[PATCH 1/5] Don't claim a fat IR object if no IR object should be claimed
H.J. Lu
hjl.tools@gmail.com
Wed Oct 21 11:35:07 GMT 2020
When the linker sees an input object containing nothing but IR during
rescan, it should ignore it (LTO phase is over). But if the input object
is a fat IR object, which has non-IR code as well, it should be used to
resolve references as if it did not contain any IR at all. This patch
adds lto_type to bfd and linker avoids claiming a fat IR object if no IR
object should be claimed.
bfd/
PR ld/23935
* bfd.c (bfd_lto_object_type): New.
(bfd): Add lto_type.
* format.c: Include "libiberty.h" if BFD_SUPPORTS_PLUGINS is
defined.
(bfd_set_lto_type): New function.
(bfd_check_format_matches): Call bfd_set_lto_type.
* bfd-in2.h: Regenerated.
ld/
PR ld/23935
* ldmain.c (add_archive_element): Don't claim a fat IR object if
no IR object should be claimed.
* testsuite/ld-plugin/lto.exp (pr20103): Adjust fat IR test.
Add PR ld/23935 test.
* testsuite/ld-plugin/pr23935a.c: New file.
* testsuite/ld-plugin/pr23935b.c: Likewise.
---
bfd/bfd-in2.h | 12 ++++-
bfd/bfd.c | 11 +++++
bfd/format.c | 77 ++++++++++++++++++++++++++++++-
ld/ldmain.c | 4 +-
ld/testsuite/ld-plugin/lto.exp | 35 +++++++++++++-
ld/testsuite/ld-plugin/pr23935a.c | 2 +
ld/testsuite/ld-plugin/pr23935b.c | 2 +
7 files changed, 138 insertions(+), 5 deletions(-)
create mode 100644 ld/testsuite/ld-plugin/pr23935a.c
create mode 100644 ld/testsuite/ld-plugin/pr23935b.c
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 935ba535b54..1382fa9a77c 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -1954,7 +1954,6 @@ enum bfd_architecture
#define bfd_mach_ck803 5
#define bfd_mach_ck807 6
#define bfd_mach_ck810 7
-#define bfd_mach_ck860 8
bfd_arch_last
};
@@ -6495,6 +6494,14 @@ struct bfd_build_id
bfd_byte data[1];
};
+enum bfd_lto_object_type
+ {
+ lto_non_object,
+ lto_non_ir_object,
+ lto_ir_object,
+ lto_fat_ir_object
+ };
+
struct bfd
{
/* The filename the application opened the BFD with. */
@@ -6687,6 +6694,9 @@ struct bfd
that BFD is not prepared to handle for objcopy/strip. */
unsigned int read_only : 1;
+ /* LTO object type. */
+ ENUM_BITFIELD (bfd_lto_object_type) lto_type : 2;
+
/* Set to dummy BFD created when claimed by a compiler plug-in
library. */
bfd *plugin_dummy_bfd;
diff --git a/bfd/bfd.c b/bfd/bfd.c
index 449bcc6cefb..ea965db6134 100644
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@@ -57,6 +57,14 @@ CODE_FRAGMENT
. bfd_byte data[1];
. };
.
+.enum bfd_lto_object_type
+. {
+. lto_non_object,
+. lto_non_ir_object,
+. lto_ir_object,
+. lto_fat_ir_object
+. };
+.
.struct bfd
.{
. {* The filename the application opened the BFD with. *}
@@ -249,6 +257,9 @@ CODE_FRAGMENT
. that BFD is not prepared to handle for objcopy/strip. *}
. unsigned int read_only : 1;
.
+. {* LTO object type. *}
+. ENUM_BITFIELD (bfd_lto_object_type) lto_type : 2;
+.
