src/llvm/lib/MC/ConstantPools.cpp

   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/ConstantPools.h"
  15 #include "llvm/MC/MCContext.h"
  16 #include "llvm/MC/MCExpr.h"
  17 #include "llvm/MC/MCStreamer.h"
  18
  19 using namespace llvm;
  20 //
  21 // ConstantPool implementation
  22 //
  23 // Emit the contents of the constant pool using the provided streamer.
  24 void ConstantPool::emitEntries(MCStreamer &Streamer) {
  25   if (Entries.empty())
  26     return;
  27   Streamer.EmitDataRegion(MCDR_DataRegion);
  28   for (EntryVecTy::const_iterator I = Entries.begin(), E = Entries.end();
  29        I != E; ++I) {
  30     Streamer.EmitCodeAlignment(I->Size); // align naturally
  31     Streamer.EmitLabel(I->Label);
  32     Streamer.EmitValue(I->Value, I->Size);
  33   }
  34   Streamer.EmitDataRegion(MCDR_DataRegionEnd);
  35   Entries.clear();
  36 }
  37
  38 const MCExpr *ConstantPool::addEntry(const MCExpr *Value, MCContext &Context,
  39                                      unsigned Size) {
  40   MCSymbol *CPEntryLabel = Context.CreateTempSymbol();
  41
  42   Entries.push_back(ConstantPoolEntry(CPEntryLabel, Value, Size));
  43   return MCSymbolRefExpr::Create(CPEntryLabel, Context);
  44 }
  45
  46 bool ConstantPool::empty() { return Entries.empty(); }
  47
  48 //
  49 // AssemblerConstantPools implementation
  50 //
  51 ConstantPool *
  52 AssemblerConstantPools::getConstantPool(const MCSection *Section) {
  53   ConstantPoolMapTy::iterator CP = ConstantPools.find(Section);
  54   if (CP == ConstantPools.end())
  55     return nullptr;
  56
  57   return &CP->second;
  58 }
  59
  60 ConstantPool &
  61 AssemblerConstantPools::getOrCreateConstantPool(const MCSection *Section) {
  62   return ConstantPools[Section];
  63 }
  64
  65 static void emitConstantPool(MCStreamer &Streamer, const MCSection *Section,
  66                              ConstantPool &CP) {
  67   if (!CP.empty()) {
  68     Streamer.SwitchSection(Section);
  69     CP.emitEntries(Streamer);
  70   }
  71 }
  72
  73 void AssemblerConstantPools::emitAll(MCStreamer &Streamer) {
  74   // Dump contents of assembler constant pools.
  75   for (ConstantPoolMapTy::iterator CPI = ConstantPools.begin(),
  76                                    CPE = ConstantPools.end();
  77        CPI != CPE; ++CPI) {
  78     const MCSection *Section = CPI->first;
  79     ConstantPool &CP = CPI->second;
  80
  81     emitConstantPool(Streamer, Section, CP);
  82   }
  83 }
  84
  85 void AssemblerConstantPools::emitForCurrentSection(MCStreamer &Streamer) {
  86   const MCSection *Section = Streamer.getCurrentSection().first;
  87   if (ConstantPool *CP = getConstantPool(Section)) {
  88     emitConstantPool(Streamer, Section, *CP);
  89   }
  90 }
  91
  92 const MCExpr *AssemblerConstantPools::addEntry(MCStreamer &Streamer,
  93                                                const MCExpr *Expr,
  94                                                unsigned Size) {
  95   const MCSection *Section = Streamer.getCurrentSection().first;
  96   return getOrCreateConstantPool(Section).addEntry(Expr, Streamer.getContext(),
  97                                                    Size);
  98 }