Skip to content

search for duplicate symbols in machobj #23505

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
rikkimax merged 1 commit into from
Aug 5, 2026
+61 −4
Merged

search for duplicate symbols in machobj #23505

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
59 changes: 57 additions & 2 deletions compiler/src/dmd/backend/machobj.d
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -540,10 +540,32 @@ int mach_numbersyms()

foreach (s; machobj.publicSymbols[])
{
assert(s.Sclass != SC.extern_);
s.Sxtrnnum = n;
n++;
}

/* Search externSymbols[] for duplicates of symbols in publicSymbols([].
* Forward extern symbol to the public symbol, and delete the extern symbol
* from the mach symbol table.
* Not sure localSymbols or comdefs can contain duplicates.
*/
if (machobj.AArch64)
for (int i = 0; i < machobj.externSymbols.length; )

@thewilsonator thewilsonator Aug 1, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

foreach?

@WalterBright WalterBright Aug 1, 2026

Copy link
Copy Markdown
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I didn't use foreach because the removal of an entry could result in reallocating the array, which foreach is not set up to deal with.

@thewilsonator thewilsonator Aug 1, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

In which case a comment explaining that would be good.

{
Symbol* s = machobj.externSymbols[i];
Symbol* sfwd = searchSymbols(machobj.publicSymbols[], s.Sident.ptr);
if (sfwd)
{
assert(sfwd.Sclass != SC.extern_);
s.Sforward = sfwd;
machobj.externSymbols.remove(i); // remove s
//printf("extern %p %s forwarded to %p %s\n", s, s.Sident.ptr, sfwd, sfwd.Sident.ptr);
continue;
}
++i;
}

foreach (s; machobj.externSymbols[])
{
s.Sxtrnnum = n;
Expand Down Expand Up @@ -838,7 +860,7 @@ void MachObj_term(const(char)[] objfilename)
}
}

if (!machobj.AArch64)
// if (!machobj.AArch64)
foreach (i; 0 .. table.length)
table[i] = cast(int)i;

Expand Down Expand Up @@ -1282,6 +1304,7 @@ static if (1)
rel.r_type = X86_64_RELOC_SUBTRACTOR;
rel.r_address = cast(int)r.offset;
rel.r_symbolnum = r.funcsym.Sxtrnnum;
assert(rel.r_symbolnum);
rel.r_pcrel = 0;
rel.r_length = 3;
rel.r_extern = 1;
Expand All @@ -1291,6 +1314,7 @@ static if (1)

rel.r_type = X86_64_RELOC_UNSIGNED;
rel.r_symbolnum = s.Sxtrnnum;
assert(rel.r_symbolnum);
machobj.fobjbuf.write(&rel, rel.sizeof);
foffset += rel.sizeof;
++nreloc;
Expand Down Expand Up @@ -1360,6 +1384,14 @@ static if (1)

rel.r_address = cast(int)r.offset;
rel.r_symbolnum = s.Sxtrnnum;
if (machobj.AArch64 && !rel.r_symbolnum)
{
printf("symbol %p '%s'\n ", s, s.Sident.ptr);
printf(" Sclass = SC.%s ", class_str(s.Sclass));
printf(" Sxtrnnum = %d",cast(int)s.Sxtrnnum);
printf(" Sfl = %s\n", fl_str(cast(FL) s.Sfl));
}
assert(rel.r_symbolnum);
rel.r_pcrel = 1;
rel.r_length = 2;
rel.r_extern = 1;
Expand All @@ -1372,6 +1404,7 @@ static if (1)
{
rel.r_address = cast(int)r.offset;
rel.r_symbolnum = table[s.Sseg];
assert(rel.r_symbolnum);
rel.r_pcrel = 1;
rel.r_length = 2;
rel.r_extern = 0;
Expand Down Expand Up @@ -1399,6 +1432,7 @@ static if (1)
{
rel.r_address = cast(int)r.offset;
rel.r_symbolnum = s.Sxtrnnum;
assert(rel.r_symbolnum);
rel.r_pcrel = 0;
rel.r_length = 2;
rel.r_extern = 1;
Expand All @@ -1417,6 +1451,7 @@ static if (1)
{
rel.r_address = cast(int)r.offset;
rel.r_symbolnum = table[s.Sseg];
assert(rel.r_symbolnum);
rel.r_pcrel = 0;
rel.r_length = 2;
rel.r_extern = 0;
Expand Down Expand Up @@ -1526,6 +1561,7 @@ static if (1)
//printf("r.rtype: %d r.targseg: %d r.offset: x%llx\n", r.rtype, r.targseg, cast(long)r.offset);
rel.r_address = cast(int)r.offset;
rel.r_symbolnum = table[r.targseg];
assert(rel.r_symbolnum);
rel.r_pcrel = (r.rtype == REL.address) ? 0 : 1;
rel.r_length = 2;
rel.r_extern = 0;
Expand Down Expand Up @@ -1812,6 +1848,13 @@ static if (1)
machobj.fobjbuf.position(foffset, 0);

