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ld: pe: Fix linking against Microsoft import libraries with multiple DLLs

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Initially, since c6c37250e9 (in 1999),
in order to fix linking against Microsoft import libraries, ld did
internally rename members of such libraries. At that point, the
criteria for being considered a Microsoft import library was that
every archive member had the same name (no regard for exactly what
that name was).

This was later amended in 44dbf3639f
(in 2003) to allow for Microsoft import libraries with intermixed
static object files. At this point, the criteria were extended, so
that all members following the first member named *.dll either had
the exact same member name, or be named *.obj. (Curiously, this would
allow members with any name if it precedes the first one named *.dll.)

In practice, Microsoft style import libraries can contain
members for linking against more than one DLL (built by merging
multiple regular import libraries into one).

Instead of trying to do validation of the whole archive before
considering it a Microsoft style import library, relax the criteria
for doing the member renaming: If an archive member is named *.dll
and it contains .idata sections, assume that that member is a
Microsoft import file, and apply the renaming scheme.

This works for imports for any number of DLLs in the same library,
intermixed with other static object files (regardless of their
names), and vastly simplifies the code.

LLVM generates Microsoft style import libraries, and Rust builds
seem to bundle up multiple import libraries together with some
Rust specific static objects. This fixes linking directly against
them with ld.bfd.
This commit is contained in:
Martin Storsjö 2022-08-23 15:48:39 +03:00
parent c95dd24e79
commit 46bbc1c071
2 changed files with 32 additions and 108 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

70
ld/emultempl/pe.em
View File

@ -1649,10 +1649,6 @@ gld${EMULATION_NAME}_after_open (void)
}
{
int is_ms_arch = 0;
bfd *cur_arch = 0;
lang_input_statement_type *is2;
lang_input_statement_type *is3;
/* Careful - this is a shell script. Watch those dollar signs! */
/* Microsoft import libraries have every member named the same,
@ -1668,60 +1664,18 @@ gld${EMULATION_NAME}_after_open (void)
if (is->the_bfd->my_archive)
{
char *pnt;
bfd *arch = is->the_bfd->my_archive;
if (cur_arch != arch)
{
cur_arch = arch;
is_ms_arch = 1;
for (is3 = is;
is3 && is3->the_bfd->my_archive == arch;
is3 = (lang_input_statement_type *) is3->next)
{
/* A MS dynamic import library can also contain static
members, so look for the first element with a .dll
extension, and use that for the remainder of the
comparisons. */
pnt = strrchr (bfd_get_filename (is3->the_bfd), '.');
if (pnt != NULL && fileext_cmp (pnt + 1, "dll") == 0)
break;
}
if (is3 == NULL)
is_ms_arch = 0;
else
{
/* OK, found one. Now look to see if the remaining
(dynamic import) members use the same name. */
for (is2 = is;
is2 && is2->the_bfd->my_archive == arch;
is2 = (lang_input_statement_type *) is2->next)
{
/* Skip static members, ie anything with a .obj
extension. */
pnt = strrchr (bfd_get_filename (is2->the_bfd), '.');
if (pnt != NULL && fileext_cmp (pnt + 1, "obj") == 0)
continue;
if (filename_cmp (bfd_get_filename (is3->the_bfd),
bfd_get_filename (is2->the_bfd)))
{
is_ms_arch = 0;
break;
}
}
}
}
/* This fragment might have come from an .obj file in a Microsoft
import, and not an actual import record. If this is the case,
then leave the filename alone. */
/* Microsoft import libraries may contain archive members for
one or more DLLs, together with static object files.
Inspect all members that are named *.dll - check whether
they contain .idata sections. Do the renaming of all
archive members that seem to be Microsoft style import
objects. */
pnt = strrchr (bfd_get_filename (is->the_bfd), '.');
if (is_ms_arch && pnt != NULL && (fileext_cmp (pnt + 1, "dll") == 0))
if (pnt != NULL && (fileext_cmp (pnt + 1, "dll") == 0))
{
int idata2 = 0, reloc_count=0;
int idata2 = 0, reloc_count = 0, idata = 0;
asection *sec;
char *new_name, seq;
@ -1729,9 +1683,17 @@ gld${EMULATION_NAME}_after_open (void)
{
if (strcmp (sec->name, ".idata\$2") == 0)
idata2 = 1;
if (strncmp (sec->name, ".idata\$", 6) == 0)
idata = 1;
reloc_count += sec->reloc_count;
}
/* An archive member named .dll, but not having any .idata
sections - apparently not a Microsoft import object
after all: Skip renaming it. */
if (!idata)
continue;
if (idata2) /* .idata2 is the TOC */
seq = 'a';
else if (reloc_count > 0) /* thunks */

