mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-10-19 02:52:53 +02:00
Reland "[WebAssembly] Eliminate range checks on br_tables"
This reverts commit 755a89591528b692315ad0325347e2fd4637271b. Although I was not able to reproduce any test failures locally, aheejin was able to reproduce them and found a fix, applied here.
This commit is contained in:
Thomas Lively
parent
8b6f187cd4
commit
e9d1d2ae6e
@ -24,6 +24,7 @@ add_llvm_target(WebAssemblyCodeGen
|
||||
WebAssemblyExceptionInfo.cpp
|
||||
WebAssemblyExplicitLocals.cpp
|
||||
WebAssemblyFastISel.cpp
|
||||
WebAssemblyFixBrTableDefaults.cpp
|
||||
WebAssemblyFixIrreducibleControlFlow.cpp
|
||||
WebAssemblyFixFunctionBitcasts.cpp
|
||||
WebAssemblyFrameLowering.cpp
|
||||
|
||||
@ -459,6 +459,18 @@ inline bool isCallIndirect(unsigned Opc) {
|
||||
}
|
||||
}
|
||||
|
||||
inline bool isBrTable(const MachineInstr &MI) {
|
||||
switch (MI.getOpcode()) {
|
||||
case WebAssembly::BR_TABLE_I32:
|
||||
case WebAssembly::BR_TABLE_I32_S:
|
||||
case WebAssembly::BR_TABLE_I64:
|
||||
case WebAssembly::BR_TABLE_I64_S:
|
||||
return true;
|
||||
default:
|
||||
return false;
|
||||
}
|
||||
}
|
||||
|
||||
inline bool isMarker(unsigned Opc) {
|
||||
switch (Opc) {
|
||||
case WebAssembly::BLOCK:
|
||||
|
||||
@ -44,6 +44,7 @@ FunctionPass *createWebAssemblyOptimizeLiveIntervals();
|
||||
FunctionPass *createWebAssemblyMemIntrinsicResults();
|
||||
FunctionPass *createWebAssemblyRegStackify();
|
||||
FunctionPass *createWebAssemblyRegColoring();
|
||||
FunctionPass *createWebAssemblyFixBrTableDefaults();
|
||||
FunctionPass *createWebAssemblyFixIrreducibleControlFlow();
|
||||
FunctionPass *createWebAssemblyLateEHPrepare();
|
||||
FunctionPass *createWebAssemblyCFGSort();
|
||||
@ -68,6 +69,7 @@ void initializeWebAssemblyOptimizeLiveIntervalsPass(PassRegistry &);
|
||||
void initializeWebAssemblyMemIntrinsicResultsPass(PassRegistry &);
|
||||
void initializeWebAssemblyRegStackifyPass(PassRegistry &);
|
||||
void initializeWebAssemblyRegColoringPass(PassRegistry &);
|
||||
void initializeWebAssemblyFixBrTableDefaultsPass(PassRegistry &);
|
||||
void initializeWebAssemblyFixIrreducibleControlFlowPass(PassRegistry &);
|
||||
void initializeWebAssemblyLateEHPreparePass(PassRegistry &);
|
||||
void initializeWebAssemblyExceptionInfoPass(PassRegistry &);
|
||||
|
||||
129
lib/Target/WebAssembly/WebAssemblyFixBrTableDefaults.cpp
Normal file
129
lib/Target/WebAssembly/WebAssemblyFixBrTableDefaults.cpp
Normal file
@ -0,0 +1,129 @@
|
||||
//=- WebAssemblyFixBrTableDefaults.cpp - Fix br_table default branch targets -//
|
||||
//
|
||||
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
||||
// See https://llvm.org/LICENSE.txt for license information.
|
||||
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
||||
//
|
||||
//===----------------------------------------------------------------------===//
|
||||
///
|
||||
/// \file This file implements a pass that eliminates redundant range checks
|
||||
/// guarding br_table instructions. Since jump tables on most targets cannot
|
||||
/// handle out of range indices, LLVM emits these checks before most jump
|
||||
/// tables. But br_table takes a default branch target as an argument, so it
|
||||
/// does not need the range checks.
