1//===- ConstantPools.cpp - ConstantPool class -----------------------------===//
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 implements the ConstantPool and AssemblerConstantPools classes.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/MC/ConstantPools.h"
14#include "llvm/MC/MCContext.h"
15#include "llvm/MC/MCDirectives.h"
16#include "llvm/MC/MCExpr.h"
17#include "llvm/MC/MCStreamer.h"
18#include "llvm/Support/Casting.h"
19
20using namespace llvm;
21
22//
23// ConstantPool implementation
24//
25// Emit the contents of the constant pool using the provided streamer.
26void ConstantPool::emitEntries(MCStreamer &Streamer) {
27 if (Entries.empty())
28 return;
29 Streamer.emitDataRegion(Kind: MCDR_DataRegion);
30 for (const ConstantPoolEntry &Entry : Entries) {
31 Streamer.emitValueToAlignment(Alignment: Align(Entry.Size)); // align naturally
32 Streamer.emitLabel(Symbol: Entry.Label);
33 Streamer.emitValue(Value: Entry.Value, Size: Entry.Size, Loc: Entry.Loc);
34 }
35 Streamer.emitDataRegion(Kind: MCDR_DataRegionEnd);
36 Entries.clear();
37}
38
39const MCExpr *ConstantPool::addEntry(const MCExpr *Value, MCContext &Context,
40 unsigned Size, SMLoc Loc) {
41 const MCConstantExpr *C = dyn_cast<MCConstantExpr>(Val: Value);
42 const MCSymbolRefExpr *S = dyn_cast<MCSymbolRefExpr>(Val: Value);
43
44 // Check if there is existing entry for the same constant. If so, reuse it.
45 if (C) {
46 auto CItr = CachedConstantEntries.find(x: std::make_pair(x: C->getValue(), y&: Size));
47 if (CItr != CachedConstantEntries.end())
48 return CItr->second;
49 }
50
51 // Check if there is existing entry for the same symbol. If so, reuse it.
52 if (S) {
53 auto SItr =
54 CachedSymbolEntries.find(Val: std::make_pair(x: &(S->getSymbol()), y&: Size));
55 if (SItr != CachedSymbolEntries.end())
56 return SItr->second;
57 }
58
59 MCSymbol *CPEntryLabel = Context.createTempSymbol();
60
61 Entries.push_back(Elt: ConstantPoolEntry(CPEntryLabel, Value, Size, Loc));
62 const auto SymRef = MCSymbolRefExpr::create(Symbol: CPEntryLabel, Ctx&: Context, Loc);
63 if (C)
64 CachedConstantEntries[std::make_pair(x: C->getValue(), y&: Size)] = SymRef;
65 if (S)
66 CachedSymbolEntries[std::make_pair(x: &(S->getSymbol()), y&: Size)] = SymRef;
67 return SymRef;
68}
69
70bool ConstantPool::empty() { return Entries.empty(); }
71
72void ConstantPool::clearCache() {
73 CachedConstantEntries.clear();
74 CachedSymbolEntries.clear();
75}
76
77//
78// AssemblerConstantPools implementation
79//
80ConstantPool *AssemblerConstantPools::getConstantPool(MCSection *Section) {
81 ConstantPoolMapTy::iterator CP = ConstantPools.find(Key: Section);
82 if (CP == ConstantPools.end())
83 return nullptr;
84
85 return &CP->second;
86}
87
88ConstantPool &
89AssemblerConstantPools::getOrCreateConstantPool(MCSection *Section) {
90 return ConstantPools[Section];
91}
92
93static void emitConstantPool(MCStreamer &Streamer, MCSection *Section,
94 ConstantPool &CP) {
95 if (!CP.empty()) {
96 Streamer.switchSection(Section);
97 CP.emitEntries(Streamer);
98 }
99}
100
101void AssemblerConstantPools::emitAll(MCStreamer &Streamer) {
102 // Dump contents of assembler constant pools.
103 for (auto &CPI : ConstantPools) {
104 MCSection *Section = CPI.first;
105 ConstantPool &CP = CPI.second;
106
107 emitConstantPool(Streamer, Section, CP);
108 }
109}
110
111void AssemblerConstantPools::emitForCurrentSection(MCStreamer &Streamer) {
112 MCSection *Section = Streamer.getCurrentSectionOnly();
113 if (ConstantPool *CP = getConstantPool(Section))
114 emitConstantPool(Streamer, Section, CP&: *CP);
115}
116
117void AssemblerConstantPools::clearCacheForCurrentSection(MCStreamer &Streamer) {
118 MCSection *Section = Streamer.getCurrentSectionOnly();
119 if (ConstantPool *CP = getConstantPool(Section))
120 CP->clearCache();
121}
122
123const MCExpr *AssemblerConstantPools::addEntry(MCStreamer &Streamer,
124 const MCExpr *Expr,
125 unsigned Size, SMLoc Loc) {
126 MCSection *Section = Streamer.getCurrentSectionOnly();
127 return getOrCreateConstantPool(Section).addEntry(Value: Expr, Context&: Streamer.getContext(),
128 Size, Loc);
129}
130