f60eed9344
Try to reduce individual subtarget features in the "target-features" attribute. This attempts a textual removal of the fields in the string, not a semantic removal. Typically there's a lot of redundant feature spam in the feature list implied by the target-cpu (which I really wish clang would stop emitting). If we could parse these out, we could easily drop the fields without testing anything.
57 lines
1.9 KiB
C++
57 lines
1.9 KiB
C++
//===- ReduceTargetFeaturesAttr.cpp - Specialized Delta Pass --------------===//
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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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// Attempt to remove individual elements of the "target-features" attribute on
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// functions.
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//
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//===----------------------------------------------------------------------===//
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#include "ReduceTargetFeaturesAttr.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/IR/Function.h"
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// TODO: We could maybe do better if we did a semantic parse of the attributes
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// through MCSubtargetInfo. Features can be flipped on and off in the string,
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// some are implied by target-cpu and can't be meaningfully re-added.
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void llvm::reduceTargetFeaturesAttrDeltaPass(Oracle &O,
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ReducerWorkItem &WorkItem) {
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Module &M = WorkItem.getModule();
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SmallString<256> NewValueString;
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SmallVector<StringRef, 32> SplitFeatures;
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for (Function &F : M) {
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Attribute TargetFeaturesAttr = F.getFnAttribute("target-features");
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if (!TargetFeaturesAttr.isValid())
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continue;
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StringRef TargetFeatures = TargetFeaturesAttr.getValueAsString();
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TargetFeatures.split(SplitFeatures, ',', /*MaxSplit=*/-1,
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/*KeepEmpty=*/false);
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ListSeparator LS(",");
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{
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raw_svector_ostream OS(NewValueString);
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for (StringRef Feature : SplitFeatures) {
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if (O.shouldKeep())
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OS << LS << Feature;
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}
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}
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if (NewValueString.empty())
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F.removeFnAttr("target-features");
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else
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F.addFnAttr("target-features", NewValueString);
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SplitFeatures.clear();
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NewValueString.clear();
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}
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}
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