| //===- OutputSegment.h -----------------------------------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "OutputSegment.h" |
| #include "InputChunks.h" |
| #include "lld/Common/Memory.h" |
| |
| #define DEBUG_TYPE "lld" |
| |
| using namespace llvm; |
| using namespace llvm::wasm; |
| |
| namespace lld { |
| |
| namespace wasm { |
| |
| void OutputSegment::addInputSegment(InputChunk *inSeg) { |
| alignment = std::max(alignment, inSeg->alignment); |
| inputSegments.push_back(inSeg); |
| size = llvm::alignTo(size, 1ULL << inSeg->alignment); |
| LLVM_DEBUG(dbgs() << "addInputSegment: " << inSeg->getName() |
| << " oname=" << name << " size=" << inSeg->getSize() |
| << " align=" << inSeg->alignment << " at:" << size << "\n"); |
| inSeg->outputSeg = this; |
| inSeg->outputSegmentOffset = size; |
| size += inSeg->getSize(); |
| } |
| |
| // This function scans over the input segments. |
| // |
| // It removes MergeInputChunks from the input section array and adds |
| // new synthetic sections at the location of the first input section |
| // that it replaces. It then finalizes each synthetic section in order |
| // to compute an output offset for each piece of each input section. |
| void OutputSegment::finalizeInputSegments() { |
| LLVM_DEBUG(llvm::dbgs() << "finalizeInputSegments: " << name << "\n"); |
| std::vector<SyntheticMergedChunk *> mergedSegments; |
| std::vector<InputChunk *> newSegments; |
| for (InputChunk *s : inputSegments) { |
| MergeInputChunk *ms = dyn_cast<MergeInputChunk>(s); |
| if (!ms) { |
| newSegments.push_back(s); |
| continue; |
| } |
| |
| // A segment should not make it here unless its alive |
| assert(ms->live); |
| |
| auto i = llvm::find_if(mergedSegments, [=](SyntheticMergedChunk *seg) { |
| return seg->flags == ms->flags && seg->alignment == ms->alignment; |
| }); |
| if (i == mergedSegments.end()) { |
| LLVM_DEBUG(llvm::dbgs() << "new merge segment: " << name |
| << " alignment=" << ms->alignment << "\n"); |
| auto *syn = make<SyntheticMergedChunk>(name, ms->alignment, ms->flags); |
| syn->outputSeg = this; |
| mergedSegments.push_back(syn); |
| i = std::prev(mergedSegments.end()); |
| newSegments.push_back(syn); |
| } else { |
| LLVM_DEBUG(llvm::dbgs() << "adding to merge segment: " << name << "\n"); |
| } |
| (*i)->addMergeChunk(ms); |
| } |
| |
| for (auto *ms : mergedSegments) |
| ms->finalizeContents(); |
| |
| inputSegments = newSegments; |
| size = 0; |
| for (InputChunk *seg : inputSegments) { |
| size = llvm::alignTo(size, 1ULL << seg->alignment); |
| LLVM_DEBUG(llvm::dbgs() << "outputSegmentOffset set: " << seg->getName() |
| << " -> " << size << "\n"); |
| seg->outputSegmentOffset = size; |
| size += seg->getSize(); |
| } |
| } |
| |
| } // namespace wasm |
| } // namespace lld |