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(Optional) fix for .debug_line head generation #51

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Merged
luckytyphlosion merged 4 commits into from
Apr 5, 2023
Merged

(Optional) fix for .debug_line head generation #51

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0b2b736
backport fix for .debug_line head generation and add flag for restori…
StanHash Mar 2, 2022
5e572a9
Merge branch 'master' into fix-dwarf-debug-line
StanHash Mar 23, 2023
7b2372d
rename debug_line fix flag and revert behavior
StanHash Apr 4, 2023
0cd8f47
fix comment
StanHash Apr 5, 2023
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41 changes: 39 additions & 2 deletions gcc/dwarf2out.c
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Original file line number Diff line number Diff line change
Expand Up @@ -232,6 +232,10 @@ static unsigned reg_number (rtx);
#define FDE_AFTER_SIZE_LABEL "LSFDE"
#define FDE_END_LABEL "LEFDE"
#define FDE_LENGTH_LABEL "LLFDE"
#define LINE_NUMBER_BEGIN_LABEL "LSLT"
#define LINE_NUMBER_END_LABEL "LELT"
#define LN_PROLOG_AS_LABEL "LASLTP"
#define LN_PROLOG_END_LABEL "LELTP"

/* Definitions of defaults for various types of primitive assembly language
output operations. These may be overridden from within the tm.h file,
Expand Down Expand Up @@ -4301,6 +4305,7 @@ output_aranges ()
static void
output_line_info ()
{
char l1[20], l2[20], p1[20], p2[20];
char line_label[MAX_ARTIFICIAL_LABEL_BYTES];
char prev_line_label[MAX_ARTIFICIAL_LABEL_BYTES];
register unsigned opc;
Expand All @@ -4313,22 +4318,46 @@ output_line_info ()
register unsigned long current_file;
register unsigned long function;

ASM_OUTPUT_DWARF_DATA (asm_out_file, size_of_line_info ());
ASM_GENERATE_INTERNAL_LABEL (l1, LINE_NUMBER_BEGIN_LABEL, 0);
ASM_GENERATE_INTERNAL_LABEL (l2, LINE_NUMBER_END_LABEL, 0);
ASM_GENERATE_INTERNAL_LABEL (p1, LN_PROLOG_AS_LABEL, 0);
ASM_GENERATE_INTERNAL_LABEL (p2, LN_PROLOG_END_LABEL, 0);

if (flag_fixed_debug_line_info)
ASM_OUTPUT_DWARF_DELTA (asm_out_file, l2, l1);
else
ASM_OUTPUT_DWARF_DATA (asm_out_file, size_of_line_info ());

if (flag_debug_asm)
fprintf (asm_out_file, "\t%s Length of Source Line Info.",
ASM_COMMENT_START);

fputc ('\n', asm_out_file);

if (flag_fixed_debug_line_info)
/* start of .debug_line */
ASM_OUTPUT_LABEL(asm_out_file, l1);

ASM_OUTPUT_DWARF_DATA2 (asm_out_file, DWARF_VERSION);
if (flag_debug_asm)
fprintf (asm_out_file, "\t%s DWARF Version", ASM_COMMENT_START);

fputc ('\n', asm_out_file);
ASM_OUTPUT_DWARF_DATA (asm_out_file, size_of_line_prolog ());

if (flag_fixed_debug_line_info)
ASM_OUTPUT_DWARF_DELTA (asm_out_file, p2, p1);
else
ASM_OUTPUT_DWARF_DATA (asm_out_file, size_of_line_prolog ());

if (flag_debug_asm)
fprintf (asm_out_file, "\t%s Prolog Length", ASM_COMMENT_START);

fputc ('\n', asm_out_file);

if (flag_fixed_debug_line_info)
/* start of .debug_line prologue */
ASM_OUTPUT_LABEL(asm_out_file, p1);

ASM_OUTPUT_DWARF_DATA1 (asm_out_file, DWARF_LINE_MIN_INSTR_LENGTH);
if (flag_debug_asm)
fprintf (asm_out_file, "\t%s Minimum Instruction Length",
Expand Down Expand Up @@ -4423,6 +4452,10 @@ output_line_info ()
ASM_OUTPUT_DWARF_DATA1 (asm_out_file, 0);
fputc ('\n', asm_out_file);

if (flag_fixed_debug_line_info)
/* end of .debug_line prologue */
ASM_OUTPUT_LABEL (asm_out_file, p2);

/* Set the address register to the first location in the text section */
ASM_OUTPUT_DWARF_DATA1 (asm_out_file, 0);
if (flag_debug_asm)
Expand Down Expand Up @@ -4738,6 +4771,10 @@ output_line_info ()
fputc ('\n', asm_out_file);
}
}

if (flag_fixed_debug_line_info)
/* end of .debug_line */
ASM_OUTPUT_LABEL (asm_out_file, l2);
}

/* Given a pointer to a BLOCK node return non-zero if (and only if) the node
Expand Down
4 changes: 4 additions & 0 deletions gcc/flags.h
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Original file line number Diff line number Diff line change
Expand Up @@ -450,3 +450,7 @@ extern enum graph_dump_types graph_dump_format;

/* Nonzero if ASM output should use hex instead of decimal. */
extern int flag_hex_asm;

/* Nonzero if generated DWARF debug info should be corrected rather than
match the original (buggy) GCC 2.95.x output. */
extern int flag_fixed_debug_line_info;
5 changes: 5 additions & 0 deletions gcc/toplev.c
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Original file line number Diff line number Diff line change
Expand Up @@ -585,6 +585,9 @@ int flag_instrument_function_entry_exit = 0;
/* Use hex instead of decimal in ASM output. */
int flag_hex_asm = 0;

/* Fix buggy DWARF line info generation. */
int flag_fixed_debug_line_info = 0;

typedef struct
{
char *string;
Expand Down Expand Up @@ -724,6 +727,8 @@ lang_independent_options f_options[] =
"Instrument function entry/exit with profiling calls"},
{"hex-asm", &flag_hex_asm, 1,
"Use hex instead of decimal in assembly output"},
{"fix-debug-line", &flag_fixed_debug_line_info, 1,
"Generate fixed DWARF line info"},
};

#define NUM_ELEM(a) (sizeof (a) / sizeof ((a)[0]))
Expand Down