forked from OSchip/llvm-project
[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
This commit is contained in:
Chuanqi Xu
parent
d332bbee45
commit
eb51dd719f
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@ -23,7 +23,7 @@ void addCoroutinePassesToExtensionPoints(PassManagerBuilder &Builder);
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Pass *createCoroEarlyLegacyPass();
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/// Split up coroutines into multiple functions driving their state machines.
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Pass *createCoroSplitLegacyPass(bool ReuseFrameSlot = false);
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Pass *createCoroSplitLegacyPass(bool IsOptimizing = false);
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/// Analyze coroutines use sites, devirtualize resume/destroy calls and elide
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/// heap allocation for coroutine frame where possible.
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@ -28,6 +28,7 @@ struct CoroSplitPass : PassInfoMixin<CoroSplitPass> {
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LazyCallGraph &CG, CGSCCUpdateResult &UR);
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static bool isRequired() { return true; }
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// Would be true if the Optimization level isn't O0.
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bool ReuseFrameSlot;
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};
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} // end namespace llvm
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@ -1245,7 +1245,7 @@ static Instruction *insertSpills(const FrameDataInfo &FrameData,
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&*Builder.GetInsertPoint());
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// This dbg.declare is for the main function entry point. It
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// will be deleted in all coro-split functions.
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coro::salvageDebugInfo(DbgPtrAllocaCache, DDI);
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coro::salvageDebugInfo(DbgPtrAllocaCache, DDI, Shape.ReuseFrameSlot);
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}
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}
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@ -2144,7 +2144,7 @@ static void collectFrameAllocas(Function &F, coro::Shape &Shape,
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void coro::salvageDebugInfo(
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SmallDenseMap<llvm::Value *, llvm::AllocaInst *, 4> &DbgPtrAllocaCache,
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DbgDeclareInst *DDI) {
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DbgDeclareInst *DDI, bool ReuseFrameSlot) {
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Function *F = DDI->getFunction();
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IRBuilder<> Builder(F->getContext());
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auto InsertPt = F->getEntryBlock().getFirstInsertionPt();
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@ -2189,28 +2189,34 @@ void coro::salvageDebugInfo(
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// is available throughout the function when producing unoptimized
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// code. Extending the lifetime this way is correct because the
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// variable has been declared by a dbg.declare intrinsic.
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if (auto Arg = dyn_cast_or_null<llvm::Argument>(Storage)) {
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auto &Cached = DbgPtrAllocaCache[Storage];
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if (!Cached) {
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Cached = Builder.CreateAlloca(Storage->getType(), 0, nullptr,
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Arg->getName() + ".debug");
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Builder.CreateStore(Storage, Cached);
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//
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// Avoid to create the alloca would be eliminated by optimization
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// passes and the corresponding dbg.declares would be invalid.
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if (!ReuseFrameSlot && !EnableReuseStorageInFrame)
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if (auto *Arg = dyn_cast<llvm::Argument>(Storage)) {
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auto &Cached = DbgPtrAllocaCache[Storage];
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if (!Cached) {
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Cached = Builder.CreateAlloca(Storage->getType(), 0, nullptr,
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Arg->getName() + ".debug");
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Builder.CreateStore(Storage, Cached);
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}
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Storage = Cached;
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// FIXME: LLVM lacks nuanced semantics to differentiate between
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// memory and direct locations at the IR level. The backend will
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// turn a dbg.declare(alloca, ..., DIExpression()) into a memory
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// location. Thus, if there are deref and offset operations in the
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// expression, we need to add a DW_OP_deref at the *start* of the
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// expression to first load the contents of the alloca before
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// adjusting it with the expression.
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if (Expr && Expr->isComplex())
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Expr = DIExpression::prepend(Expr, DIExpression::DerefBefore);
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}
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Storage = Cached;
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// FIXME: LLVM lacks nuanced semantics to differentiate between
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// memory and direct locations at the IR level. The backend will
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// turn a dbg.declare(alloca, ..., DIExpression()) into a memory
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// location. Thus, if there are deref and offset operations in the
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// expression, we need to add a DW_OP_deref at the *start* of the
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// expression to first load the contents of the alloca before
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// adjusting it with the expression.
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if (Expr && Expr->isComplex())
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Expr = DIExpression::prepend(Expr, DIExpression::DerefBefore);
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}
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DDI->replaceVariableLocationOp(OriginalStorage, Storage);
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DDI->setExpression(Expr);
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if (auto *InsertPt = dyn_cast_or_null<Instruction>(Storage))
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if (auto *InsertPt = dyn_cast<Instruction>(Storage))
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DDI->moveAfter(InsertPt);
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else if (isa<Argument>(Storage))
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DDI->moveAfter(F->getEntryBlock().getFirstNonPHI());
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}
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void coro::buildCoroutineFrame(Function &F, Shape &Shape) {
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@ -54,7 +54,7 @@ void updateCallGraph(Function &Caller, ArrayRef<Function *> Funcs,
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/// holding a pointer to the coroutine frame.
