Skip to content

Commit

Permalink
fix Issue 14281 - duplicate .debug_info entries for arrays, delegates…
Browse files Browse the repository at this point in the history 
… and aa's

- the duplicates exist because DW_AT_sibling pointers
  are unique for each entry and thus the hashing cache
  doesn't work
- as DW_AT_sibling hardly provides a benefit when
  skipping over a few bytes, it's better to remove it
- also shrinks debug info by a few percent
  • Loading branch information
@MartinNowak
MartinNowak committed Apr 10, 2015
1 parent c392c80 commit 5229aa4
Showing 1 changed file with 8 additions and 68 deletions.
76 changes: 8 additions & 68 deletions src/backend/dwarf.c
View file
Expand Up @@ -1743,7 +1743,6 @@ unsigned dwarf_typidx(type *t)
{
DW_TAG_structure_type,
1, // children
DW_AT_sibling, DW_FORM_ref4,
DW_AT_name, DW_FORM_string,
DW_AT_byte_size, DW_FORM_data1,
0, 0,
Expand Down Expand Up @@ -1789,9 +1788,6 @@ unsigned dwarf_typidx(type *t)
code = dwarf_abbrev_code(abbrevTypeStruct, sizeof(abbrevTypeStruct));
idx = infobuf->size();
infobuf->writeuLEB128(code); // abbreviation code
unsigned siblingoffset = infobuf->size();
unsigned idxsibling = 0;
infobuf->write32(idxsibling); // DW_AT_sibling
infobuf->write("_Array_", 7); // DW_AT_name
if (tybasic(t->Tnext->Tty))
infobuf->writeString(tystring[tybasic(t->Tnext->Tty)]);
Expand All @@ -1818,9 +1814,7 @@ unsigned dwarf_typidx(type *t)
infobuf->writeByte(DW_OP_plus_uconst);
infobuf->writeByte(I64 ? 8 : 4);

infobuf->writeByte(0); // no more siblings
idxsibling = infobuf->size();
*(unsigned *)(infobuf->buf + siblingoffset) = idxsibling;
infobuf->writeByte(0); // no more children
}
#endif
break;
Expand Down Expand Up @@ -1863,9 +1857,6 @@ unsigned dwarf_typidx(type *t)
code = dwarf_abbrev_code(abbrevTypeStruct, sizeof(abbrevTypeStruct));
idx = infobuf->size();
infobuf->writeuLEB128(code); // abbreviation code
unsigned siblingoffset = infobuf->size();
unsigned idxsibling = 0;
infobuf->write32(idxsibling); // DW_AT_sibling
infobuf->writeString("_Delegate"); // DW_AT_name
infobuf->writeByte(tysize(t->Tty)); // DW_AT_byte_size

Expand All @@ -1888,9 +1879,7 @@ unsigned dwarf_typidx(type *t)
infobuf->writeByte(DW_OP_plus_uconst);
infobuf->writeByte(I64 ? 8 : 4);

infobuf->writeByte(0); // no more siblings
idxsibling = infobuf->size();
*(unsigned *)(infobuf->buf + siblingoffset) = idxsibling;
infobuf->writeByte(0); // no more children
}
#endif
break;
Expand Down Expand Up @@ -1932,9 +1921,6 @@ unsigned dwarf_typidx(type *t)
code = dwarf_abbrev_code(abbrevTypeStruct, sizeof(abbrevTypeStruct));
idx = infobuf->size();
infobuf->writeuLEB128(code); // abbreviation code
unsigned siblingoffset = infobuf->size();
unsigned idxsibling = 0;
infobuf->write32(idxsibling); // DW_AT_sibling
infobuf->write("_AArray_", 8); // DW_AT_name
if (tybasic(t->Tkey->Tty))
p = tystring[tybasic(t->Tkey->Tty)];
Expand All @@ -1961,9 +1947,7 @@ unsigned dwarf_typidx(type *t)
infobuf->writeByte(DW_OP_plus_uconst);
infobuf->writeByte(0);

