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Add "first class" lowering for deopt operand bundles

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Summary:
After this change, deopt operand bundles can be lowered directly by
SelectionDAG into STATEPOINT instructions (which are then lowered to a
call or sequence of nop, with an associated __llvm_stackmaps entry0.
This obviates the need to round-trip deoptimization state through
gc.statepoint via RewriteStatepointsForGC.

Reviewers: reames, atrick, majnemer, JosephTremoulet, pgavlin

Subscribers: sanjoy, mcrosier, majnemer, llvm-commits

Differential Revision: http://reviews.llvm.org/D18257

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264015 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Sanjoy Das 2016-03-22 00:59:13 +00:00
parent 668a12461d
commit 1ceb821951
6 changed files with 204 additions and 24 deletions
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1
include/llvm/IR/Statepoint.h
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@ -411,6 +411,7 @@ struct StatepointDirectives {
Optional<uint64_t> StatepointID;
static const uint64_t DefaultStatepointID = 0xABCDEF00;
static const uint64_t DeoptBundleStatepointID = 0xABCDEF0F;
};
/// Parse out statepoint directives from the function attributes present in \p

6
lib/CodeGen/SelectionDAG/FastISel.cpp
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@ -1351,6 +1351,12 @@ bool FastISel::selectInstruction(const Instruction *I) {
return false;
}
// FastISel does not handle any operand bundles except OB_funclet.
if (ImmutableCallSite CS = ImmutableCallSite(I))
for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i)
if (CS.getOperandBundleAt(i).getTagID() != LLVMContext::OB_funclet)
return false;
DbgLoc = I->getDebugLoc();
SavedInsertPt = FuncInfo.InsertPt;

37
lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
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@ -2127,6 +2127,15 @@ void SelectionDAGBuilder::visitInvoke(const InvokeInst &I) {
MachineBasicBlock *Return = FuncInfo.MBBMap[I.getSuccessor(0)];
const BasicBlock *EHPadBB = I.getSuccessor(1);
#ifndef NDEBUG
// Deopt bundles are lowered in LowerCallSiteWithDeoptBundle, and we don't
// have to do anything here to lower funclet bundles.
for (unsigned i = 0, e = I.getNumOperandBundles(); i != e; ++i)
assert((I.getOperandBundleAt(i).isDeoptOperandBundle() ||
I.getOperandBundleAt(i).isFuncletOperandBundle()) &&
"Cannot lower invokes with arbitrary operand bundles yet!");
#endif
const Value *Callee(I.getCalledValue());
const Function *Fn = dyn_cast<Function>(Callee);
if (isa<InlineAsm>(Callee))
@ -2146,8 +2155,15 @@ void SelectionDAGBuilder::visitInvoke(const InvokeInst &I) {
LowerStatepoint(ImmutableStatepoint(&I), EHPadBB);
break;
}
} else
} else if (I.countOperandBundlesOfType(LLVMContext::OB_deopt)) {
// Currently we do not lower any intrinsic calls with deopt operand bundles.
// Eventually we will support lowering the @llvm.experimental.deoptimize
// intrinsic, and right now there are no plans to support other intrinsics
// with deopt state.
LowerCallSiteWithDeoptBundle(&I, getValue(Callee), EHPadBB);
} else {
LowerCallTo(&I, getValue(Callee), false, EHPadBB);
}
// If the value of the invoke is used outside of its defining block, make it
// available as a virtual register.
@ -6100,9 +6116,22 @@ void SelectionDAGBuilder::visitCall(const CallInst &I) {
RenameFn,
DAG.getTargetLoweringInfo().getPointerTy(DAG.getDataLayout()));
// Check if we can potentially perform a tail call. More detailed checking is
// be done within LowerCallTo, after more information about the call is known.
LowerCallTo(&I, Callee, I.isTailCall());
#ifndef NDEBUG
// Deopt bundles are lowered in LowerCallSiteWithDeoptBundle, and we don't
// have to do anything here to lower funclet bundles.
for (unsigned i = 0, e = I.getNumOperandBundles(); i != e; ++i)
assert((I.getOperandBundleAt(i).isDeoptOperandBundle() ||
I.getOperandBundleAt(i).isFuncletOperandBundle()) &&
"Cannot lower calls with arbitrary operand bundles!");
#endif
if (I.countOperandBundlesOfType(LLVMContext::OB_deopt))
LowerCallSiteWithDeoptBundle(&I, Callee, nullptr);
else
// Check if we can potentially perform a tail call. More detailed checking
// is be done within LowerCallTo, after more information about the call is
// known.
LowerCallTo(&I, Callee, I.isTailCall());
}
namespace {