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void salvageDebugInfo(
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SmallDenseMap<llvm::Value *, llvm::AllocaInst *, 4> &DbgPtrAllocaCache,
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DbgDeclareInst *DDI);
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DbgDeclareInst *DDI, bool ReuseFrameSlot);
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// Keeps data and helper functions for lowering coroutine intrinsics.
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struct LowererBase {
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@ -125,6 +125,7 @@ struct LLVM_LIBRARY_VISIBILITY Shape {
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Instruction *FramePtr;
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BasicBlock *AllocaSpillBlock;
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/// This would only be true if optimization are enabled.
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bool ReuseFrameSlot;
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struct SwitchLoweringStorage {
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@ -654,7 +654,7 @@ void CoroCloner::salvageDebugInfo() {
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if (auto *DDI = dyn_cast<DbgDeclareInst>(&I))
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Worklist.push_back(DDI);
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for (DbgDeclareInst *DDI : Worklist)
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coro::salvageDebugInfo(DbgPtrAllocaCache, DDI);
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coro::salvageDebugInfo(DbgPtrAllocaCache, DDI, Shape.ReuseFrameSlot);
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// Remove all salvaged dbg.declare intrinsics that became
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// either unreachable or stale due to the CoroSplit transformation.
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@ -0,0 +1,172 @@
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; RUN: opt < %s -coro-early -coro-split -reuse-storage-in-coroutine-frame -coro-split -sroa -S | FileCheck %s
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; Checks whether the dbg.declare for `__promise` remains valid under O2.
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; CHECK-LABEL: define internal fastcc void @f.resume({{.*}})
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; CHECK: entry.resume:
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; CHECK: call void @llvm.dbg.declare(metadata %f.Frame* %FramePtr, metadata ![[PROMISEVAR_RESUME:[0-9]+]], metadata !DIExpression(
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;
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; CHECK: ![[PROMISEVAR_RESUME]] = !DILocalVariable(name: "__promise"
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%promise_type = type { i32, i32, double }
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define void @f() !dbg !8 {
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entry:
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%__promise = alloca %promise_type, align 8
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%0 = bitcast %promise_type* %__promise to i8*
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%id = call token @llvm.coro.id(i32 16, i8* %0, i8* null, i8* null)
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%alloc = call i1 @llvm.coro.alloc(token %id)
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br i1 %alloc, label %coro.alloc, label %coro.init
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coro.alloc: ; preds = %entry
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%size = call i64 @llvm.coro.size.i64()
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%memory = call i8* @new(i64 %size)
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br label %coro.init
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coro.init: ; preds = %coro.alloc, %entry
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%phi.entry.alloc = phi i8* [ null, %entry ], [ %memory, %coro.alloc ]
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%begin = call i8* @llvm.coro.begin(token %id, i8* %phi.entry.alloc)
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call void @llvm.dbg.declare(metadata %promise_type* %__promise, metadata !6, metadata !DIExpression()), !dbg !18
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%i.i = getelementptr inbounds %promise_type, %promise_type* %__promise, i64 0, i32 0
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store i32 1, i32* %i.i, align 8
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%j.i = getelementptr inbounds %promise_type, %promise_type* %__promise, i64 0, i32 1
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store i32 2, i32* %j.i, align 4
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%k.i = getelementptr inbounds %promise_type, %promise_type* %__promise, i64 0, i32 2
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store double 3.000000e+00, double* %k.i, align 8
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%ready = call i1 @await_ready()
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br i1 %ready, label %init.ready, label %init.suspend
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init.suspend: ; preds = %coro.init
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%save = call token @llvm.coro.save(i8* null)
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call void @await_suspend()
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%suspend = call i8 @llvm.coro.suspend(token %save, i1 false)
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switch i8 %suspend, label %coro.ret [
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i8 0, label %init.ready
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i8 1, label %init.cleanup
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]
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init.cleanup: ; preds = %init.suspend
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br label %cleanup
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init.ready: ; preds = %init.suspend, %coro.init
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call void @await_resume()
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%ready.again = call zeroext i1 @await_ready()
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br i1 %ready.again, label %await.ready, label %await.suspend
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await.suspend: ; preds = %init.ready
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%save.again = call token @llvm.coro.save(i8* null)
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%from.address = call i8* @from_address(i8* %begin)
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call void @await_suspend()
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%suspend.again = call i8 @llvm.coro.suspend(token %save.again, i1 false)
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switch i8 %suspend.again, label %coro.ret [
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i8 0, label %await.ready
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i8 1, label %await.cleanup
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]
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await.cleanup: ; preds = %await.suspend
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br label %cleanup
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await.ready: ; preds = %await.suspend, %init.ready
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call void @await_resume()
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call void @return_void()
