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 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_MC_CONSTANTPOOLS_H
15 #define LLVM_MC_CONSTANTPOOLS_H
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/MapVector.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/Support/SMLoc.h"
31 class MCSymbolRefExpr;
33 struct ConstantPoolEntry {
34 ConstantPoolEntry(MCSymbol *L, const MCExpr *Val, unsigned Sz, SMLoc Loc_)
35 : Label(L), Value(Val), Size(Sz), Loc(Loc_) {}
43 // A class to keep track of assembler-generated constant pools that are use to
44 // implement the ldr-pseudo.
46 using EntryVecTy = SmallVector<ConstantPoolEntry, 4>;
48 std::map<int64_t, const MCSymbolRefExpr *> CachedEntries;
51 // Initialize a new empty constant pool
52 ConstantPool() = default;
54 // Add a new entry to the constant pool in the next slot.
55 // \param Value is the new entry to put in the constant pool.
56 // \param Size is the size in bytes of the entry
58 // \returns a MCExpr that references the newly inserted value
59 const MCExpr *addEntry(const MCExpr *Value, MCContext &Context,
60 unsigned Size, SMLoc Loc);
62 // Emit the contents of the constant pool using the provided streamer.
63 void emitEntries(MCStreamer &Streamer);
65 // Return true if the constant pool is empty
71 class AssemblerConstantPools {
72 // Map type used to keep track of per-Section constant pools used by the
73 // ldr-pseudo opcode. The map associates a section to its constant pool. The
74 // constant pool is a vector of (label, value) pairs. When the ldr
75 // pseudo is parsed we insert a new (label, value) pair into the constant pool
76 // for the current section and add MCSymbolRefExpr to the new label as
77 // an opcode to the ldr. After we have parsed all the user input we
78 // output the (label, value) pairs in each constant pool at the end of the
81 // We use the MapVector for the map type to ensure stable iteration of
82 // the sections at the end of the parse. We need to iterate over the
83 // sections in a stable order to ensure that we have print the
84 // constant pools in a deterministic order when printing an assembly
86 using ConstantPoolMapTy = MapVector<MCSection *, ConstantPool>;
87 ConstantPoolMapTy ConstantPools;
90 void emitAll(MCStreamer &Streamer);
91 void emitForCurrentSection(MCStreamer &Streamer);
92 void clearCacheForCurrentSection(MCStreamer &Streamer);
93 const MCExpr *addEntry(MCStreamer &Streamer, const MCExpr *Expr,
94 unsigned Size, SMLoc Loc);
97 ConstantPool *getConstantPool(MCSection *Section);
98 ConstantPool &getOrCreateConstantPool(MCSection *Section);
101 } // end namespace llvm
103 #endif // LLVM_MC_CONSTANTPOOLS_H