+ %final.suspend.coro.save = call token @llvm.coro.save(i8* null)
+ %final.suspend.from_address = call i8* @from_address(i8* %begin)
+ call void @await_suspend()
+ %final.suspend.coro.suspend = call i8 @llvm.coro.suspend(token %final.suspend.coro.save, i1 true)
+ switch i8 %final.suspend.coro.suspend, label %coro.ret [
+ i8 0, label %final.ready
+ i8 1, label %final.cleanup
+ ]
+
+final.cleanup: ; preds = %final.suspend
+ br label %cleanup
+
+final.ready: ; preds = %final.suspend, %coro.final
+ call void @await_resume()
+ br label %cleanup
+
+cleanup: ; preds = %final.ready, %final.cleanup, %await.cleanup, %init.cleanup
+ %cleanup.dest.slot.0 = phi i32 [ 0, %final.ready ], [ 2, %final.cleanup ], [ 2, %await.cleanup ], [ 2, %init.cleanup ]
+ %free.memory = call i8* @llvm.coro.free(token %id, i8* %begin)
+ %free = icmp ne i8* %free.memory, null
+ br i1 %free, label %coro.free, label %after.coro.free
+
+coro.free: ; preds = %cleanup
+ call void @delete(i8* %free.memory)
+ br label %after.coro.free
+
+after.coro.free: ; preds = %coro.free, %cleanup
+ switch i32 %cleanup.dest.slot.0, label %unreachable [
+ i32 0, label %cleanup.cont
+ i32 2, label %coro.ret
+ ]
+
+cleanup.cont: ; preds = %after.coro.free
+ br label %coro.ret
+
+coro.ret: ; preds = %cleanup.cont, %after.coro.free, %final.suspend, %await.suspend, %init.suspend
+ %end = call i1 @llvm.coro.end(i8* null, i1 false)
+ ret void
+
+unreachable: ; preds = %after.coro.free
+ unreachable
+
+}
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+declare token @llvm.coro.id(i32, i8* readnone, i8* nocapture readonly, i8*)
+declare i1 @llvm.coro.alloc(token)
+declare i64 @llvm.coro.size.i64()
+declare token @llvm.coro.save(i8*)
+declare i8* @llvm.coro.begin(token, i8* writeonly)
+declare i8 @llvm.coro.suspend(token, i1)
+declare i8* @llvm.coro.free(token, i8* nocapture readonly)
+declare i1 @llvm.coro.end(i8*, i1)
+
+declare i8* @new(i64)
+declare void @delete(i8*)
+declare i1 @await_ready()
+declare void @await_suspend()
+declare void @await_resume()
+declare void @print(i32)
+declare i8* @from_address(i8*)
+declare void @return_void()
+declare void @final_suspend()
+
+!llvm.dbg.cu = !{!0}
+!llvm.linker.options = !{}
+!llvm.module.flags = !{!3, !4}
+!llvm.ident = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 11.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !2, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "coro-debug.cpp", directory: ".")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{!"clang version 11.0.0"}
+!6 = !DILocalVariable(name: "__promise", scope: !7, file: !1, line: 24, type: !10)
+!7 = distinct !DILexicalBlock(scope: !8, file: !1, line: 23, column: 12)
+!8 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !8, file: !1, line: 23, type: !9, scopeLine: 23, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!9 = !DISubroutineType(types: !2)
+!10 = !DIDerivedType(tag: DW_TAG_typedef, name: "promise_type", scope: !8, file: !1, line: 15, baseType: !11)
+!11 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "promise_type", scope: !8, file: !1, line: 10, size: 128, flags: DIFlagTypePassByValue | DIFlagNonTrivial, elements: !12, identifier: "_ZTSN4coro12promise_typeE")
+!12 = !{!13, !14, !15}
+!13 = !DIDerivedType(tag: DW_TAG_member, name: "i", scope: !8, file: !1, line: 10, baseType: !16, size: 32)
+!14 = !DIDerivedType(tag: DW_TAG_member, name: "j", scope: !8, file: !1, line: 10, baseType: !16, size: 32, offset: 32)
+!15 = !DIDerivedType(tag: DW_TAG_member, name: "k", scope: !8, file: !1, line: 10, baseType: !17, size: 64, offset: 64)
+!16 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!17 = !DIBasicType(name: "double", size: 64, encoding: DW_ATE_float)
+!18 = !DILocation(line: 0, scope: !7)
+
+
+
+
+
+
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