6
lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
View File

@ -772,12 +772,16 @@ public:
};
/// Lower \p SLI into a STATEPOINT instruction.
SDValue LowerAsStatepoint(StatepointLoweringInfo &SLI);
SDValue LowerAsSTATEPOINT(StatepointLoweringInfo &SLI);
// This function is responsible for the whole statepoint lowering process.
// It uniformly handles invoke and call statepoints.
void LowerStatepoint(ImmutableStatepoint Statepoint,
const BasicBlock *EHPadBB = nullptr);
void LowerCallSiteWithDeoptBundle(ImmutableCallSite CS, SDValue Callee,
const BasicBlock *EHPadBB);
private:
// Terminator instructions.
void visitRet(const ReturnInst &I);

74
lib/CodeGen/SelectionDAG/StatepointLowering.cpp
View File

@ -441,25 +441,30 @@ lowerStatepointMetaArgs(SmallVectorImpl<SDValue> &Ops,
// Lower the deopt and gc arguments for this statepoint. Layout will be:
// deopt argument length, deopt arguments.., gc arguments...
#ifndef NDEBUG
// Check that each of the gc pointer and bases we've gotten out of the
// safepoint is something the strategy thinks might be a pointer (or vector
// of pointers) into the GC heap. This is basically just here to help catch
// errors during statepoint insertion. TODO: This should actually be in the
// Verifier, but we can't get to the GCStrategy from there (yet).
GCStrategy &S = Builder.GFI->getStrategy();
for (const Value *V : SI.Bases) {
auto Opt = S.isGCManagedPointer(V->getType()->getScalarType());
if (Opt.hasValue()) {
assert(Opt.getValue() &&
"non gc managed base pointer found in statepoint");
if (auto *GFI = Builder.GFI) {
// Check that each of the gc pointer and bases we've gotten out of the
// safepoint is something the strategy thinks might be a pointer (or vector
// of pointers) into the GC heap. This is basically just here to help catch
// errors during statepoint insertion. TODO: This should actually be in the
// Verifier, but we can't get to the GCStrategy from there (yet).
GCStrategy &S = GFI->getStrategy();
for (const Value *V : SI.Bases) {
auto Opt = S.isGCManagedPointer(V->getType()->getScalarType());
if (Opt.hasValue()) {
assert(Opt.getValue() &&
"non gc managed base pointer found in statepoint");
}
}
}
for (const Value *V : SI.Ptrs) {
auto Opt = S.isGCManagedPointer(V->getType()->getScalarType());
if (Opt.hasValue()) {
assert(Opt.getValue() &&
"non gc managed derived pointer found in statepoint");
for (const Value *V : SI.Ptrs) {
