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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77115 91177308-0d34-0410-b5e6-96231b3b80d8
95 lines
2.9 KiB
C++
95 lines
2.9 KiB
C++
//===--- TargetRegistry.cpp - Target registration -------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Target/TargetRegistry.h"
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#include "llvm/System/Host.h"
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#include <cassert>
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using namespace llvm;
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// Clients are responsible for avoid race conditions in registration.
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static Target *FirstTarget = 0;
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TargetRegistry::iterator TargetRegistry::begin() {
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return iterator(FirstTarget);
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}
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const Target *TargetRegistry::lookupTarget(const std::string &TT,
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bool FallbackToHost,
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bool RequireJIT,
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std::string &Error) {
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// Provide special warning when no targets are initialized.
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if (begin() == end()) {
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Error = "Unable to find target for this triple (no targets are registered)";
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return 0;
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}
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const Target *Best = 0, *EquallyBest = 0;
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unsigned BestQuality = 0;
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for (iterator it = begin(), ie = end(); it != ie; ++it) {
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if (RequireJIT && !it->hasJIT())
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continue;
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if (unsigned Qual = it->TripleMatchQualityFn(TT)) {
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if (!Best || Qual > BestQuality) {
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Best = &*it;
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EquallyBest = 0;
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BestQuality = Qual;
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} else if (Qual == BestQuality)
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EquallyBest = &*it;
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}
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}
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// FIXME: Hack. If we only have an extremely weak match and the client
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// requested to fall back to the host, then ignore it and try again.
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if (BestQuality == 1 && FallbackToHost)
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Best = 0;
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// Fallback to the host triple if we didn't find anything.
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if (!Best && FallbackToHost)
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return lookupTarget(sys::getHostTriple(), false, RequireJIT, Error);
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if (!Best) {
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Error = "No available targets are compatible with this triple";
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return 0;
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}
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// Otherwise, take the best target, but make sure we don't have two equally
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// good best targets.
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if (EquallyBest) {
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Error = std::string("Cannot choose between targets \"") +
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Best->Name + "\" and \"" + EquallyBest->Name + "\"";
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return 0;
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}
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return Best;
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}
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void TargetRegistry::RegisterTarget(Target &T,
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const char *Name,
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const char *ShortDesc,
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Target::TripleMatchQualityFnTy TQualityFn,
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bool HasJIT) {
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assert(Name && ShortDesc && TQualityFn &&
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"Missing required target information!");
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// Check if this target has already been initialized, we allow this as a
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// convenience to some clients.
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if (T.Name)
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return;
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// Add to the list of targets.
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T.Next = FirstTarget;
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FirstTarget = &T;
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T.Name = Name;
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T.ShortDesc = ShortDesc;
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T.TripleMatchQualityFn = TQualityFn;
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T.HasJIT = HasJIT;
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}
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