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br label %coro.final
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coro.final: ; preds = %await.ready
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call void @final_suspend()
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%coro.final.await_ready = call i1 @await_ready()
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br i1 %coro.final.await_ready, label %final.ready, label %final.suspend
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final.suspend: ; preds = %coro.final
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%final.suspend.coro.save = call token @llvm.coro.save(i8* null)
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%final.suspend.from_address = call i8* @from_address(i8* %begin)
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call void @await_suspend()
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%final.suspend.coro.suspend = call i8 @llvm.coro.suspend(token %final.suspend.coro.save, i1 true)
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switch i8 %final.suspend.coro.suspend, label %coro.ret [
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i8 0, label %final.ready
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i8 1, label %final.cleanup
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]
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final.cleanup: ; preds = %final.suspend
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br label %cleanup
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final.ready: ; preds = %final.suspend, %coro.final
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call void @await_resume()
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br label %cleanup
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cleanup: ; preds = %final.ready, %final.cleanup, %await.cleanup, %init.cleanup
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%cleanup.dest.slot.0 = phi i32 [ 0, %final.ready ], [ 2, %final.cleanup ], [ 2, %await.cleanup ], [ 2, %init.cleanup ]
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%free.memory = call i8* @llvm.coro.free(token %id, i8* %begin)
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%free = icmp ne i8* %free.memory, null
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br i1 %free, label %coro.free, label %after.coro.free
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coro.free: ; preds = %cleanup
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call void @delete(i8* %free.memory)
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br label %after.coro.free
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after.coro.free: ; preds = %coro.free, %cleanup
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switch i32 %cleanup.dest.slot.0, label %unreachable [
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i32 0, label %cleanup.cont
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i32 2, label %coro.ret
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]
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cleanup.cont: ; preds = %after.coro.free
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br label %coro.ret
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coro.ret: ; preds = %cleanup.cont, %after.coro.free, %final.suspend, %await.suspend, %init.suspend
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%end = call i1 @llvm.coro.end(i8* null, i1 false)
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ret void
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unreachable: ; preds = %after.coro.free
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unreachable
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}
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declare void @llvm.dbg.declare(metadata, metadata, metadata)
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declare token @llvm.coro.id(i32, i8* readnone, i8* nocapture readonly, i8*)
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declare i1 @llvm.coro.alloc(token)
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declare i64 @llvm.coro.size.i64()
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declare token @llvm.coro.save(i8*)
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declare i8* @llvm.coro.begin(token, i8* writeonly)
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declare i8 @llvm.coro.suspend(token, i1)
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declare i8* @llvm.coro.free(token, i8* nocapture readonly)
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declare i1 @llvm.coro.end(i8*, i1)
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declare i8* @new(i64)
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declare void @delete(i8*)
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declare i1 @await_ready()
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declare void @await_suspend()
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declare void @await_resume()
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declare void @print(i32)
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declare i8* @from_address(i8*)
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declare void @return_void()
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declare void @final_suspend()
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!llvm.dbg.cu = !{!0}
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!llvm.linker.options = !{}
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!llvm.module.flags = !{!3, !4}
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!llvm.ident = !{!5}
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!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)
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!1 = !DIFile(filename: "coro-debug.cpp", directory: ".")
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!2 = !{}
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!3 = !{i32 7, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{!"clang version 11.0.0"}
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!6 = !DILocalVariable(name: "__promise", scope: !7, file: !1, line: 24, type: !10)
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!7 = distinct !DILexicalBlock(scope: !8, file: !1, line: 23, column: 12)
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!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)
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!9 = !DISubroutineType(types: !2)
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!10 = !DIDerivedType(tag: DW_TAG_typedef, name: "promise_type", scope: !8, file: !1, line: 15, baseType: !11)
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!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")
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!12 = !{!13, !14, !15}
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!13 = !DIDerivedType(tag: DW_TAG_member, name: "i", scope: !8, file: !1, line: 10, baseType: !16, size: 32)
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!14 = !DIDerivedType(tag: DW_TAG_member, name: "j", scope: !8, file: !1, line: 10, baseType: !16, size: 32, offset: 32)
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!15 = !DIDerivedType(tag: DW_TAG_member, name: "k", scope: !8, file: !1, line: 10, baseType: !17, size: 64, offset: 64)
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!16 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!17 = !DIBasicType(name: "double", size: 64, encoding: DW_ATE_float)
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!18 = !DILocation(line: 0, scope: !7)
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