bb3f5e1fed
Following discussions in #110443, and the following earlier discussions in https://lists.llvm.org/pipermail/llvm-dev/2017-October/117907.html, https://reviews.llvm.org/D38482, https://reviews.llvm.org/D38489, this PR attempts to overhaul the `TargetMachine` and `LLVMTargetMachine` interface classes. More specifically: 1. Makes `TargetMachine` the only class implemented under `TargetMachine.h` in the `Target` library. 2. `TargetMachine` contains target-specific interface functions that relate to IR/CodeGen/MC constructs, whereas before (at least on paper) it was supposed to have only IR/MC constructs. Any Target that doesn't want to use the independent code generator simply does not implement them, and returns either `false` or `nullptr`. 3. Renames `LLVMTargetMachine` to `CodeGenCommonTMImpl`. This renaming aims to make the purpose of `LLVMTargetMachine` clearer. Its interface was moved under the CodeGen library, to further emphasis its usage in Targets that use CodeGen directly. 4. Makes `TargetMachine` the only interface used across LLVM and its projects. With these changes, `CodeGenCommonTMImpl` is simply a set of shared function implementations of `TargetMachine`, and CodeGen users don't need to static cast to `LLVMTargetMachine` every time they need a CodeGen-specific feature of the `TargetMachine`. 5. More importantly, does not change any requirements regarding library linking. cc @arsenm @aeubanks
98 lines
3.7 KiB
C++
98 lines
3.7 KiB
C++
//===-- ResetMachineFunctionPass.cpp - Reset Machine Function ----*- C++ -*-==//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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/// \file
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/// This file implements a pass that will conditionally reset a machine
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/// function as if it was just created. This is used to provide a fallback
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/// mechanism when GlobalISel fails, thus the condition for the reset to
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/// happen is that the MachineFunction has the FailedISel property.
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/ScopeExit.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/CodeGen/StackProtector.h"
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#include "llvm/IR/DiagnosticInfo.h"
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#include "llvm/InitializePasses.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Target/TargetMachine.h"
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using namespace llvm;
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#define DEBUG_TYPE "reset-machine-function"
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STATISTIC(NumFunctionsReset, "Number of functions reset");
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STATISTIC(NumFunctionsVisited, "Number of functions visited");
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namespace {
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class ResetMachineFunction : public MachineFunctionPass {
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/// Tells whether or not this pass should emit a fallback
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/// diagnostic when it resets a function.
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bool EmitFallbackDiag;
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/// Whether we should abort immediately instead of resetting the function.
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bool AbortOnFailedISel;
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public:
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static char ID; // Pass identification, replacement for typeid
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ResetMachineFunction(bool EmitFallbackDiag = false,
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bool AbortOnFailedISel = false)
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: MachineFunctionPass(ID), EmitFallbackDiag(EmitFallbackDiag),
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AbortOnFailedISel(AbortOnFailedISel) {}
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StringRef getPassName() const override { return "ResetMachineFunction"; }
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.addPreserved<StackProtector>();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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bool runOnMachineFunction(MachineFunction &MF) override {
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++NumFunctionsVisited;
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// No matter what happened, whether we successfully selected the function
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// or not, nothing is going to use the vreg types after us. Make sure they
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// disappear.
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auto ClearVRegTypesOnReturn =
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make_scope_exit([&MF]() { MF.getRegInfo().clearVirtRegTypes(); });
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if (MF.getProperties().hasProperty(
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MachineFunctionProperties::Property::FailedISel)) {
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if (AbortOnFailedISel)
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report_fatal_error("Instruction selection failed");
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LLVM_DEBUG(dbgs() << "Resetting: " << MF.getName() << '\n');
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++NumFunctionsReset;
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MF.reset();
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MF.initTargetMachineFunctionInfo(MF.getSubtarget());
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const TargetMachine &TM = MF.getTarget();
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// MRI callback for target specific initializations.
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TM.registerMachineRegisterInfoCallback(MF);
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if (EmitFallbackDiag) {
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const Function &F = MF.getFunction();
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DiagnosticInfoISelFallback DiagFallback(F);
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F.getContext().diagnose(DiagFallback);
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}
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return true;
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}
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return false;
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}
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};
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} // end anonymous namespace
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char ResetMachineFunction::ID = 0;
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INITIALIZE_PASS(ResetMachineFunction, DEBUG_TYPE,
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"Reset machine function if ISel failed", false, false)
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MachineFunctionPass *
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llvm::createResetMachineFunctionPass(bool EmitFallbackDiag = false,
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bool AbortOnFailedISel = false) {
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return new ResetMachineFunction(EmitFallbackDiag, AbortOnFailedISel);
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}
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