r317981 - [coroutines] Promote cleanup.dest.slot allocas to registers to avoid storing it in the coroutine frame
Gor Nishanov via cfe-commits
cfe-commits at lists.llvm.org
Sat Nov 11 09:00:43 PST 2017
Author: gornishanov
Date: Sat Nov 11 09:00:43 2017
New Revision: 317981
URL: http://llvm.org/viewvc/llvm-project?rev=317981&view=rev
Log:
[coroutines] Promote cleanup.dest.slot allocas to registers to avoid storing it in the coroutine frame
Summary:
We don't want to store cleanup dest slot saved into the coroutine frame (as some of the cleanup code may
access them after coroutine frame destroyed).
This is an alternative to https://reviews.llvm.org/D37093
It is possible to do this for all functions, but, cursory check showed that in -O0, we get slightly longer function (by 1-3 instructions), thus, we are only limiting cleanup.dest.slot elimination to coroutines.
Reviewers: rjmccall, hfinkel, eric_niebler
Reviewed By: eric_niebler
Subscribers: EricWF, cfe-commits
Differential Revision: https://reviews.llvm.org/D39768
Added:
cfe/trunk/test/CodeGenCoroutines/coro-dest-slot.cpp
Modified:
cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
cfe/trunk/lib/CodeGen/CodeGenFunction.h
Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.cpp?rev=317981&r1=317980&r2=317981&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.cpp (original)
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.cpp Sat Nov 11 09:00:43 2017
@@ -33,9 +33,11 @@
#include "clang/Frontend/CodeGenOptions.h"
#include "clang/Sema/SemaDiagnostic.h"
#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Operator.h"
+#include "llvm/Transforms/Utils/PromoteMemToReg.h"
using namespace clang;
using namespace CodeGen;
@@ -419,6 +421,18 @@ void CodeGenFunction::FinishFunction(Sou
I->first->replaceAllUsesWith(I->second);
I->first->eraseFromParent();
}
+
+ // Eliminate CleanupDestSlot alloca by replacing it with SSA values and
+ // PHIs if the current function is a coroutine. We don't do it for all
+ // functions as it may result in slight increase in numbers of instructions
+ // if compiled with no optimizations. We do it for coroutine as the lifetime
+ // of CleanupDestSlot alloca make correct coroutine frame building very
+ // difficult.
+ if (NormalCleanupDest && isCoroutine()) {
+ llvm::DominatorTree DT(*CurFn);
+ llvm::PromoteMemToReg(NormalCleanupDest, DT);
+ NormalCleanupDest = nullptr;
+ }
}
/// ShouldInstrumentFunction - Return true if the current function should be
Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=317981&r1=317980&r2=317981&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Sat Nov 11 09:00:43 2017
@@ -225,6 +225,10 @@ public:
};
CGCoroInfo CurCoro;
+ bool isCoroutine() const {
+ return CurCoro.Data != nullptr;
+ }
+
/// CurGD - The GlobalDecl for the current function being compiled.
GlobalDecl CurGD;
@@ -764,7 +768,7 @@ public:
ForceCleanup();
}
- /// Checks if the global variable is captured in current function.
+ /// Checks if the global variable is captured in current function.
bool isGlobalVarCaptured(const VarDecl *VD) const {
VD = VD->getCanonicalDecl();
return !VD->isLocalVarDeclOrParm() && CGF.LocalDeclMap.count(VD) > 0;
@@ -826,7 +830,7 @@ public:
/// block through the normal cleanup handling code (if any) and then
/// on to \arg Dest.
void EmitBranchThroughCleanup(JumpDest Dest);
-
+
/// isObviouslyBranchWithoutCleanups - Return true if a branch to the
/// specified destination obviously has no cleanups to run. 'false' is always
/// a conservatively correct answer for this method.
@@ -1045,7 +1049,7 @@ public:
if (Data.isValid()) Data.unbind(CGF);
}
};
-
+
private:
CGDebugInfo *DebugInfo;
bool DisableDebugInfo;
@@ -1434,7 +1438,7 @@ private:
/// Add OpenCL kernel arg metadata and the kernel attribute meatadata to
/// the function metadata.
