ConstantPools.cpp revision cd81d94322a39503e4a3e87b6ee03d4fcb3465fb 
1//===- ConstantPools.cpp - ConstantPool class --*- C++ -*---------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the ConstantPool and  AssemblerConstantPools classes.
11//
12//===----------------------------------------------------------------------===//
13#include "llvm/ADT/MapVector.h"
14#include "llvm/MC/MCContext.h"
15#include "llvm/MC/MCExpr.h"
16#include "llvm/MC/MCStreamer.h"
17#include "llvm/MC/ConstantPools.h"
18
19using namespace llvm;
20//
21// ConstantPool implementation
22//
23// Emit the contents of the constant pool using the provided streamer.
24void ConstantPool::emitEntries(MCStreamer &Streamer) {
25  if (Entries.empty())
26    return;
27  Streamer.EmitCodeAlignment(4); // align to 4-byte address
28  Streamer.EmitDataRegion(MCDR_DataRegion);
29  for (EntryVecTy::const_iterator I = Entries.begin(), E = Entries.end();
30       I != E; ++I) {
31    Streamer.EmitLabel(I->first);
32    Streamer.EmitValue(I->second, 4);
33  }
34  Streamer.EmitDataRegion(MCDR_DataRegionEnd);
35  Entries.clear();
36}
37
38const MCExpr *ConstantPool::addEntry(const MCExpr *Value, MCContext &Context) {
39  MCSymbol *CPEntryLabel = Context.CreateTempSymbol();
40
41  Entries.push_back(std::make_pair(CPEntryLabel, Value));
42  return MCSymbolRefExpr::Create(CPEntryLabel, Context);
43}
44
45bool ConstantPool::empty() { return Entries.empty(); }
46
47//
48// AssemblerConstantPools implementation
49//
50ConstantPool *
51AssemblerConstantPools::getConstantPool(const MCSection *Section) {
52  ConstantPoolMapTy::iterator CP = ConstantPools.find(Section);
53  if (CP == ConstantPools.end())
54    return nullptr;
55
56  return &CP->second;
57}
58
59ConstantPool &
60AssemblerConstantPools::getOrCreateConstantPool(const MCSection *Section) {
61  return ConstantPools[Section];
62}
63
64static void emitConstantPool(MCStreamer &Streamer, const MCSection *Section,
65                             ConstantPool &CP) {
66  if (!CP.empty()) {
67    Streamer.SwitchSection(Section);
68    CP.emitEntries(Streamer);
69  }
70}
71
72void AssemblerConstantPools::emitAll(MCStreamer &Streamer) {
73  // Dump contents of assembler constant pools.
74  for (ConstantPoolMapTy::iterator CPI = ConstantPools.begin(),
75                                   CPE = ConstantPools.end();
76       CPI != CPE; ++CPI) {
77    const MCSection *Section = CPI->first;
78    ConstantPool &CP = CPI->second;
79
80    emitConstantPool(Streamer, Section, CP);
81  }
82}
83
84void AssemblerConstantPools::emitForCurrentSection(MCStreamer &Streamer) {
85  const MCSection *Section = Streamer.getCurrentSection().first;
86  if (ConstantPool *CP = getConstantPool(Section)) {
87    emitConstantPool(Streamer, Section, *CP);
88  }
89}
90
91const MCExpr *AssemblerConstantPools::addEntry(MCStreamer &Streamer,
92                                               const MCExpr *Expr) {
93  const MCSection *Section = Streamer.getCurrentSection().first;
94  return getOrCreateConstantPool(Section).addEntry(Expr, Streamer.getContext());
95}
96