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ld: dwarf emit filenames in debug_line header instead of as extended opcodes.

Makes it possible for older tools like objdump to find the filenames,
fixes  objdump -d -l --start-address=0x400c00 --stop-address=0x400c36 6.out
fixes #1950

R=rsc
CC=golang-dev
https://golang.org/cl/4609043
This commit is contained in:
Luuk van Dijk 2011-06-13 16:56:43 +02:00
parent b96c3477f8
commit d164b6081d

View File

@ -1804,7 +1804,7 @@ mkvarname(char* name, int da)
// flush previous compilation unit.
static void
flushunit(DWDie *dwinfo, vlong pc, vlong unitstart)
flushunit(DWDie *dwinfo, vlong pc, vlong unitstart, int32 header_length)
{
vlong here;
@ -1820,7 +1820,9 @@ flushunit(DWDie *dwinfo, vlong pc, vlong unitstart)
here = cpos();
seek(cout, unitstart, 0);
LPUT(here - unitstart - sizeof(int32));
LPUT(here - unitstart - sizeof(int32)); // unit_length
WPUT(3); // dwarf version
LPUT(header_length); // header lenght starting here
cflush();
seek(cout, here, 0);
}
@ -1832,7 +1834,7 @@ writelines(void)
Prog *q;
Sym *s;
Auto *a;
vlong unitstart, offs;
vlong unitstart, headerend, offs;
vlong pc, epc, lc, llc, lline;
int currfile;
int i, lang, da, dt;
@ -1842,6 +1844,7 @@ writelines(void)
char *n, *nn;
unitstart = -1;
headerend = -1;
pc = 0;
epc = 0;
lc = 1;
@ -1859,7 +1862,7 @@ writelines(void)
// we're entering a new compilation unit
if (inithist(s->autom)) {
flushunit(dwinfo, epc, unitstart);
flushunit(dwinfo, epc, unitstart, headerend - unitstart - 10);
unitstart = cpos();
if(debug['v'] > 1) {
@ -1880,10 +1883,10 @@ writelines(void)
// Write .debug_line Line Number Program Header (sec 6.2.4)
// Fields marked with (*) must be changed for 64-bit dwarf
LPUT(0); // unit_length (*), will be filled in later.
LPUT(0); // unit_length (*), will be filled in by flushunit.
WPUT(3); // dwarf version (appendix F)
LPUT(11); // header_length (*), starting here.
LPUT(0); // header_length (*), filled in by flushunit.
// cpos == unitstart + 4 + 2 + 4
cput(1); // minimum_instruction_length
cput(1); // default_is_stmt
cput(LINE_BASE); // line_base
@ -1894,17 +1897,15 @@ writelines(void)
cput(1); // standard_opcode_lengths[3]
cput(1); // standard_opcode_lengths[4]
cput(0); // include_directories (empty)
cput(0); // file_names (empty) (emitted by DW_LNE's below)
// header_length ends here.
for (i=1; i < histfilesize; i++) {
cput(0); // start extended opcode
uleb128put(1 + strlen(histfile[i]) + 4);
cput(DW_LNE_define_file);
strnput(histfile[i], strlen(histfile[i]) + 4);
// 4 zeros: the string termination + 3 fields.
}
cput(0); // terminate file_names.
headerend = cpos();
pc = s->text->pc;
epc = pc;
currfile = 1;
@ -2009,7 +2010,7 @@ writelines(void)
dwfunc->hash = nil;
}
flushunit(dwinfo, epc, unitstart);
flushunit(dwinfo, epc, unitstart, headerend - unitstart - 10);
linesize = cpos() - lineo;
}