- void EmitOpenCLKernelMetadata(const FunctionDecl *FD,
+ void EmitOpenCLKernelMetadata(const FunctionDecl *FD,
llvm::Function *Fn);
public:
@@ -1443,10 +1447,10 @@ public:
CodeGenTypes &getTypes() const { return CGM.getTypes(); }
ASTContext &getContext() const { return CGM.getContext(); }
- CGDebugInfo *getDebugInfo() {
- if (DisableDebugInfo)
+ CGDebugInfo *getDebugInfo() {
+ if (DisableDebugInfo)
return nullptr;
- return DebugInfo;
+ return DebugInfo;
}
void disableDebugInfo() { DisableDebugInfo = true; }
void enableDebugInfo() { DisableDebugInfo = false; }
@@ -2509,7 +2513,7 @@ public:
};
AutoVarEmission EmitAutoVarAlloca(const VarDecl &var);
void EmitAutoVarInit(const AutoVarEmission &emission);
- void EmitAutoVarCleanups(const AutoVarEmission &emission);
+ void EmitAutoVarCleanups(const AutoVarEmission &emission);
void emitAutoVarTypeCleanup(const AutoVarEmission &emission,
QualType::DestructionKind dtorKind);
@@ -2531,7 +2535,7 @@ public:
bool isIndirect() const { return Alignment != 0; }
llvm::Value *getAnyValue() const { return Value; }
-
+
llvm::Value *getDirectValue() const {
assert(!isIndirect());
return Value;
@@ -3188,7 +3192,7 @@ public:
LValue EmitCastLValue(const CastExpr *E);
LValue EmitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
LValue EmitOpaqueValueLValue(const OpaqueValueExpr *e);
-
+
Address EmitExtVectorElementLValue(LValue V);
RValue EmitRValueForField(LValue LV, const FieldDecl *FD, SourceLocation Loc);
@@ -3305,12 +3309,12 @@ public:
void EmitNoreturnRuntimeCallOrInvoke(llvm::Value *callee,
ArrayRef<llvm::Value*> args);
- CGCallee BuildAppleKextVirtualCall(const CXXMethodDecl *MD,
+ CGCallee BuildAppleKextVirtualCall(const CXXMethodDecl *MD,
NestedNameSpecifier *Qual,
llvm::Type *Ty);
-
+
CGCallee BuildAppleKextVirtualDestructorCall(const CXXDestructorDecl *DD,
- CXXDtorType Type,
+ CXXDtorType Type,
const CXXRecordDecl *RD);
RValue
@@ -3484,11 +3488,11 @@ public:
static Destroyer destroyARCWeak;
static Destroyer emitARCIntrinsicUse;
- void EmitObjCAutoreleasePoolPop(llvm::Value *Ptr);
+ void EmitObjCAutoreleasePoolPop(llvm::Value *Ptr);
llvm::Value *EmitObjCAutoreleasePoolPush();
llvm::Value *EmitObjCMRRAutoreleasePoolPush();
void EmitObjCAutoreleasePoolCleanup(llvm::Value *Ptr);
- void EmitObjCMRRAutoreleasePoolPop(llvm::Value *Ptr);
+ void EmitObjCMRRAutoreleasePoolPop(llvm::Value *Ptr);
/// \brief Emits a reference binding to the passed in expression.
RValue EmitReferenceBindingToExpr(const Expr *E);
@@ -3603,7 +3607,7 @@ public:
bool PerformInit);
void EmitCXXConstructExpr(const CXXConstructExpr *E, AggValueSlot Dest);
-
+
void EmitSynthesizedCXXCopyCtor(Address Dest, Address Src, const Expr *Exp);
void enterFullExpression(const ExprWithCleanups *E) {
@@ -3652,7 +3656,7 @@ public:
/// Determine if the given statement might introduce a declaration into the
/// current scope, by being a (possibly-labelled) DeclStmt.
static bool mightAddDeclToScope(const Stmt *S);
-
+
/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
/// to a constant, or if it does but contains a label, return false. If it
/// constant folds return true and set the boolean result in Result.
Added: cfe/trunk/test/CodeGenCoroutines/coro-dest-slot.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCoroutines/coro-dest-slot.cpp?rev=317981&view=auto
==============================================================================
--- cfe/trunk/test/CodeGenCoroutines/coro-dest-slot.cpp (added)
+++ cfe/trunk/test/CodeGenCoroutines/coro-dest-slot.cpp Sat Nov 11 09:00:43 2017
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fcoroutines-ts -std=c++14 -emit-llvm %s -o - -disable-llvm-passes | FileCheck %s
+
+#include "Inputs/coroutine.h"
+
+using namespace std::experimental;
+
+struct coro {
+ struct promise_type {
+ coro get_return_object();
+ suspend_always initial_suspend();
+ suspend_never final_suspend();
+ void return_void();
+ static void unhandled_exception();
+ };
+};
+
+extern "C" coro f(int) { co_return; }
+// Verify that cleanup.dest.slot is eliminated in a coroutine.
+// CHECK-LABEL: f(
+// CHECK: call void @_ZNSt12experimental13coroutines_v113suspend_never12await_resumeEv(
+// CHECK: %[[CLEANUP_DEST:.+]] = phi i32 [ 0, %{{.+}} ], [ 2, %{{.+}} ], [ 2, %{{.+}} ]
+// CHECK: call i8* @llvm.coro.free(
+// CHECK: switch i32 %cleanup.dest.slot.0, label %{{.+}} [
+// CHECK-NEXT: i32 0
+// CHECK-NEXT: i32 2
+// CHECK-NEXT: ]
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