LLVM 19.0.0git
ConstantPools.h
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1//===- ConstantPools.h - Keep track of assembler-generated ------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file declares the ConstantPool and AssemblerConstantPools classes.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_MC_CONSTANTPOOLS_H
14#define LLVM_MC_CONSTANTPOOLS_H
15
16#include "llvm/ADT/MapVector.h"
18#include "llvm/Support/SMLoc.h"
19#include <cstdint>
20#include <map>
21
22namespace llvm {
23
24class MCContext;
25class MCExpr;
26class MCSection;
27class MCStreamer;
28class MCSymbol;
29class MCSymbolRefExpr;
30
32 ConstantPoolEntry(MCSymbol *L, const MCExpr *Val, unsigned Sz, SMLoc Loc_)
33 : Label(L), Value(Val), Size(Sz), Loc(Loc_) {}
34
36 const MCExpr *Value;
37 unsigned Size;
39};
40
41// A class to keep track of assembler-generated constant pools that are use to
42// implement the ldr-pseudo.
45 EntryVecTy Entries;
46 std::map<int64_t, const MCSymbolRefExpr *> CachedConstantEntries;
48
49public:
50 // Initialize a new empty constant pool
51 ConstantPool() = default;
52
53 // Add a new entry to the constant pool in the next slot.
54 // \param Value is the new entry to put in the constant pool.
55 // \param Size is the size in bytes of the entry
56 //
57 // \returns a MCExpr that references the newly inserted value
58 const MCExpr *addEntry(const MCExpr *Value, MCContext &Context,
59 unsigned Size, SMLoc Loc);
60
61 // Emit the contents of the constant pool using the provided streamer.
62 void emitEntries(MCStreamer &Streamer);
63
64 // Return true if the constant pool is empty
65 bool empty();
66
67 void clearCache();
68};
69
71 // Map type used to keep track of per-Section constant pools used by the
72 // ldr-pseudo opcode. The map associates a section to its constant pool. The
73 // constant pool is a vector of (label, value) pairs. When the ldr
74 // pseudo is parsed we insert a new (label, value) pair into the constant pool
75 // for the current section and add MCSymbolRefExpr to the new label as
76 // an opcode to the ldr. After we have parsed all the user input we
77 // output the (label, value) pairs in each constant pool at the end of the
78 // section.
79 //
80 // We use the MapVector for the map type to ensure stable iteration of
81 // the sections at the end of the parse. We need to iterate over the
82 // sections in a stable order to ensure that we have print the
83 // constant pools in a deterministic order when printing an assembly
84 // file.
86 ConstantPoolMapTy ConstantPools;
87
88public:
89 void emitAll(MCStreamer &Streamer);
90 void emitForCurrentSection(MCStreamer &Streamer);
92 const MCExpr *addEntry(MCStreamer &Streamer, const MCExpr *Expr,
93 unsigned Size, SMLoc Loc);
94
95private:
96 ConstantPool *getConstantPool(MCSection *Section);
97 ConstantPool &getOrCreateConstantPool(MCSection *Section);
98};
99
100} // end namespace llvm
101
102#endif // LLVM_MC_CONSTANTPOOLS_H
uint64_t Size
This file implements a map that provides insertion order iteration.
This file defines the SmallVector class.
void emitAll(MCStreamer &Streamer)
void clearCacheForCurrentSection(MCStreamer &Streamer)
void emitForCurrentSection(MCStreamer &Streamer)
const MCExpr * addEntry(MCStreamer &Streamer, const MCExpr *Expr, unsigned Size, SMLoc Loc)
const MCExpr * addEntry(const MCExpr *Value, MCContext &Context, unsigned Size, SMLoc Loc)
ConstantPool()=default
void emitEntries(MCStreamer &Streamer)
Context object for machine code objects.
Definition: MCContext.h:76
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:35
Instances of this class represent a uniqued identifier for a section in the current translation unit.
Definition: MCSection.h:39
Streaming machine code generation interface.
Definition: MCStreamer.h:212
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:40
Represents a location in source code.
Definition: SMLoc.h:23
LLVM Value Representation.
Definition: Value.h:74
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
ConstantPoolEntry(MCSymbol *L, const MCExpr *Val, unsigned Sz, SMLoc Loc_)
Definition: ConstantPools.h:32
const MCExpr * Value
Definition: ConstantPools.h:36