infobuf->writeByte(0); // no more siblings
idxsibling = infobuf->size();
*(unsigned *)(infobuf->buf + siblingoffset) = idxsibling;
infobuf->writeByte(0); // no more children
}
#endif
break;
Expand Down Expand Up @@ -2050,10 +2034,7 @@ unsigned dwarf_typidx(type *t)
Outbuffer abuf; // for abbrev
abuf.writeByte(DW_TAG_subroutine_type);
if (params)
{
abuf.writeByte(1); // children
abuf.writeByte(DW_AT_sibling); abuf.writeByte(DW_FORM_ref4);
}
else
abuf.writeByte(0); // no children
abuf.writeByte(DW_AT_prototyped); abuf.writeByte(DW_FORM_flag);
Expand All @@ -2074,14 +2055,8 @@ unsigned dwarf_typidx(type *t)
paramcode = dwarf_abbrev_code(abuf.buf, abuf.size());
}

unsigned idxsibling = 0;
unsigned siblingoffset;

idx = infobuf->size();
infobuf->writeuLEB128(code);
siblingoffset = infobuf->size();
if (params)
infobuf->write32(idxsibling); // DW_AT_sibling
infobuf->writeByte(1); // DW_AT_prototyped
if (nextidx) // if return type is not void
infobuf->write32(nextidx); // DW_AT_type
Expand All @@ -2098,10 +2073,6 @@ unsigned dwarf_typidx(type *t)
infobuf->write32(paramidx); // DW_AT_type
}
infobuf->writeByte(0); // end parameter list

// This is why the usual typidx caching does not work; this is unique every time
idxsibling = infobuf->size();
*(unsigned *)(infobuf->buf + siblingoffset) = idxsibling;
}

*pidx = idx; // remember it in the functype_table[] cache
Expand All @@ -2113,15 +2084,13 @@ unsigned dwarf_typidx(type *t)
{
DW_TAG_array_type,
1, // child (the subrange type)
DW_AT_sibling, DW_FORM_ref4,
DW_AT_type, DW_FORM_ref4,
0, 0,
};
static unsigned char abbrevTypeArrayVoid[] =
{
DW_TAG_array_type,
1, // child (the subrange type)
DW_AT_sibling, DW_FORM_ref4,
0, 0,
};
static unsigned char abbrevTypeSubrange[] =
Expand All @@ -2143,16 +2112,12 @@ unsigned dwarf_typidx(type *t)
? dwarf_abbrev_code(abbrevTypeSubrange2, sizeof(abbrevTypeSubrange2))
: dwarf_abbrev_code(abbrevTypeSubrange, sizeof(abbrevTypeSubrange));
unsigned idxbase = dwarf_typidx(tssize);
unsigned idxsibling = 0;
unsigned siblingoffset;
nextidx = dwarf_typidx(t->Tnext);
unsigned code1 = nextidx ? dwarf_abbrev_code(abbrevTypeArray, sizeof(abbrevTypeArray))
: dwarf_abbrev_code(abbrevTypeArrayVoid, sizeof(abbrevTypeArrayVoid));
idx = infobuf->size();

infobuf->writeuLEB128(code1); // DW_TAG_array_type
siblingoffset = infobuf->size();
infobuf->write32(idxsibling); // DW_AT_sibling
if (nextidx)
infobuf->write32(nextidx); // DW_AT_type

Expand All @@ -2161,9 +2126,7 @@ unsigned dwarf_typidx(type *t)
if (!(t->Tflags & TFsizeunknown))
infobuf->write32(t->Tdim ? t->Tdim - 1 : 0); // DW_AT_upper_bound

infobuf->writeByte(0); // no more siblings
idxsibling = infobuf->size();
*(unsigned *)(infobuf->buf + siblingoffset) = idxsibling;
infobuf->writeByte(0); // no more children
break;
}

