From db38485588fdba5b02225c7973c4cc1c74edf544 Mon Sep 17 00:00:00 2001 From: Gor Nishanov Date: Wed, 17 May 2017 03:09:22 +0000 Subject: [PATCH] [coroutines] Handle spills before catchswitch If we need to spill the result of the PHI instruction, we insert the spill after all of the PHIs and EHPads, however, in a catchswitch block there is no room to insert the spill. Make room by splitting away catchswitch into a separate block. Before the fix: catch.dispatch: %val = phi i32 [ 1, %if.then ], [ 2, %if.else ] %switch = catchswitch within none [label %catch] unwind label %cleanuppad After: catch.dispatch: %val = phi i32 [ 1, %if.then ], [ 2, %if.else ] %tok = cleanuppad within none [] ; spill goes here cleanupret from %tok unwind label %catch.dispatch.switch catch.dispatch.switch: %switch = catchswitch within none [label %catch] unwind label %cleanuppad https://reviews.llvm.org/D31846 llvm-svn: 303232 --- llvm/lib/Transforms/Coroutines/CoroFrame.cpp | 28 ++++++- .../test/Transforms/Coroutines/coro-catchswitch.ll | 88 ++++++++++++++++++++++ 2 files changed, 114 insertions(+), 2 deletions(-) create mode 100644 llvm/test/Transforms/Coroutines/coro-catchswitch.ll diff --git a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp index 4480220..417d57f 100644 --- a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp +++ b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp @@ -347,6 +347,27 @@ static StructType *buildFrameType(Function &F, coro::Shape &Shape, return FrameTy; } +// We need to make room to insert a spill after initial PHIs, but before +// catchswitch instruction. Placing it before violates the requirement that +// catchswitch, like all other EHPads must be the first nonPHI in a block. +// +// Split away catchswitch into a separate block and insert in its place: +// +// cleanuppad cleanupret. +// +// cleanupret instruction will act as an insert point for the spill. +static Instruction *splitBeforeCatchSwitch(CatchSwitchInst *CatchSwitch) { + BasicBlock *CurrentBlock = CatchSwitch->getParent(); + BasicBlock *NewBlock = CurrentBlock->splitBasicBlock(CatchSwitch); + CurrentBlock->getTerminator()->eraseFromParent(); + + auto *CleanupPad = + CleanupPadInst::Create(CatchSwitch->getParentPad(), {}, "", CurrentBlock); + auto *CleanupRet = + CleanupReturnInst::Create(CleanupPad, NewBlock, CurrentBlock); + return CleanupRet; +} + // Replace all alloca and SSA values that are accessed across suspend points // with GetElementPointer from coroutine frame + loads and stores. Create an // AllocaSpillBB that will become the new entry block for the resume parts of @@ -437,8 +458,11 @@ static Instruction *insertSpills(SpillInfo &Spills, coro::Shape &Shape) { InsertPt = NewBB->getTerminator(); } else if (dyn_cast(CurrentValue)) { // Skip the PHINodes and EH pads instructions. - InsertPt = - &*cast(E.def())->getParent()->getFirstInsertionPt(); + BasicBlock *DefBlock = cast(E.def())->getParent(); + if (auto *CSI = dyn_cast(DefBlock->getTerminator())) + InsertPt = splitBeforeCatchSwitch(CSI); + else + InsertPt = &*DefBlock->getFirstInsertionPt(); } else { // For all other values, the spill is placed immediately after // the definition. diff --git a/llvm/test/Transforms/Coroutines/coro-catchswitch.ll b/llvm/test/Transforms/Coroutines/coro-catchswitch.ll new file mode 100644 index 0000000..dd06f12 --- /dev/null +++ b/llvm/test/Transforms/Coroutines/coro-catchswitch.ll @@ -0,0 +1,88 @@ +; Verifies that we can insert the spill for a PHI preceding the catchswitch +; RUN: opt < %s -coro-split -S | FileCheck %s + +target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32" +target triple = "i686-pc-windows-msvc" + +; CHECK-LABEL: define void @f( +define void @f(i1 %cond) "coroutine.presplit"="1" personality i32 0 { +entry: + %id = call token @llvm.coro.id(i32 8, i8* null, i8* null, i8* null) + %size = call i32 @llvm.coro.size.i32() + %alloc = call i8* @malloc(i32 %size) + %hdl = call i8* @llvm.coro.begin(token %id, i8* %alloc) + br i1 %cond, label %if.else, label %if.then + +if.then: + invoke void @may_throw1() + to label %coro.ret unwind label %catch.dispatch + +if.else: + invoke void @may_throw2() + to label %coro.ret unwind label %catch.dispatch + +catch.dispatch: ; preds = %if.else, %if.then + %val = phi i32 [ 1, %if.then ], [ 2, %if.else ] + %switch = catchswitch within none [label %catch] unwind label %cleanuppad + +; Verifies that we split out the PHI into a separate block +; added a cleanuppad spill cleanupret unwinding into the catchswitch. + +; CHECK: catch.dispatch: +; CHECK: %val = phi i32 [ 2, %if.else ], [ 1, %if.then ] +; CHECK: %[[Pad:.+]] = cleanuppad within none [] +; CHECK: %val.spill.addr = getelementptr inbounds %f.Frame, %f.Frame* %FramePtr, i32 0, i32 4 +; CHECK: store i32 %val, i32* %val.spill.addr +; CHECK: cleanupret from %[[Pad]] unwind label %[[Switch:.+]] + +; CHECK: [[Switch]]: +; CHECK: %switch = catchswitch within none [label %catch] unwind to caller + +catch: ; preds = %catch.dispatch + %pad = catchpad within %switch [i8* null, i32 64, i8* null] + catchret from %pad to label %suspend + +suspend: + %sp = call i8 @llvm.coro.suspend(token none, i1 false) + switch i8 %sp, label %coro.ret [ + i8 0, label %resume + i8 1, label %coro.ret + ] + +resume: ; preds = %await2.suspend + call void @print(i32 %val) + br label %coro.ret + +coro.ret: + call i1 @llvm.coro.end(i8* %hdl, i1 0) + ret void + +cleanuppad: + %cpad = cleanuppad within none [] + cleanupret from %cpad unwind to caller +} + +; Function Attrs: argmemonly nounwind readonly +declare token @llvm.coro.id(i32, i8* readnone, i8* nocapture readonly, i8*) #1 + +; Function Attrs: nounwind +declare i1 @llvm.coro.alloc(token) #2 + +; Function Attrs: nobuiltin +declare i32 @llvm.coro.size.i32() #4 +declare i8* @llvm.coro.begin(token, i8* writeonly) #2 +declare token @llvm.coro.save(i8*) +declare i8 @llvm.coro.suspend(token, i1) + +declare void @may_throw1() +declare void @may_throw2() +declare void @print(i32) +declare noalias i8* @malloc(i32) +declare void @free(i8*) + +declare i1 @llvm.coro.end(i8*, i1) #2 + +; Function Attrs: nobuiltin nounwind + +; Function Attrs: argmemonly nounwind readonly +declare i8* @llvm.coro.free(token, i8* nocapture readonly) #1 -- 2.7.4