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[NVPTX] add support for .debug_loc section #110905

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Merged
merged 2 commits into from
Oct 3, 2024
Merged

[NVPTX] add support for .debug_loc section #110905

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db9e307
[NVPTX] add support for .debug_loc section
willghatch Sep 26, 2024
cfe02c9
adjust if blocks
willghatch Oct 3, 2024
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25 changes: 17 additions & 8 deletions llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -352,8 +352,6 @@ DwarfDebug::DwarfDebug(AsmPrinter *A)
else
UseInlineStrings = DwarfInlinedStrings == Enable;

UseLocSection = !TT.isNVPTX();

// Always emit .debug_aranges for SCE tuning.
UseARangesSection = GenerateARangeSection || tuneForSCE();

Expand Down Expand Up @@ -1324,7 +1322,12 @@ void DwarfDebug::finalizeModuleInfo() {
// ranges for all subprogram DIEs for mach-o.
DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;

if (unsigned NumRanges = TheCU.getRanges().size()) {
if (Asm->TM.getTargetTriple().isNVPTX() && tuneForGDB()) {
// PTX does not support subtracting labels from the code section in the
// debug_loc section. To work around this, the NVPTX backend needs the
// compile unit to have no low_pc in order to have a zero base_address
// when handling debug_loc in cuda-gdb.
Comment on lines +1326 to +1329
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@walter-erquinigo walter-erquinigo Oct 2, 2024

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These if/else blocks read a bit weird. Better collapse them into a single if condition

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@willghatch willghatch Oct 3, 2024

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I've moved the PTX test inside the other block, which is probably easier to read. I don't want to merge the two conditions, exactly, since one is an assignment, and a type-preserving merge would be ugly there.

} else if (unsigned NumRanges = TheCU.getRanges().size()) {
if (NumRanges > 1 && useRangesSection())
// A DW_AT_low_pc attribute may also be specified in combination with
// DW_AT_ranges to specify the default base address for use in
Expand Down Expand Up @@ -1920,10 +1923,6 @@ void DwarfDebug::collectEntityInfo(DwarfCompileUnit &TheCU,
}
}

// Do not emit location lists if .debug_loc secton is disabled.
if (!useLocSection())
continue;

// Handle multiple DBG_VALUE instructions describing one variable.
DebugLocStream::ListBuilder List(DebugLocs, TheCU, *Asm, *RegVar);

Expand Down Expand Up @@ -2841,7 +2840,17 @@ static void emitRangeList(
bool BaseIsSet = false;
for (const auto &P : SectionRanges) {
auto *Base = CUBase;
if (!Base && ShouldUseBaseAddress) {
if ((Asm->TM.getTargetTriple().isNVPTX() && DD.tuneForGDB())) {
// PTX does not support subtracting labels from the code section in the
// debug_loc section. To work around this, the NVPTX backend needs the
// compile unit to have no low_pc in order to have a zero base_address
// when handling debug_loc in cuda-gdb. Additionally, cuda-gdb doesn't
// seem to handle setting a per-variable base to zero. To make cuda-gdb
// happy, just emit labels with no base while having no compile unit
// low_pc.
BaseIsSet = false;
Base = nullptr;
} else if (!Base && ShouldUseBaseAddress) {
const MCSymbol *Begin = P.second.front()->Begin;
const MCSymbol *NewBase = DD.getSectionLabel(&Begin->getSection());
if (!UseDwarf5) {
Expand Down
6 changes: 0 additions & 6 deletions llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
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Expand Up @@ -432,9 +432,6 @@ class DwarfDebug : public DebugHandlerBase {
/// temp symbols inside DWARF sections.
bool UseSectionsAsReferences = false;

///Allow emission of the .debug_loc section.
bool UseLocSection = true;

/// Allow emission of .debug_aranges section
bool UseARangesSection = false;

