1a47f3f3db
This builds on top of commit 9d0754ada5dbbc0c009bcc2f7824488419cc5530
("[MC] Relax fragments eagerly") and relaxes fragments eagerly to
eliminate MCSection::HasLayout and `getFragmentOffset` overhead.
Note: The removed `#ifndef NDEBUG` code (disabled by default) in
X86AsmBackend::finishLayout was problematic, as (a) !NDEBUG and NDEBUG
builds evaluated fragment offsets at different times before this patch
(b) one iteration might not be sufficient to converge. There might be
some edge cases that it did not handle. Anyhow, this patch probably
makes it work for more cases.
88 lines
2.6 KiB
C++
88 lines
2.6 KiB
C++
//===- lib/MC/MCSection.cpp - Machine Code Section Representation ---------===//
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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 "llvm/MC/MCSection.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Config/llvm-config.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCFragment.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include <utility>
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using namespace llvm;
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MCSection::MCSection(SectionVariant V, StringRef Name, bool IsText,
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bool IsVirtual, MCSymbol *Begin)
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: Begin(Begin), BundleGroupBeforeFirstInst(false), HasInstructions(false),
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IsRegistered(false), IsText(IsText), IsVirtual(IsVirtual), Name(Name),
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Variant(V) {
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DummyFragment.setParent(this);
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// The initial subsection number is 0. Create a fragment list.
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CurFragList = &Subsections.emplace_back(0u, FragList{}).second;
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}
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MCSymbol *MCSection::getEndSymbol(MCContext &Ctx) {
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if (!End)
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End = Ctx.createTempSymbol("sec_end");
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return End;
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}
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bool MCSection::hasEnded() const { return End && End->isInSection(); }
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MCSection::~MCSection() {
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for (auto &[_, Chain] : Subsections) {
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for (MCFragment *X = Chain.Head, *Y; X; X = Y) {
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Y = X->Next;
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X->destroy();
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}
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}
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}
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void MCSection::setBundleLockState(BundleLockStateType NewState) {
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if (NewState == NotBundleLocked) {
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if (BundleLockNestingDepth == 0) {
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report_fatal_error("Mismatched bundle_lock/unlock directives");
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}
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if (--BundleLockNestingDepth == 0) {
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BundleLockState = NotBundleLocked;
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}
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return;
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}
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// If any of the directives is an align_to_end directive, the whole nested
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// group is align_to_end. So don't downgrade from align_to_end to just locked.
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if (BundleLockState != BundleLockedAlignToEnd) {
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BundleLockState = NewState;
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}
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++BundleLockNestingDepth;
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}
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StringRef MCSection::getVirtualSectionKind() const { return "virtual"; }
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#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
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LLVM_DUMP_METHOD void MCSection::dump() const {
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raw_ostream &OS = errs();
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OS << "<MCSection Name:" << getName();
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OS << " Fragments:[\n ";
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bool First = true;
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for (auto &F : *this) {
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if (First)
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First = false;
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else
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OS << ",\n ";
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F.dump();
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}
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OS << "]>";
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}
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#endif
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