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[WebAssembly] MC: Use WritePatchableLEB helper function. NFC. 

Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D57477

llvm-svn: 352683
This commit is contained in:
Sam Clegg 2019-01-30 22:47:35 +00:00
parent 0bb9865011
commit 19e8befabb
1 changed files with 30 additions and 33 deletions
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63
llvm/lib/MC/WasmObjectWriter.cpp
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@ -194,6 +194,33 @@ raw_ostream &operator<<(raw_ostream &OS, const WasmRelocationEntry &Rel) {
}
#endif
// Write X as an (unsigned) LEB value at offset Offset in Stream, padded
// to allow patching.
static void WritePatchableLEB(raw_pwrite_stream &Stream, uint32_t X,
uint64_t Offset) {
uint8_t Buffer[5];
unsigned SizeLen = encodeULEB128(X, Buffer, 5);
assert(SizeLen == 5);
Stream.pwrite((char *)Buffer, SizeLen, Offset);
}
// Write X as an signed LEB value at offset Offset in Stream, padded
// to allow patching.
static void WritePatchableSLEB(raw_pwrite_stream &Stream, int32_t X,
uint64_t Offset) {
uint8_t Buffer[5];
unsigned SizeLen = encodeSLEB128(X, Buffer, 5);
assert(SizeLen == 5);
Stream.pwrite((char *)Buffer, SizeLen, Offset);
}
// Write X as a plain integer value at offset Offset in Stream.
static void WriteI32(raw_pwrite_stream &Stream, uint32_t X, uint64_t Offset) {
uint8_t Buffer[4];
support::endian::write32le(Buffer, X);
Stream.pwrite((char *)Buffer, sizeof(Buffer), Offset);
}
class WasmObjectWriter : public MCObjectWriter {
support::endian::Writer W;
@ -345,7 +372,7 @@ void WasmObjectWriter::startSection(SectionBookkeeping &Section,
// The section size. We don't know the size yet, so reserve enough space
// for any 32-bit value; we'll patch it later.
encodeULEB128(UINT32_MAX, W.OS);
encodeULEB128(0, W.OS, 5);
// The position where the section starts, for measuring its size.
Section.ContentsOffset = W.OS.tell();
@ -379,11 +406,8 @@ void WasmObjectWriter::endSection(SectionBookkeeping &Section) {
// Write the final section size to the payload_len field, which follows
// the section id byte.
uint8_t Buffer[16];
unsigned SizeLen = encodeULEB128(Size, Buffer, 5);
assert(SizeLen == 5);
static_cast<raw_pwrite_stream &>(W.OS).pwrite((char *)Buffer, SizeLen,
Section.SizeOffset);
WritePatchableLEB(static_cast<raw_pwrite_stream &>(W.OS), Size,
Section.SizeOffset);
}
// Emit the Wasm header.
@ -532,33 +556,6 @@ void WasmObjectWriter::recordRelocation(MCAssembler &Asm,
}
}
// Write X as an (unsigned) LEB value at offset Offset in Stream, padded
// to allow patching.
static void WritePatchableLEB(raw_pwrite_stream &Stream, uint32_t X,
uint64_t Offset) {
uint8_t Buffer[5];
unsigned SizeLen = encodeULEB128(X, Buffer, 5);
assert(SizeLen == 5);
Stream.pwrite((char *)Buffer, SizeLen, Offset);
}
// Write X as an signed LEB value at offset Offset in Stream, padded
// to allow patching.
static void WritePatchableSLEB(raw_pwrite_stream &Stream, int32_t X,
uint64_t Offset) {
uint8_t Buffer[5];
unsigned SizeLen = encodeSLEB128(X, Buffer, 5);
assert(SizeLen == 5);
Stream.pwrite((char *)Buffer, SizeLen, Offset);
}
// Write X as a plain integer value at offset Offset in Stream.
static void WriteI32(raw_pwrite_stream &Stream, uint32_t X, uint64_t Offset) {
uint8_t Buffer[4];
support::endian::write32le(Buffer, X);
Stream.pwrite((char *)Buffer, sizeof(Buffer), Offset);
}
static const MCSymbolWasm *ResolveSymbol(const MCSymbolWasm &Symbol) {
if (Symbol.isVariable()) {
const MCExpr *Expr = Symbol.getVariableValue();