1 //===- ConstantPool.h - Keep track of assembler-generated ------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the ConstantPool and AssemblerConstantPools classes.
12 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_MC_CONSTANTPOOL_H
16 #define LLVM_MC_CONSTANTPOOL_H
18 #include "llvm/ADT/SmallVector.h"
25 // A class to keep track of assembler-generated constant pools that are use to
26 // implement the ldr-pseudo.
28 typedef SmallVector<std::pair<MCSymbol *, const MCExpr *>, 4> EntryVecTy;
32 // Initialize a new empty constant pool
35 // Add a new entry to the constant pool in the next slot.
36 // \param Value is the new entry to put in the constant pool.
38 // \returns a MCExpr that references the newly inserted value
39 const MCExpr *addEntry(const MCExpr *Value, MCContext &Context);
41 // Emit the contents of the constant pool using the provided streamer.
42 void emitEntries(MCStreamer &Streamer);
44 // Return true if the constant pool is empty
48 class AssemblerConstantPools {
49 // Map type used to keep track of per-Section constant pools used by the
50 // ldr-pseudo opcode. The map associates a section to its constant pool. The
51 // constant pool is a vector of (label, value) pairs. When the ldr
52 // pseudo is parsed we insert a new (label, value) pair into the constant pool
53 // for the current section and add MCSymbolRefExpr to the new label as
54 // an opcode to the ldr. After we have parsed all the user input we
55 // output the (label, value) pairs in each constant pool at the end of the
58 // We use the MapVector for the map type to ensure stable iteration of
59 // the sections at the end of the parse. We need to iterate over the
60 // sections in a stable order to ensure that we have print the
61 // constant pools in a deterministic order when printing an assembly
63 typedef MapVector<const MCSection *, ConstantPool> ConstantPoolMapTy;
64 ConstantPoolMapTy ConstantPools;
67 AssemblerConstantPools() {}
68 ~AssemblerConstantPools() {}
70 void emitAll(MCStreamer &Streamer);
71 void emitForCurrentSection(MCStreamer &Streamer);
72 const MCExpr *addEntry(MCStreamer &Streamer, const MCExpr *Expr);
75 ConstantPool *getConstantPool(const MCSection *Section);
76 ConstantPool &getOrCreateConstantPool(const MCSection *Section);
78 } // end namespace llvm