70
ld/emultempl/pep.em
View File

@ -1613,10 +1613,6 @@ gld${EMULATION_NAME}_after_open (void)
}
{
int is_ms_arch = 0;
bfd *cur_arch = 0;
lang_input_statement_type *is2;
lang_input_statement_type *is3;
/* Careful - this is a shell script. Watch those dollar signs! */
/* Microsoft import libraries have every member named the same,
@ -1632,60 +1628,18 @@ gld${EMULATION_NAME}_after_open (void)
if (is->the_bfd->my_archive)
{
char *pnt;
bfd *arch = is->the_bfd->my_archive;
if (cur_arch != arch)
{
cur_arch = arch;
is_ms_arch = 1;
for (is3 = is;
is3 && is3->the_bfd->my_archive == arch;
is3 = (lang_input_statement_type *) is3->next)
{
/* A MS dynamic import library can also contain static
members, so look for the first element with a .dll
extension, and use that for the remainder of the
comparisons. */
pnt = strrchr (bfd_get_filename (is3->the_bfd), '.');
if (pnt != NULL && fileext_cmp (pnt + 1, "dll") == 0)
break;
}
if (is3 == NULL)
is_ms_arch = 0;
else
{
/* OK, found one. Now look to see if the remaining
(dynamic import) members use the same name. */
for (is2 = is;
is2 && is2->the_bfd->my_archive == arch;
is2 = (lang_input_statement_type *) is2->next)
{
/* Skip static members, ie anything with a .obj
extension. */
pnt = strrchr (bfd_get_filename (is2->the_bfd), '.');
if (pnt != NULL && fileext_cmp (pnt + 1, "obj") == 0)
continue;
if (filename_cmp (bfd_get_filename (is3->the_bfd),
bfd_get_filename (is2->the_bfd)))
{
is_ms_arch = 0;
break;
}
}
}
}
/* This fragment might have come from an .obj file in a Microsoft
import, and not an actual import record. If this is the case,
then leave the filename alone. */
/* Microsoft import libraries may contain archive members for
one or more DLLs, together with static object files.
Inspect all members that are named *.dll - check whether
they contain .idata sections. Do the renaming of all
archive members that seem to be Microsoft style import
objects. */
pnt = strrchr (bfd_get_filename (is->the_bfd), '.');
if (is_ms_arch && pnt != NULL && (fileext_cmp (pnt + 1, "dll") == 0))
if (pnt != NULL && (fileext_cmp (pnt + 1, "dll") == 0))
{
int idata2 = 0, reloc_count=0;
int idata2 = 0, reloc_count = 0, idata = 0;
asection *sec;
char *new_name, seq;
@ -1693,9 +1647,17 @@ gld${EMULATION_NAME}_after_open (void)
{
if (strcmp (sec->name, ".idata\$2") == 0)
idata2 = 1;
if (strncmp (sec->name, ".idata\$", 6) == 0)
idata = 1;
reloc_count += sec->reloc_count;
}
/* An archive member named .dll, but not having any .idata
sections - apparently not a Microsoft import object
after all: Skip renaming it. */
if (!idata)
continue;
if (idata2) /* .idata2 is the TOC */
seq = 'a';
else if (reloc_count > 0) /* thunks */