97 lines
3.4 KiB
C++
97 lines
3.4 KiB
C++
//===-- TargetSelect.cpp - Target Chooser Code ----------------------------===//
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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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//
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// This just asks the TargetRegistry for the appropriate target to use, and
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// allows the user to specify a specific one on the commandline with -march=x,
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// -mcpu=y, and -mattr=a,-b,+c. Clients should initialize targets prior to
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// calling selectTarget().
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/Triple.h"
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#include "llvm/ExecutionEngine/ExecutionEngine.h"
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#include "llvm/IR/Module.h"
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#include "llvm/MC/SubtargetFeature.h"
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#include "llvm/MC/TargetRegistry.h"
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#include "llvm/Support/Host.h"
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#include "llvm/Target/TargetMachine.h"
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using namespace llvm;
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TargetMachine *EngineBuilder::selectTarget() {
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Triple TT;
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// MCJIT can generate code for remote targets, but the old JIT and Interpreter
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// must use the host architecture.
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if (WhichEngine != EngineKind::Interpreter && M)
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TT.setTriple(M->getTargetTriple());
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return selectTarget(TT, MArch, MCPU, MAttrs);
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}
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/// selectTarget - Pick a target either via -march or by guessing the native
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/// arch. Add any CPU features specified via -mcpu or -mattr.
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TargetMachine *EngineBuilder::selectTarget(const Triple &TargetTriple,
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StringRef MArch,
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StringRef MCPU,
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const SmallVectorImpl<std::string>& MAttrs) {
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Triple TheTriple(TargetTriple);
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if (TheTriple.getTriple().empty())
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TheTriple.setTriple(sys::getProcessTriple());
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// Adjust the triple to match what the user requested.
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const Target *TheTarget = nullptr;
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if (!MArch.empty()) {
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auto I = find_if(TargetRegistry::targets(),
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[&](const Target &T) { return MArch == T.getName(); });
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if (I == TargetRegistry::targets().end()) {
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if (ErrorStr)
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*ErrorStr = "No available targets are compatible with this -march, "
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"see -version for the available targets.\n";
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return nullptr;
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}
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TheTarget = &*I;
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// Adjust the triple to match (if known), otherwise stick with the
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// requested/host triple.
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Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
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if (Type != Triple::UnknownArch)
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TheTriple.setArch(Type);
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} else {
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std::string Error;
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TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Error);
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if (!TheTarget) {
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if (ErrorStr)
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*ErrorStr = Error;
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return nullptr;
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}
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}
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// Package up features to be passed to target/subtarget
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std::string FeaturesStr;
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if (!MAttrs.empty()) {
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SubtargetFeatures Features;
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for (unsigned i = 0; i != MAttrs.size(); ++i)
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Features.AddFeature(MAttrs[i]);
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FeaturesStr = Features.getString();
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}
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// Allocate a target...
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TargetMachine *Target =
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TheTarget->createTargetMachine(TheTriple.getTriple(), MCPU, FeaturesStr,
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Options, RelocModel, CMModel, OptLevel,
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/*JIT*/ true);
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Target->Options.EmulatedTLS = EmulatedTLS;
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Target->Options.ExplicitEmulatedTLS = true;
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assert(Target && "Could not allocate target machine!");
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return Target;
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}
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