Expand Down Expand Up @@ -791,9 +788,6 @@ class DwarfDebug : public DebugHandlerBase {
return UseSectionsAsReferences;
}

/// Returns whether .debug_loc section should be emitted.
bool useLocSection() const { return UseLocSection; }

/// Returns whether to generate DWARF v4 type units.
bool generateTypeUnits() const { return GenerateTypeUnits; }

Expand Down
4 changes: 2 additions & 2 deletions llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
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Expand Up @@ -964,8 +964,8 @@ bool NVPTXAsmPrinter::doFinalization(Module &M) {
// Close the last emitted section
if (hasDebugInfo()) {
TS->closeLastSection();
// Emit empty .debug_loc section for better support of the empty files.
OutStreamer->emitRawText("\t.section\t.debug_loc\t{\t}");
// Emit empty .debug_macinfo section for better support of the empty files.
OutStreamer->emitRawText("\t.section\t.debug_macinfo\t{\t}");
}

// Output last DWARF .file directives, if any.
Expand Down
256 changes: 125 additions & 131 deletions llvm/test/DebugInfo/NVPTX/cu-range-hole.ll
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292 changes: 143 additions & 149 deletions llvm/test/DebugInfo/NVPTX/dbg-declare-alloca.ll
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598 changes: 296 additions & 302 deletions llvm/test/DebugInfo/NVPTX/debug-addr-class.ll
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2 changes: 1 addition & 1 deletion llvm/test/DebugInfo/NVPTX/debug-empty.ll
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Expand Up @@ -2,7 +2,7 @@
; RUN: %if ptxas %{ llc < %s -mtriple=nvptx64-nvidia-cuda | %ptxas-verify %}

; CHECK: .target sm_{{[0-9]+$}}
; CHECK: .section .debug_loc { }
; CHECK: .section .debug_macinfo { }
; CHECK-NOT: }

!llvm.dbg.cu = !{!0}
Expand Down
72 changes: 33 additions & 39 deletions llvm/test/DebugInfo/NVPTX/debug-file-loc.ll
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Expand Up @@ -30,49 +30,45 @@ bb:

