blob: aa7e2311d24086dc18d71d539f7d0f3dce9eb159 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
//===-- WebAssemblyWasmObjectWriter.cpp - WebAssembly Wasm Writer ---------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file handles Wasm-specific object emission, converting LLVM's
/// internal fixups into the appropriate relocations.
///
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/WebAssemblyFixupKinds.h"
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "llvm/BinaryFormat/Wasm.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCFixup.h"
#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSectionWasm.h"
#include "llvm/MC/MCSymbolWasm.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/MCWasmObjectWriter.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
namespace {
class WebAssemblyWasmObjectWriter final : public MCWasmObjectTargetWriter {
public:
explicit WebAssemblyWasmObjectWriter(bool Is64Bit, bool IsEmscripten);
private:
unsigned getRelocType(const MCValue &Target,
const MCFixup &Fixup) const override;
};
} // end anonymous namespace
WebAssemblyWasmObjectWriter::WebAssemblyWasmObjectWriter(bool Is64Bit,
bool IsEmscripten)
: MCWasmObjectTargetWriter(Is64Bit, IsEmscripten) {}
static const MCSection *getFixupSection(const MCExpr *Expr) {
if (auto SyExp = dyn_cast<MCSymbolRefExpr>(Expr)) {
if (SyExp->getSymbol().isInSection())
return &SyExp->getSymbol().getSection();
return nullptr;
}
if (auto BinOp = dyn_cast<MCBinaryExpr>(Expr)) {
auto SectionLHS = getFixupSection(BinOp->getLHS());
auto SectionRHS = getFixupSection(BinOp->getRHS());
return SectionLHS == SectionRHS ? nullptr : SectionLHS;
}
if (auto UnOp = dyn_cast<MCUnaryExpr>(Expr))
return getFixupSection(UnOp->getSubExpr());
return nullptr;
}
unsigned WebAssemblyWasmObjectWriter::getRelocType(const MCValue &Target,
const MCFixup &Fixup) const {
const MCSymbolRefExpr *RefA = Target.getSymA();
assert(RefA);
auto& SymA = cast<MCSymbolWasm>(RefA->getSymbol());
MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
switch (Modifier) {
case MCSymbolRefExpr::VK_GOT:
return wasm::R_WASM_GLOBAL_INDEX_LEB;
case MCSymbolRefExpr::VK_WASM_TBREL:
assert(SymA.isFunction());
return wasm::R_WASM_TABLE_INDEX_REL_SLEB;
case MCSymbolRefExpr::VK_WASM_TLSREL:
return wasm::R_WASM_MEMORY_ADDR_TLS_SLEB;
case MCSymbolRefExpr::VK_WASM_MBREL:
assert(SymA.isData());
return is64Bit() ? wasm::R_WASM_MEMORY_ADDR_REL_SLEB64
: wasm::R_WASM_MEMORY_ADDR_REL_SLEB;
case MCSymbolRefExpr::VK_WASM_TYPEINDEX:
return wasm::R_WASM_TYPE_INDEX_LEB;
default:
break;
}
switch (unsigned(Fixup.getKind())) {
case WebAssembly::fixup_sleb128_i32:
if (SymA.isFunction())
return wasm::R_WASM_TABLE_INDEX_SLEB;
return wasm::R_WASM_MEMORY_ADDR_SLEB;
case WebAssembly::fixup_sleb128_i64:
if (SymA.isFunction())
return wasm::R_WASM_TABLE_INDEX_SLEB64;
return wasm::R_WASM_MEMORY_ADDR_SLEB64;
case WebAssembly::fixup_uleb128_i32:
if (SymA.isGlobal())
return wasm::R_WASM_GLOBAL_INDEX_LEB;
if (SymA.isFunction())
return wasm::R_WASM_FUNCTION_INDEX_LEB;
if (SymA.isEvent())
return wasm::R_WASM_EVENT_INDEX_LEB;
if (SymA.isTable())
return wasm::R_WASM_TABLE_NUMBER_LEB;
return wasm::R_WASM_MEMORY_ADDR_LEB;
case WebAssembly::fixup_uleb128_i64:
assert(SymA.isData());
return wasm::R_WASM_MEMORY_ADDR_LEB64;
case FK_Data_4:
if (SymA.isFunction())
return wasm::R_WASM_TABLE_INDEX_I32;
if (SymA.isGlobal())
return wasm::R_WASM_GLOBAL_INDEX_I32;
if (auto Section = static_cast<const MCSectionWasm *>(
getFixupSection(Fixup.getValue()))) {
if (Section->getKind().isText())
return wasm::R_WASM_FUNCTION_OFFSET_I32;
else if (!Section->isWasmData())
return wasm::R_WASM_SECTION_OFFSET_I32;
}
return wasm::R_WASM_MEMORY_ADDR_I32;
case FK_Data_8:
if (SymA.isFunction())
return wasm::R_WASM_TABLE_INDEX_I64;
if (SymA.isGlobal())
llvm_unreachable("unimplemented R_WASM_GLOBAL_INDEX_I64");
if (auto Section = static_cast<const MCSectionWasm *>(
getFixupSection(Fixup.getValue()))) {
if (Section->getKind().isText())
return wasm::R_WASM_FUNCTION_OFFSET_I64;
else if (!Section->isWasmData())
llvm_unreachable("unimplemented R_WASM_SECTION_OFFSET_I64");
}
assert(SymA.isData());
return wasm::R_WASM_MEMORY_ADDR_I64;
default:
llvm_unreachable("unimplemented fixup kind");
}
}
std::unique_ptr<MCObjectTargetWriter>
llvm::createWebAssemblyWasmObjectWriter(bool Is64Bit, bool IsEmscripten) {
return std::make_unique<WebAssemblyWasmObjectWriter>(Is64Bit, IsEmscripten);
}
|