|
||||
///
|
||||
//===----------------------------------------------------------------------===//
|
||||
|
||||
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
|
||||
#include "WebAssembly.h"
|
||||
#include "llvm/CodeGen/MachineFunction.h"
|
||||
#include "llvm/CodeGen/MachineFunctionPass.h"
|
||||
#include "llvm/CodeGen/MachineRegisterInfo.h"
|
||||
#include "llvm/Pass.h"
|
||||
|
||||
using namespace llvm;
|
||||
|
||||
#define DEBUG_TYPE "wasm-fix-br-table-defaults"
|
||||
|
||||
namespace {
|
||||
|
||||
class WebAssemblyFixBrTableDefaults final : public MachineFunctionPass {
|
||||
StringRef getPassName() const override {
|
||||
return "WebAssembly Fix br_table Defaults";
|
||||
}
|
||||
|
||||
bool runOnMachineFunction(MachineFunction &MF) override;
|
||||
|
||||
public:
|
||||
static char ID; // Pass identification, replacement for typeid
|
||||
WebAssemblyFixBrTableDefaults() : MachineFunctionPass(ID) {}
|
||||
};
|
||||
|
||||
char WebAssemblyFixBrTableDefaults::ID = 0;
|
||||
|
||||
// `MI` is a br_table instruction missing its default target argument. This
|
||||
// function finds and adds the default target argument and removes any redundant
|
||||
// range check preceding the br_table.
|
||||
MachineBasicBlock *fixBrTable(MachineInstr &MI, MachineBasicBlock *MBB,
|
||||
MachineFunction &MF) {
|
||||
// Get the header block, which contains the redundant range check.
|
||||
assert(MBB->pred_size() == 1 && "Expected a single guard predecessor");
|
||||
auto *HeaderMBB = *MBB->pred_begin();
|
||||
|
||||
// Find the conditional jump to the default target. If it doesn't exist, the
|
||||
// default target is unreachable anyway, so we can choose anything.
|
||||
auto JumpMII = --HeaderMBB->end();
|
||||
while (JumpMII->getOpcode() != WebAssembly::BR_IF &&
|
||||
JumpMII != HeaderMBB->begin()) {
|
||||
--JumpMII;
|
||||
}
|
||||
if (JumpMII->getOpcode() == WebAssembly::BR_IF) {
|
||||
// Install the default target and remove the jumps in the header.
|
||||
auto *DefaultMBB = JumpMII->getOperand(0).getMBB();
|
||||
assert(DefaultMBB != MBB && "Expected conditional jump to default target");
|
||||
MI.addOperand(MF, MachineOperand::CreateMBB(DefaultMBB));
|
||||
HeaderMBB->erase(JumpMII, HeaderMBB->end());
|
||||
} else {
|
||||
// Arbitrarily choose the first jump target as the default.
|
||||
auto *SomeMBB = MI.getOperand(1).getMBB();
|
||||
MI.addOperand(MachineOperand::CreateMBB(SomeMBB));
|
||||
}
|
||||
|
||||
// Splice the jump table into the header.
|
||||
HeaderMBB->splice(HeaderMBB->end(), MBB, MBB->begin(), MBB->end());
|
||||
|
||||
// Update CFG to skip the old jump table block. Remove shared successors
|
||||
// before transferring to avoid duplicated successors.
|
||||
HeaderMBB->removeSuccessor(MBB);
|
||||
for (auto &Succ : MBB->successors())
|
||||
if (HeaderMBB->isSuccessor(Succ))
|
||||
HeaderMBB->removeSuccessor(Succ);
|
||||
HeaderMBB->transferSuccessorsAndUpdatePHIs(MBB);
|
||||
|
||||
// Remove the old jump table block from the function
|
||||
MF.erase(MBB);
|
||||
|
||||
return HeaderMBB;
|
||||
}
|
||||
|
||||
bool WebAssemblyFixBrTableDefaults::runOnMachineFunction(MachineFunction &MF) {
|
||||
LLVM_DEBUG(dbgs() << "********** Fixing br_table Default Targets **********\n"
|
||||
"********** Function: "
|
||||
<< MF.getName() << '\n');
|
||||
|
||||
bool Changed = false;
|
||||
SmallPtrSet<MachineBasicBlock *, 16> MBBSet;
|
||||
for (auto &MBB : MF)
|
||||
MBBSet.insert(&MBB);
|
||||
|
||||
while (!MBBSet.empty()) {
|
||||
MachineBasicBlock *MBB = *MBBSet.begin();
|
||||
MBBSet.erase(MBB);
|
||||
for (auto &MI : *MBB) {
|
||||
if (WebAssembly::isBrTable(MI)) {
|
||||
auto *Fixed = fixBrTable(MI, MBB, MF);
|
||||
MBBSet.erase(Fixed);
|
||||
Changed = true;
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if (Changed) {
|
||||
// We rewrote part of the function; recompute relevant things.