; CHECK-DAG: .file [[FOO]] "/source/dir{{/|\\\\}}foo.h"
; CHECK-DAG: .file [[BAR]] "/source/dir{{/|\\\\}}bar.cu"
; CHECK: .section .debug_abbrev
; CHECK-NEXT: {
; CHECK-NEXT: .b8 1 // Abbreviation Code
; CHECK-NEXT: .b8 17 // DW_TAG_compile_unit
; CHECK-NEXT: .b8 0 // DW_CHILDREN_no
; CHECK-NEXT: .b8 37 // DW_AT_producer
; CHECK-NEXT: .b8 8 // DW_FORM_string
; CHECK-NEXT: .b8 19 // DW_AT_language
; CHECK-NEXT: .b8 5 // DW_FORM_data2
; CHECK-NEXT: .b8 3 // DW_AT_name
; CHECK-NEXT: .b8 8 // DW_FORM_string
; CHECK-NEXT: .b8 16 // DW_AT_stmt_list
; CHECK-NEXT: .b8 6 // DW_FORM_data4
; CHECK-NEXT: .b8 27 // DW_AT_comp_dir
; CHECK-NEXT: .b8 8 // DW_FORM_string
; CHECK-NEXT: .b8 17 // DW_AT_low_pc
; CHECK-NEXT: .b8 1 // DW_FORM_addr
; CHECK-NEXT: .b8 18 // DW_AT_high_pc
; CHECK-NEXT: .b8 1 // DW_FORM_addr
; CHECK-NEXT: .b8 0 // EOM(1)
; CHECK-NEXT: .b8 0 // EOM(2)
; CHECK-NEXT: .b8 0 // EOM(3)
; CHECK-NEXT: }
; CHECK-NEXT: .section .debug_info
; CHECK-NEXT: {
; CHECK-NEXT: .b32 50 // Length of Unit
; CHECK-NEXT: .b8 2 // DWARF version number
; CHECK: .section .debug_abbrev
; CHECK-NEXT: {
; CHECK-NEXT: .b8 1 // Abbreviation Code
; CHECK-NEXT: .b8 17 // DW_TAG_compile_unit
; CHECK-NEXT: .b8 0 // DW_CHILDREN_no
; CHECK-NEXT: .b8 37 // DW_AT_producer
; CHECK-NEXT: .b8 8 // DW_FORM_string
; CHECK-NEXT: .b8 19 // DW_AT_language
; CHECK-NEXT: .b8 5 // DW_FORM_data2
; CHECK-NEXT: .b8 3 // DW_AT_name
; CHECK-NEXT: .b8 8 // DW_FORM_string
; CHECK-NEXT: .b8 16 // DW_AT_stmt_list
; CHECK-NEXT: .b8 6 // DW_FORM_data4
; CHECK-NEXT: .b8 27 // DW_AT_comp_dir
; CHECK-NEXT: .b8 8 // DW_FORM_string
; CHECK-NEXT: .b8 0 // EOM(1)
; CHECK-NEXT: .b8 0 // EOM(2)
; CHECK-NEXT: .b8 0 // EOM(3)
; CHECK-NEXT: }
; CHECK-NEXT: .section .debug_info
; CHECK-NEXT: {
; CHECK-NEXT: .b32 34 // Length of Unit
; CHECK-NEXT: .b8 2 // DWARF version number
; CHECK-NEXT: .b8 0
; CHECK-NEXT: .b32 .debug_abbrev // Offset Into Abbrev. Section
; CHECK-NEXT: .b8 8 // Address Size (in bytes)
; CHECK-NEXT: .b8 1 // Abbrev [1] 0xb:0x2b DW_TAG_compile_unit
; CHECK-NEXT: .b8 0 // DW_AT_producer
; CHECK-NEXT: .b8 4 // DW_AT_language
; CHECK-NEXT: .b32 .debug_abbrev // Offset Into Abbrev. Section
; CHECK-NEXT: .b8 8 // Address Size (in bytes)
; CHECK-NEXT: .b8 1 // Abbrev [1] 0xb:0x1b DW_TAG_compile_unit
; CHECK-NEXT: .b8 0 // DW_AT_producer
; CHECK-NEXT: .b8 4 // DW_AT_language
; CHECK-NEXT: .b8 0
; CHECK-NEXT: .b8 98 // DW_AT_name
; CHECK-NEXT: .b8 98 // DW_AT_name
; CHECK-NEXT: .b8 97
; CHECK-NEXT: .b8 114
; CHECK-NEXT: .b8 46
; CHECK-NEXT: .b8 99
; CHECK-NEXT: .b8 117
; CHECK-NEXT: .b8 0
; CHECK-NEXT: .b32 .debug_line // DW_AT_stmt_list
; CHECK-NEXT: .b8 47 // DW_AT_comp_dir
; CHECK-NEXT: .b32 .debug_line // DW_AT_stmt_list
; CHECK-NEXT: .b8 47 // DW_AT_comp_dir
; CHECK-NEXT: .b8 115
; CHECK-NEXT: .b8 111
; CHECK-NEXT: .b8 117
Expand All @@ -84,10 +80,8 @@ bb:
; CHECK-NEXT: .b8 105
; CHECK-NEXT: .b8 114
; CHECK-NEXT: .b8 0
; CHECK-NEXT: .b64 $L__func_begin0 // DW_AT_low_pc
; CHECK-NEXT: .b64 $L__func_end1 // DW_AT_high_pc
; CHECK-NEXT: }
; CHECK-NEXT: .section .debug_loc { }
; CHECK-NEXT: }
; CHECK-NEXT: .section .debug_macinfo { }
; CHECK-NOT: debug_

!llvm.dbg.cu = !{!0}
Expand Down
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