mem_free(table.ptr);

/* Set Sxtrnnum to zero for symbols so we know they are not in the
* object file's symbol table.
*/
if (machobj.AArch64)
foreach (s; machobj.externSymbols[])
s.Sxtrnnum = 0;
}

/*****************************
Expand Down Expand Up @@ -2294,7 +2337,6 @@ int MachObj_getsegment(const(char)* sectname, const(char)* segname,
pseg.SDlinnum_data.reset();

//printf("SegData.length = %zd, seg: %d relocations: %zd\n", SegData.length, seg, pseg.relocations.length);

return seg;
}

Expand Down Expand Up @@ -2376,6 +2418,7 @@ int MachObj_thread_vars(ref Symbol s, out targ_size_t offset, bool bss)
{
//printf("MachObj_thread_vars(s)\n");
//symbol_print(s);

/* create _ident$tlv$init Symbol si
*/
Symbol* si;
Expand Down Expand Up @@ -2681,6 +2724,15 @@ void MachObj_pubdef(int seg, Symbol* s, targ_size_t offset)

s.Soffset = offset;
s.Sseg = seg;
static if (0)
if (strcmp(s.Sident.ptr, "_D3std11parallelism8TaskPool7__ClassZ") == 0)
{
fprintf(stdout, "pubdef symbol %p '%s'\n ", s, s.Sident.ptr);
fprintf(stdout, " Sclass = SC.%s ", class_str(s.Sclass));
fprintf(stdout, " Ssymnum = %d",cast(int)s.Ssymnum);
fprintf(stdout, " Sxtrnnum = %d",cast(int)s.Sxtrnnum);
fprintf(stdout, " Sfl = %s\n\n", fl_str(cast(FL) s.Sfl));
}
switch (s.Sclass)
{
case SC.global:
Expand Down Expand Up @@ -2949,6 +3001,9 @@ void MachObj_addrel(int seg, targ_size_t offset, Symbol* targsym,
rel.val = cast(short)val;

seg_data* pseg = SegData[seg];
if (targsym && targsym.Sxtrnnum == 0)
MachObj_external(targsym);

pseg.relocations.push(rel);
}

Expand Down
6 changes: 4 additions & 2 deletions compiler/src/dmd/glue/toobj.d
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -927,8 +927,9 @@ void toObjFile(Dsymbol ds, bool multiobj)
*/
static void tlsToDt(VarDeclaration vd, Symbol* s, uint sz, ref DtBuilder dtb, bool isCfile)
{
// AArch64?
assert(config.objfmt == OBJ_MACH && target.isX86_64 && (s.Stype.Tty & mTYLINK) == mTYthread);
assert(config.objfmt == OBJ_MACH &&
(target.isX86_64 || target.isAArch64) &&
(s.Stype.Tty & mTYLINK) == mTYthread);

Symbol* tlvInit = createTLVDataSymbol(vd, s);
auto tlvInitDtb = DtBuilder(0);
Expand All @@ -944,6 +945,7 @@ void toObjFile(Dsymbol ds, bool multiobj)
outdata(tlvInit);

tlvInit.Sclass = SC.extern_;
//tlvInit.Sxtrnnum = 0; // not sure about this

Symbol* tlvBootstrap = objmod.tlv_bootstrap();
dtb.xoff(tlvBootstrap, 0, TYnptr);
Expand Down
Loading