|
||||
MF.RenumberBlocks();
|
||||
return true;
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
} // end anonymous namespace
|
||||
|
||||
INITIALIZE_PASS(WebAssemblyFixBrTableDefaults, DEBUG_TYPE,
|
||||
"Removes range checks and sets br_table default targets", false,
|
||||
false);
|
||||
|
||||
FunctionPass *llvm::createWebAssemblyFixBrTableDefaults() {
|
||||
return new WebAssemblyFixBrTableDefaults();
|
||||
}
|
||||
@ -1279,11 +1279,8 @@ SDValue WebAssemblyTargetLowering::LowerBR_JT(SDValue Op,
|
||||
for (auto MBB : MBBs)
|
||||
Ops.push_back(DAG.getBasicBlock(MBB));
|
||||
|
||||
// TODO: For now, we just pick something arbitrary for a default case for now.
|
||||
// We really want to sniff out the guard and put in the real default case (and
|
||||
// delete the guard).
|
||||
Ops.push_back(DAG.getBasicBlock(MBBs[0]));
|
||||
|
||||
// Do not add the default case for now. It will be added in
|
||||
// WebAssemblyFixBrTableDefaults.
|
||||
return DAG.getNode(WebAssemblyISD::BR_TABLE, DL, MVT::Other, Ops);
|
||||
}
|
||||
|
||||
|
||||
@ -406,6 +406,10 @@ bool WebAssemblyPassConfig::addInstSelector() {
|
||||
// it's inconvenient to collect. Collect it now, and update the immediate
|
||||
// operands.
|
||||
addPass(createWebAssemblySetP2AlignOperands());
|
||||
|
||||
// Eliminate range checks and add default targets to br_table instructions.
|
||||
addPass(createWebAssemblyFixBrTableDefaults());
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
|
||||
@ -382,14 +382,14 @@ if.end:
|
||||
|
||||
; CHECK-LABEL: test4:
|
||||
; CHECK-NEXT: .functype test4 (i32) -> (){{$}}
|
||||
; CHECK: block {{$}}
|
||||
; CHECK-NEXT: block {{$}}
|
||||
; CHECK: br_if 0, $pop{{[0-9]+}}{{$}}
|
||||
; CHECK: br 1{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_2:
|
||||
; CHECK-NEXT: block {{$}}
|
||||
; CHECK-NEXT: br_table $0, 1, 1, 1, 1, 1, 0{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_1:
|
||||
; CHECK-NEXT: end_block{{$}}
|
||||
; CHECK-NEXT: br_table $0, 0, 0, 0, 0, 0, 0{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_3:
|
||||
; CHECK-NEXT: i32.const $push[[C:[0-9]+]]=, 622{{$}}
|
||||
; CHECK-NEXT: i32.eq $drop=, $0, $pop[[C]]{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_2:
|
||||
; CHECK-NEXT: end_block{{$}}
|
||||
; CHECK-NEXT: return{{$}}
|
||||
define void @test4(i32 %t) {
|
||||
@ -649,20 +649,16 @@ end:
|
||||
; CHECK: br_if 0, {{[^,]+}}{{$}}
|
||||
; CHECK-NEXT: end_loop{{$}}
|
||||
; CHECK-NEXT: block {{$}}
|
||||
; CHECK: br_if 0, {{[^,]+}}{{$}}
|
||||
; CHECK: br 3{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_7:
|
||||
; CHECK-NEXT: end_block{{$}}
|
||||
; CHECK: block {{$}}
|
||||
; CHECK-NEXT: br_table $0, 0, 3, 1, 2, 0
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_8:
|
||||
; CHECK-NOT: br_if
|
||||
; CHECK: br_table $pop{{[^,]+}}, 0, 3, 1, 2, 3
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_6:
|
||||
; CHECK-NEXT: end_block{{$}}
|
||||
; CHECK-NEXT: end_loop{{$}}
|
||||
; CHECK-NEXT: return{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_9:
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_7:
|
||||
; CHECK-NEXT: end_block{{$}}
|
||||
; CHECK: br 0{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_10:
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_8:
|
||||
; CHECK-NEXT: end_loop{{$}}
|
||||
define void @test10() {
|
||||
bb0:
|
||||
@ -767,25 +763,22 @@ bb8:
|
||||
|
||||
; CHECK-LABEL: test12:
|
||||
; CHECK: .LBB{{[0-9]+}}_1:
|
||||
; CHECK-NEXT: block {{$}}
|
||||
; CHECK-NEXT: loop {{$}}
|
||||
; CHECK-NEXT: block {{$}}
|
||||
; CHECK-NEXT: block {{$}}
|
||||
; CHECK-NEXT: block {{$}}
|
||||
; CHECK: br_table {{[^,]+}}, 1, 3, 3, 3, 1, 0{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_2:
|
||||
; CHECK-NEXT: end_block{{$}}
|
||||
; CHECK: br_if 0, {{[^,]+}}{{$}}
|
||||
; CHECK: br_if 2, {{[^,]+}}{{$}}
|
||||
; CHECK: br_if 1, {{[^,]+}}{{$}}
|
||||
; CHECK-NEXT: br 2{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_4:
|
||||
; CHECK-NEXT: end_block{{$}}
|
||||
; CHECK-NEXT: br_table $2, 1, 0, 0, 0, 1, 1{{$}}
|
||||
; CHECK: br 0{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_5:
|
||||
; CHECK-NEXT: end_loop{{$}}
|
||||
; CHECK-NEXT: end_block{{$}}
|
||||
; CHECK-NEXT: return{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_6:
|
||||
; CHECK-NEXT: end_block{{$}}
|
||||
; CHECK: br 0{{$}}
|
||||
; CHECK-NEXT: .LBB{{[0-9]+}}_7:
|
||||
; CHECK-NEXT: end_loop{{$}}
|
||||
define void @test12(i8* %arg) {
|
||||
bb:
|
||||
br label %bb1
|
||||
|
||||
@ -13,20 +13,36 @@ target triple = "wasm32"
|
||||
|
||||
; Just check the barest skeleton of the structure
|
||||
; CHECK-LABEL: test1:
|
||||
; CHECK: block
|
||||
; CHECK: block
|
||||
; CHECK: block
|
||||
; CHECK: block
|
||||
; CHECK: i32.load
|
||||
; CHECK: i32.load $[[DEST:.+]]=
|
||||
; CHECK: i32.load
|
||||
; CHECK: i32.const
|
||||
; CHECK: i32.add $push[[DEST:.+]]=
|
||||
; CHECK: br_table $pop[[DEST]]
|
||||
; CHECK: end_block
|
||||
; CHECK: end_block
|
||||
; CHECK: end_block
|
||||
; CHECK: end_block
|
||||
; CHECK: loop
|
||||
; CHECK: block
|
||||
; CHECK: block
|
||||
; CHECK: block
|
||||
; CHECK: block
|
||||
; CHECK: br_table ${{[^,]+}}, 0, 1, 2, 2
|
||||
; CHECK: end_block
|
||||
; CHECK: end_block
|
||||
; CHECK: end_block
|
||||
; CHECK: block
|
||||
; CHECK: block
|
||||
; CHECK: br_table $[[DEST]]
|
||||
; CHECK: block
|
||||
; CHECK: br_table ${{[^,]+}}, 1, 2, 0
|
||||
; CHECK: end_block
|
||||
; CHECK: end_block
|
||||
; CHECK: end_block
|
||||
; CHECK: i32.load $[[DEST]]=
|
||||
; CHECK: end_loop
|
||||
|
||||
; CHECK: test1.targets:
|
||||
; CHECK-NEXT: .int32
|
||||
; CHECK-NEXT: .int32
|
||||
|
||||
@ -8,7 +8,7 @@ declare void @foo1()
|
||||
|
||||
; Tests if br_table is printed correctly with a tab.
|
||||
; CHECK-LABEL: test0:
|
||||
; CHECK: br_table {0, 1, 0, 1, 0}
|
||||
; CHECK: br_table {0, 1, 0, 1, 2}
|
||||
define void @test0(i32 %n) {
|
||||
entry:
|
||||
switch i32 %n, label %sw.epilog [
|
||||
|
||||
38
test/CodeGen/WebAssembly/switch-unreachable-default.ll
Normal file
38
test/CodeGen/WebAssembly/switch-unreachable-default.ll
Normal file
@ -0,0 +1,38 @@
|
||||
; RUN: llc < %s -asm-verbose=false -verify-machineinstrs | FileCheck %s
|
||||
|
||||
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
|
||||
target triple = "wasm32-unknown-unknown"
|
||||
|
||||
; Test that switches are lowered correctly in the presence of an
|
||||
; unreachable default branch target.
