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[MC] Generate .debug_line in the 64-bit DWARF format [2/7] 

Differential Revision: https://reviews.llvm.org/D81144
This commit is contained in:
Igor Kudrin 2020-06-03 16:48:37 +07:00
parent a8ec9de406
commit 64c049595b
2 changed files with 45 additions and 10 deletions
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31
llvm/lib/MC/MCDwarf.cpp
View File

@ -332,7 +332,8 @@ void MCDwarfLineStr::emitSection(MCStreamer *MCOS) {
}
void MCDwarfLineStr::emitRef(MCStreamer *MCOS, StringRef Path) {
int RefSize = 4; // FIXME: Support DWARF-64
int RefSize =
dwarf::getDwarfOffsetByteSize(MCOS->getContext().getDwarfFormat());
size_t Offset = LineStrings.add(Path);
if (UseRelocs) {
MCContext &Ctx = MCOS->getContext();
@ -472,10 +473,20 @@ MCDwarfLineTableHeader::Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
// Create a symbol for the end of the section (to be set when we get there).
MCSymbol *LineEndSym = context.createTempSymbol();
// The first 4 bytes is the total length of the information for this
// compilation unit (not including these 4 bytes for the length).
emitAbsValue(
*MCOS, MakeStartMinusEndExpr(context, *LineStartSym, *LineEndSym, 4), 4);
unsigned UnitLengthBytes =
dwarf::getUnitLengthFieldByteSize(context.getDwarfFormat());
unsigned OffsetSize = dwarf::getDwarfOffsetByteSize(context.getDwarfFormat());
if (context.getDwarfFormat() == dwarf::DWARF64)
// Emit DWARF64 mark.
MCOS->emitInt32(dwarf::DW_LENGTH_DWARF64);
// The length field does not include itself and, in case of the 64-bit DWARF
// format, the DWARF64 mark.
emitAbsValue(*MCOS,
MakeStartMinusEndExpr(context, *LineStartSym, *LineEndSym,
UnitLengthBytes),
OffsetSize);
// Next 2 bytes is the Version.
unsigned LineTableVersion = context.getDwarfVersion();
@ -483,7 +494,7 @@ MCDwarfLineTableHeader::Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
// Keep track of the bytes between the very start and where the header length
// comes out.
unsigned PreHeaderLengthBytes = 4 + 2;
unsigned PreHeaderLengthBytes = UnitLengthBytes + 2;
// In v5, we get address info next.
if (LineTableVersion >= 5) {
@ -495,12 +506,12 @@ MCDwarfLineTableHeader::Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
// Create a symbol for the end of the prologue (to be set when we get there).
MCSymbol *ProEndSym = context.createTempSymbol(); // Lprologue_end
// Length of the prologue, is the next 4 bytes. This is actually the length
// from after the length word, to the end of the prologue.
// Length of the prologue, is the next 4 bytes (8 bytes for DWARF64). This is
// actually the length from after the length word, to the end of the prologue.
emitAbsValue(*MCOS,
MakeStartMinusEndExpr(context, *LineStartSym, *ProEndSym,
(PreHeaderLengthBytes + 4)),
4);
(PreHeaderLengthBytes + OffsetSize)),
OffsetSize);
// Parameters of the state machine, are next.
MCOS->emitInt8(context.getAsmInfo()->getMinInstAlignment());

24
llvm/test/MC/ELF/gen-dwarf64.s Normal file
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@ -0,0 +1,24 @@
## This checks that llvm-mc is able to produce 64-bit debug info.
# RUN: llvm-mc -g -dwarf-version 5 -dwarf64 -triple x86_64 %s -filetype=obj -o %t5.o
# RUN: llvm-readobj -r %t5.o | FileCheck --check-prefixes=REL,REL5 %s
# RUN: llvm-dwarfdump -v %t5.o | FileCheck --check-prefixes=DUMP,DUMP5 %s
## The references to other debug info sections are 64-bit, as required for DWARF64.
# REL5: Section ({{[0-9]+}}) .rela.debug_line {
# REL5-NEXT: R_X86_64_64 .debug_line_str 0x0
# REL5-NEXT: R_X86_64_64 .debug_line_str 0x
# DUMP: .debug_line contents:
# DUMP-NEXT: debug_line[0x00000000]
# DUMP-NEXT: Line table prologue:
# DUMP-NEXT: total_length:
# DUMP-NEXT: format: DWARF64
# DUMP5: include_directories[ 0] = .debug_line_str[0x0000000000000000] = "[[DIR:.+]]"
# DUMP5-NEXT: file_names[ 0]:
# DUMP5-NEXT: name: .debug_line_str[0x00000000[[FILEOFF:[[:xdigit:]]{8}]]] = "[[FILE:.+]]"
# DUMP5-NEXT: dir_index: 0
# DUMP5: .debug_line_str contents:
# DUMP5-NEXT: 0x00000000: "[[DIR]]"
# DUMP5-NEXT: 0x[[FILEOFF]]: "[[FILE]]"