Expand All @@ -2186,7 +2149,6 @@ unsigned dwarf_typidx(type *t)
1, // child (the subrange type)
(DW_AT_GNU_vector & 0x7F) | 0x80, DW_AT_GNU_vector >> 7, DW_FORM_flag,
DW_AT_type, DW_FORM_ref4,
DW_AT_sibling, DW_FORM_ref4,
0, 0,
};
static unsigned char abbrevSubRange[] =
Expand All @@ -2199,26 +2161,20 @@ unsigned dwarf_typidx(type *t)

unsigned code = dwarf_abbrev_code(abbrevTypeArray, sizeof(abbrevTypeArray));
unsigned idxbase = dwarf_typidx(tbase);
unsigned siblingoffset;

idx = infobuf->size();

infobuf->writeuLEB128(code); // DW_TAG_array_type
infobuf->writeByte(1); // DW_AT_GNU_vector
infobuf->write32(idxbase); // DW_AT_type
siblingoffset = infobuf->size();
infobuf->write32(0); // DW_AT_sibling

// vector length stored as subrange type
code = dwarf_abbrev_code(abbrevSubRange, sizeof(abbrevSubRange));
infobuf->writeuLEB128(code); // DW_TAG_subrange_type
unsigned char dim = tysize[tybasic(t->Tty)] / tysize[tybasic(tbase->Tty)];
infobuf->writeByte(dim - 1); // DW_AT_upper_bound


infobuf->writeByte(0); // no more siblings
unsigned idxsibling = infobuf->size();
*(unsigned *)(infobuf->buf + siblingoffset) = idxsibling;

infobuf->writeByte(0); // no more children
break;
}

Expand Down Expand Up @@ -2310,7 +2266,6 @@ unsigned dwarf_typidx(type *t)
abuf.writeByte((st->Sflags & STRunion)
? DW_TAG_union_type : DW_TAG_structure_type);
abuf.writeByte(1); // children
abuf.writeByte(DW_AT_sibling); abuf.writeByte(DW_FORM_ref4);
abuf.writeByte(DW_AT_name); abuf.writeByte(DW_FORM_string);
abuf.writeByte(DW_AT_byte_size);

Expand Down Expand Up @@ -2339,13 +2294,8 @@ unsigned dwarf_typidx(type *t)
abuf.writeByte(0);
membercode = dwarf_abbrev_code(abuf.buf, abuf.size());

unsigned idxsibling = 0;
unsigned siblingoffset;

idx = infobuf->size();
infobuf->writeuLEB128(code);
siblingoffset = infobuf->size();
infobuf->write32(idxsibling); // DW_AT_sibling
infobuf->writeString(s->Sident); // DW_AT_name
if (sz <= 0xFF)
infobuf->writeByte(sz); // DW_AT_byte_size
Expand Down Expand Up @@ -2378,9 +2328,7 @@ unsigned dwarf_typidx(type *t)
}
}

infobuf->writeByte(0); // no more siblings
idxsibling = infobuf->size();
*(unsigned *)(infobuf->buf + siblingoffset) = idxsibling;
infobuf->writeByte(0); // no more children
}
s->Stypidx = idx;
return idx; // no need to cache it
Expand All @@ -2391,7 +2339,6 @@ unsigned dwarf_typidx(type *t)
{
DW_TAG_enumeration_type,
1, // child (the subrange type)
DW_AT_sibling, DW_FORM_ref4,
DW_AT_name, DW_FORM_string,
DW_AT_byte_size, DW_FORM_data1,
0, 0,
Expand Down Expand Up @@ -2451,13 +2398,8 @@ unsigned dwarf_typidx(type *t)
abuf.writeByte(0);
membercode = dwarf_abbrev_code(abuf.buf, abuf.size());

unsigned idxsibling = 0;
unsigned siblingoffset;

idx = infobuf->size();
infobuf->writeuLEB128(code);
siblingoffset = infobuf->size();
infobuf->write32(idxsibling); // DW_AT_sibling
infobuf->writeString(s->Sident); // DW_AT_name
infobuf->writeByte(sz); // DW_AT_byte_size

Expand All @@ -2473,9 +2415,7 @@ unsigned dwarf_typidx(type *t)
infobuf->writesLEB128(value);
}

infobuf->writeByte(0); // no more siblings
idxsibling = infobuf->size();
*(unsigned *)(infobuf->buf + siblingoffset) = idxsibling;
infobuf->writeByte(0); // no more children

s->Stypidx = idx;
return idx; // no need to cache it
Expand Down

0 comments on commit 5229aa4

Please sign in to comment.