auto Opt = S.isGCManagedPointer(V->getType()->getScalarType());
if (Opt.hasValue()) {
assert(Opt.getValue() &&
"non gc managed derived pointer found in statepoint");
}
}
} else {
assert(SI.Bases.empty() && "No gc specified, so cannot relocate pointers!");
assert(SI.Ptrs.empty() && "No gc specified, so cannot relocate pointers!");
}
#endif
@ -550,7 +555,7 @@ lowerStatepointMetaArgs(SmallVectorImpl<SDValue> &Ops,
}
}
SDValue SelectionDAGBuilder::LowerAsStatepoint(
SDValue SelectionDAGBuilder::LowerAsSTATEPOINT(
SelectionDAGBuilder::StatepointLoweringInfo &SI) {
// The basic scheme here is that information about both the original call and
// the safepoint is encoded in the CallInst. We create a temporary call and
@ -794,7 +799,7 @@ SelectionDAGBuilder::LowerStatepoint(ImmutableStatepoint ISP,
SI.NumPatchBytes = ISP.getNumPatchBytes();
SI.EHPadBB = EHPadBB;
SDValue ReturnValue = LowerAsStatepoint(SI);
SDValue ReturnValue = LowerAsSTATEPOINT(SI);
// Export the result value if needed
const Instruction *GCResult = ISP.getGCResult();
@ -830,6 +835,37 @@ SelectionDAGBuilder::LowerStatepoint(ImmutableStatepoint ISP,
}
}
void SelectionDAGBuilder::LowerCallSiteWithDeoptBundle(
ImmutableCallSite CS, SDValue Callee, const BasicBlock *EHPadBB) {
assert(CS.getNumOperandBundles() == 1 &&
"Only deopt operand bundles can be lowered!");
StatepointLoweringInfo SI(DAG);
unsigned ArgBeginIndex = CS.arg_begin() - CS.getInstruction()->op_begin();
populateCallLoweringInfo(SI.CLI, CS, ArgBeginIndex, CS.getNumArgOperands(),
Callee, CS.getType(), false);
auto DeoptBundle = CS.getOperandBundleAt(0);
assert(DeoptBundle.getTagID() == LLVMContext::OB_deopt && "Should be!");
unsigned DefaultID = StatepointDirectives::DeoptBundleStatepointID;
auto SD = parseStatepointDirectivesFromAttrs(CS.getAttributes());
SI.ID = SD.StatepointID.getValueOr(DefaultID);
SI.NumPatchBytes = SD.NumPatchBytes.getValueOr(0);
SI.DeoptState =
ArrayRef<const Use>(DeoptBundle.Inputs.begin(), DeoptBundle.Inputs.end());
SI.StatepointFlags = static_cast<uint64_t>(StatepointFlags::None);
SI.EHPadBB = EHPadBB;
if (SDValue ReturnVal = LowerAsSTATEPOINT(SI)) {
const Instruction *Inst = CS.getInstruction();
ReturnVal = lowerRangeToAssertZExt(DAG, *Inst, ReturnVal);
setValue(Inst, ReturnVal);
}
}
void SelectionDAGBuilder::visitGCResult(const CallInst &CI) {
// The result value of the gc_result is simply the result of the actual
// call. We've already emitted this, so just grab the value.

