llvm/lib/MC/ConstantPools.cpp
Rafael Espindola 7521964d28 Move alignment from MCSectionData to MCSection.
This starts merging MCSection and MCSectionData.

There are a few issues with the current split between MCSection and
MCSectionData.

* It optimizes the the not as important case. We want the production
of .o files to be really fast, but the split puts the information used
for .o emission in a separate data structure.

* The ELF/COFF/MachO hierarchy is not represented in MCSectionData,
leading to some ad-hoc ways to represent the various flags.

* It makes it harder to remember where each item is.

The attached patch starts merging the two by moving the alignment from
MCSectionData to MCSection.

Most of the patch is actually just dropping 'const', since
MCSectionData is mutable, but MCSection was not.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237936 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-21 19:20:38 +00:00

98 lines
3.2 KiB
C++

//===- ConstantPools.cpp - ConstantPool class --*- C++ -*---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the ConstantPool and AssemblerConstantPools classes.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/MapVector.h"
#include "llvm/MC/ConstantPools.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCStreamer.h"
using namespace llvm;
//
// ConstantPool implementation
//
// Emit the contents of the constant pool using the provided streamer.
void ConstantPool::emitEntries(MCStreamer &Streamer) {
if (Entries.empty())
return;
Streamer.EmitDataRegion(MCDR_DataRegion);
for (EntryVecTy::const_iterator I = Entries.begin(), E = Entries.end();
I != E; ++I) {
Streamer.EmitCodeAlignment(I->Size); // align naturally
Streamer.EmitLabel(I->Label);
Streamer.EmitValue(I->Value, I->Size);
}
Streamer.EmitDataRegion(MCDR_DataRegionEnd);
Entries.clear();
}
const MCExpr *ConstantPool::addEntry(const MCExpr *Value, MCContext &Context,
unsigned Size) {
MCSymbol *CPEntryLabel = Context.createTempSymbol();
Entries.push_back(ConstantPoolEntry(CPEntryLabel, Value, Size));
return MCSymbolRefExpr::Create(CPEntryLabel, Context);
}
bool ConstantPool::empty() { return Entries.empty(); }
//
// AssemblerConstantPools implementation
//
ConstantPool *AssemblerConstantPools::getConstantPool(MCSection *Section) {
ConstantPoolMapTy::iterator CP = ConstantPools.find(Section);
if (CP == ConstantPools.end())
return nullptr;
return &CP->second;
}
ConstantPool &
AssemblerConstantPools::getOrCreateConstantPool(MCSection *Section) {
return ConstantPools[Section];
}
static void emitConstantPool(MCStreamer &Streamer, MCSection *Section,
ConstantPool &CP) {
if (!CP.empty()) {
Streamer.SwitchSection(Section);
CP.emitEntries(Streamer);
}
}
void AssemblerConstantPools::emitAll(MCStreamer &Streamer) {
// Dump contents of assembler constant pools.
for (ConstantPoolMapTy::iterator CPI = ConstantPools.begin(),
CPE = ConstantPools.end();
CPI != CPE; ++CPI) {
MCSection *Section = CPI->first;
ConstantPool &CP = CPI->second;
emitConstantPool(Streamer, Section, CP);
}
}
void AssemblerConstantPools::emitForCurrentSection(MCStreamer &Streamer) {
MCSection *Section = Streamer.getCurrentSection().first;
if (ConstantPool *CP = getConstantPool(Section)) {
emitConstantPool(Streamer, Section, *CP);
}
}
const MCExpr *AssemblerConstantPools::addEntry(MCStreamer &Streamer,
const MCExpr *Expr,
unsigned Size) {
MCSection *Section = Streamer.getCurrentSection().first;
return getOrCreateConstantPool(Section).addEntry(Expr, Streamer.getContext(),
Size);
}