84 lines
2.9 KiB
C++
84 lines
2.9 KiB
C++
//===- OutputSegment.h -----------------------------------------*- 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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#include "OutputSegment.h"
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#include "InputChunks.h"
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#include "lld/Common/Memory.h"
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#define DEBUG_TYPE "lld"
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using namespace llvm;
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using namespace llvm::wasm;
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namespace lld::wasm {
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void OutputSegment::addInputSegment(InputChunk *inSeg) {
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alignment = std::max(alignment, inSeg->alignment);
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inputSegments.push_back(inSeg);
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size = llvm::alignTo(size, 1ULL << inSeg->alignment);
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LLVM_DEBUG(dbgs() << "addInputSegment: " << inSeg->name << " oname=" << name
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<< " size=" << inSeg->getSize()
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<< " align=" << inSeg->alignment << " at:" << size << "\n");
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inSeg->outputSeg = this;
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inSeg->outputSegmentOffset = size;
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size += inSeg->getSize();
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}
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// This function scans over the input segments.
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//
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// It removes MergeInputChunks from the input section array and adds
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// new synthetic sections at the location of the first input section
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// that it replaces. It then finalizes each synthetic section in order
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// to compute an output offset for each piece of each input section.
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void OutputSegment::finalizeInputSegments() {
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LLVM_DEBUG(llvm::dbgs() << "finalizeInputSegments: " << name << "\n");
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std::vector<SyntheticMergedChunk *> mergedSegments;
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std::vector<InputChunk *> newSegments;
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for (InputChunk *s : inputSegments) {
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MergeInputChunk *ms = dyn_cast<MergeInputChunk>(s);
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if (!ms) {
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newSegments.push_back(s);
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continue;
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}
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// A segment should not make it here unless its alive
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assert(ms->live);
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auto i = llvm::find_if(mergedSegments, [=](SyntheticMergedChunk *seg) {
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return seg->flags == ms->flags && seg->alignment == ms->alignment;
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});
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if (i == mergedSegments.end()) {
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LLVM_DEBUG(llvm::dbgs() << "new merge segment: " << name
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<< " alignment=" << ms->alignment << "\n");
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auto *syn = make<SyntheticMergedChunk>(name, ms->alignment, ms->flags);
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syn->outputSeg = this;
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mergedSegments.push_back(syn);
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i = std::prev(mergedSegments.end());
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newSegments.push_back(syn);
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} else {
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LLVM_DEBUG(llvm::dbgs() << "adding to merge segment: " << name << "\n");
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}
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(*i)->addMergeChunk(ms);
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}
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for (auto *ms : mergedSegments)
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ms->finalizeContents();
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inputSegments = newSegments;
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size = 0;
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for (InputChunk *seg : inputSegments) {
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size = llvm::alignTo(size, 1ULL << seg->alignment);
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LLVM_DEBUG(llvm::dbgs() << "outputSegmentOffset set: " << seg->name
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<< " -> " << size << "\n");
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seg->outputSegmentOffset = size;
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size += seg->getSize();
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}
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}
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} // namespace lld::wasm
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