[llvm] 64c0495 - [MC] Generate .debug_line in the 64-bit DWARF format [2/7]
Igor Kudrin via llvm-commits
llvm-commits at lists.llvm.org
Tue Jun 16 01:51:31 PDT 2020
Author: Igor Kudrin
Date: 2020-06-16T15:50:13+07:00
New Revision: 64c049595b5d04f0f3c3ee8648624663bab19f8c
URL: https://github.com/llvm/llvm-project/commit/64c049595b5d04f0f3c3ee8648624663bab19f8c
DIFF: https://github.com/llvm/llvm-project/commit/64c049595b5d04f0f3c3ee8648624663bab19f8c.diff
LOG: [MC] Generate .debug_line in the 64-bit DWARF format [2/7]
Differential Revision: https://reviews.llvm.org/D81144
Added:
llvm/test/MC/ELF/gen-dwarf64.s
Modified:
llvm/lib/MC/MCDwarf.cpp
Removed:
################################################################################
diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index d75b55c6f8d2..c665f9a9630b 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -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());
diff --git a/llvm/test/MC/ELF/gen-dwarf64.s b/llvm/test/MC/ELF/gen-dwarf64.s
new file mode 100644
index 000000000000..8d456849ee11
--- /dev/null
+++ b/llvm/test/MC/ELF/gen-dwarf64.s
@@ -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]]"
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