104
test/CodeGen/X86/deopt-bundles.ll Normal file
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@ -0,0 +1,104 @@
; RUN: llc -debug-only=stackmaps < %s 2>&1 | FileCheck %s
; RUN: llc -debug-only=stackmaps -O3 < %s 2>&1 | FileCheck %s
; REQUIRES: asserts
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.11.0"
; CHECK: Stack Maps: callsite 2882400015
; CHECK-NEXT: Stack Maps: has 4 locations
; CHECK-NEXT: Stack Maps: Loc 0: Constant 0 [encoding: .byte 4, .byte 8, .short 0, .int 0]
; CHECK-NEXT: Stack Maps: Loc 1: Constant 0 [encoding: .byte 4, .byte 8, .short 0, .int 0]
; CHECK-NEXT: Stack Maps: Loc 2: Constant 1 [encoding: .byte 4, .byte 8, .short 0, .int 1]
; CHECK-NEXT: Stack Maps: Loc 3: Constant 0 [encoding: .byte 4, .byte 8, .short 0, .int 0]
; CHECK-NEXT: Stack Maps: has 0 live-out registers
; CHECK-NEXT: Stack Maps: callsite 4242
; CHECK-NEXT: Stack Maps: has 4 locations
; CHECK-NEXT: Stack Maps: Loc 0: Constant 0 [encoding: .byte 4, .byte 8, .short 0, .int 0]
; CHECK-NEXT: Stack Maps: Loc 1: Constant 0 [encoding: .byte 4, .byte 8, .short 0, .int 0]
; CHECK-NEXT: Stack Maps: Loc 2: Constant 1 [encoding: .byte 4, .byte 8, .short 0, .int 1]
; CHECK-NEXT: Stack Maps: Loc 3: Constant 1 [encoding: .byte 4, .byte 8, .short 0, .int 1]
; CHECK-NEXT: Stack Maps: has 0 live-out registers
; CHECK-NEXT: Stack Maps: callsite 2882400015
; CHECK-NEXT: Stack Maps: has 4 locations
; CHECK-NEXT: Stack Maps: Loc 0: Constant 0 [encoding: .byte 4, .byte 8, .short 0, .int 0]
; CHECK-NEXT: Stack Maps: Loc 1: Constant 0 [encoding: .byte 4, .byte 8, .short 0, .int 0]
; CHECK-NEXT: Stack Maps: Loc 2: Constant 1 [encoding: .byte 4, .byte 8, .short 0, .int 1]
; CHECK-NEXT: Stack Maps: Loc 3: Constant 2 [encoding: .byte 4, .byte 8, .short 0, .int 2]
; CHECK-NEXT: Stack Maps: has 0 live-out registers
; CHECK-NEXT: Stack Maps: callsite 2882400015
; CHECK-NEXT: Stack Maps: has 4 locations
; CHECK-NEXT: Stack Maps: Loc 0: Constant 0 [encoding: .byte 4, .byte 8, .short 0, .int 0]
; CHECK-NEXT: Stack Maps: Loc 1: Constant 0 [encoding: .byte 4, .byte 8, .short 0, .int 0]
; CHECK-NEXT: Stack Maps: Loc 2: Constant 1 [encoding: .byte 4, .byte 8, .short 0, .int 1]
; CHECK-NEXT: Stack Maps: Loc 3: Constant 3 [encoding: .byte 4, .byte 8, .short 0, .int 3]
; CHECK-NEXT: Stack Maps: has 0 live-out registers
declare i32 @callee_0()
declare i32 @callee_1(i32)
define i32 @caller_0() {
; CHECK-LABEL: _caller_0
entry:
%v = call i32 @callee_0() [ "deopt"(i32 0) ]
%v2 = add i32 %v, 1
ret i32 %v2
; CHECK: callq _callee_0
; CHECK: incl %eax
; CHECK: retq
}
define i32 @caller_1() {
; CHECK-LABEL: _caller_1
entry:
%v = call i32 @callee_1(i32 42) "statepoint-id"="4242" [ "deopt"(i32 1) ]
ret i32 %v
; CHECK: callq _callee_1
; CHECK: popq %rcx
; CHECK: retq
}
define i32 @invoker_0() personality i8 0 {
; CHECK-LABEL: _invoker_0
entry:
%v = invoke i32 @callee_0() [ "deopt"(i32 2) ]
to label %normal unwind label %uw
normal:
ret i32 %v
uw:
%ehvals = landingpad { i8*, i32 }
cleanup
ret i32 1
; CHECK: callq _callee_0
; CHECK: popq %rcx
; CHECK: retq
; CHECK: movl $1, %eax
; CHECK: popq %rcx
; CHECK: retq
}
define i32 @invoker_1() personality i8 0 {
; CHECK-LABEL: _invoker_1
entry:
%v = invoke i32 @callee_1(i32 45) "statepoint-num-patch-bytes"="9" [ "deopt"(i32 3) ]
to label %normal unwind label %uw
normal:
ret i32 %v
uw:
%ehvals = landingpad { i8*, i32 }
cleanup
ret i32 1
; CHECK: movl $45, %edi
; CHECK: nopw 512(%rax,%rax)
; CHECK: popq %rcx
; CHECK: retq
; CHECK: movl $1, %eax
; CHECK: popq %rcx
; CHECK: retq
}