|
||||
|
||||
; CHECK-LABEL: foo:
|
||||
; CHECK-NEXT: .functype foo (i32) -> (i32)
|
||||
; CHECK-NEXT: block
|
||||
; CHECK-NEXT: block
|
||||
; CHECK-NEXT: local.get 0
|
||||
; CHECK-NEXT: br_table {0, 1, 0}
|
||||
; CHECK-NEXT: .LBB0_1:
|
||||
; CHECK-NEXT: end_block
|
||||
; CHECK-NEXT: i32.const 0
|
||||
; CHECK-NEXT: return
|
||||
; CHECK-NEXT: .LBB0_2:
|
||||
; CHECK-NEXT: end_block
|
||||
; CHECK-NEXT: i32.const 1
|
||||
; CHECK-NEXT: end_function
|
||||
define i32 @foo(i32 %x) {
|
||||
entry:
|
||||
switch i32 %x, label %unreachable [
|
||||
i32 0, label %bb0
|
||||
i32 1, label %bb1
|
||||
]
|
||||
|
||||
bb0:
|
||||
ret i32 0
|
||||
|
||||
bb1:
|
||||
ret i32 1
|
||||
|
||||
unreachable:
|
||||
unreachable
|
||||
}
|
||||
@ -21,20 +21,20 @@ declare void @foo5()
|
||||
; CHECK: block {{$}}
|
||||
; CHECK: block {{$}}
|
||||
; CHECK: block {{$}}
|
||||
; CHECK: br_table {{[^,]+}}, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 4, 5, 0{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_2:
|
||||
; CHECK: br_table {{[^,]+}}, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 4, 5, 6{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_1:
|
||||
; CHECK: call foo0{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_3:
|
||||
; CHECK: .LBB{{[0-9]+}}_2:
|
||||
; CHECK: call foo1{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_4:
|
||||
; CHECK: .LBB{{[0-9]+}}_3:
|
||||
; CHECK: call foo2{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_5:
|
||||
; CHECK: .LBB{{[0-9]+}}_4:
|
||||
; CHECK: call foo3{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_6:
|
||||
; CHECK: .LBB{{[0-9]+}}_5:
|
||||
; CHECK: call foo4{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_7:
|
||||
; CHECK: .LBB{{[0-9]+}}_6:
|
||||
; CHECK: call foo5{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_8:
|
||||
; CHECK: .LBB{{[0-9]+}}_7:
|
||||
; CHECK: return{{$}}
|
||||
define void @bar32(i32 %n) {
|
||||
entry:
|
||||
@ -101,20 +101,20 @@ sw.epilog: ; preds = %entry, %sw.bb.5, %s
|
||||
; CHECK: block {{$}}
|
||||
; CHECK: block {{$}}
|
||||
; CHECK: block {{$}}
|
||||
; CHECK: br_table {{[^,]+}}, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 4, 5, 0{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_2:
|
||||
; CHECK: br_table {{[^,]+}}, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 4, 5, 6{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_1:
|
||||
; CHECK: call foo0{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_3:
|
||||
; CHECK: .LBB{{[0-9]+}}_2:
|
||||
; CHECK: call foo1{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_4:
|
||||
; CHECK: .LBB{{[0-9]+}}_3:
|
||||
; CHECK: call foo2{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_5:
|
||||
; CHECK: .LBB{{[0-9]+}}_4:
|
||||
; CHECK: call foo3{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_6:
|
||||
; CHECK: .LBB{{[0-9]+}}_5:
|
||||
; CHECK: call foo4{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_7:
|
||||
; CHECK: .LBB{{[0-9]+}}_6:
|
||||
; CHECK: call foo5{{$}}
|
||||
; CHECK: .LBB{{[0-9]+}}_8:
|
||||
; CHECK: .LBB{{[0-9]+}}_7:
|
||||
; CHECK: return{{$}}
|
||||
define void @bar64(i64 %n) {
|
||||
entry:
|
||||
|
||||
Loading…
Reference in New Issue
Block a user