. {* Set to dummy BFD created when claimed by a compiler plug-in
. library. *}
. bfd *plugin_dummy_bfd;
diff --git a/bfd/format.c b/bfd/format.c
index e9212bc6f24..23debf7be1c 100644
--- a/bfd/format.c
+++ b/bfd/format.c
@@ -46,6 +46,9 @@ SUBSECTION
#include "sysdep.h"
#include "bfd.h"
#include "libbfd.h"
+#if BFD_SUPPORTS_PLUGINS
+#include "libiberty.h"
+#endif
/* IMPORT from targets.c. */
extern const size_t _bfd_target_vector_entries;
@@ -201,6 +204,73 @@ bfd_preserve_finish (bfd *abfd ATTRIBUTE_UNUSED, struct bfd_preserve *preserve)
preserve->marker = NULL;
}
+/* Set lto_type in ABFD. */
+
+static void
+bfd_set_lto_type (bfd *abfd ATTRIBUTE_UNUSED)
+{
+#if BFD_SUPPORTS_PLUGINS
+ if (abfd->format == bfd_object
+ && abfd->lto_type == lto_non_object
+ && (abfd->flags & (DYNAMIC | EXEC_P)) == 0)
+ {
+ asection *sec;
+ enum bfd_lto_object_type type = lto_non_ir_object;
+ for (sec = abfd->sections; sec != NULL; sec = sec->next)
+ {
+ if (strncmp (sec->name, ".gnu.lto_", 9) == 0)
+ {
+ type = lto_ir_object;
+ break;
+ }
+ }
+
+ /* FIXME: Check if it is a fat IR object. */
+ if (type == lto_ir_object)
+ {
+ long symsize;
+
+ /* Get symbol table size. */
+ symsize = bfd_get_symtab_upper_bound (abfd);
+ if (symsize > 0)
+ {
+ asymbol **sympp;
+ long symcount;
+
+ /* Read in the symbol table. */
+ sympp = (asymbol **) xmalloc (symsize);
+ symcount = bfd_canonicalize_symtab (abfd, sympp);
+ if (symcount > 0)
+ {
+ long count;
+ const char *name;
+ bfd_boolean thin_ir_object = FALSE;
+
+ for (count = 0; count < symcount; count++)
+ {
+ name = sympp[count]->name;
+ if (name[0] == '_'
+ && name[1] == '_'
+ && strcmp (name + (name[2] == '_'),
+ "__gnu_lto_slim") == 0)
+ {
+ thin_ir_object = TRUE;
+ break;
+ }
+ }
+
+ if (!thin_ir_object)
+ type = lto_fat_ir_object;
+ }
+ free (sympp);
+ }
+ }
+
+ abfd->lto_type = type;
+ }
+#endif
+}
+
/*
FUNCTION
bfd_check_format_matches
@@ -248,7 +318,10 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
}
if (abfd->format != bfd_unknown)
- return abfd->format == format;
+ {
+ bfd_set_lto_type (abfd);
+ return abfd->format == format;
+ }
if (matching != NULL || *bfd_associated_vector != NULL)
{
@@ -505,6 +578,8 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
bfd_preserve_finish (abfd, &preserve_match);
bfd_preserve_finish (abfd, &preserve);
+ bfd_set_lto_type (abfd);
+
/* File position has moved, BTW. */
return TRUE;
}
diff --git a/ld/ldmain.c b/ld/ldmain.c
index cdb4fe58d91..d10f382718f 100644
--- a/ld/ldmain.c
+++ b/ld/ldmain.c
@@ -877,7 +877,9 @@ add_archive_element (struct bfd_link_info *info,
BFD, but we still want to output the original BFD filename. */
orig_input = *input;
#if BFD_SUPPORTS_PLUGINS
- if (link_info.lto_plugin_active)
+ /* Don't claim a fat IR object if no IR object should be claimed. */
+ if (link_info.lto_plugin_active
+ && (!no_more_claiming || abfd->lto_type != lto_fat_ir_object))
{
/* We must offer this archive member to the plugins to claim. */
plugin_maybe_claim (input);
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index abb712575f4..ca6a2b0fce5 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -793,10 +793,20 @@ proc pr20103 {cflags libs} {
set testname "PR ld/20103 ($cflags $libs)"
set exec_output [run_host_cmd "$CC" "$cflags $libs"]
+ # NB: Starting from GCC 4.9, -flto is optional for final link.
+ if { [ regexp "fatpr20103" "$libs" ] \
+ && ([regexp " -flto" "$cflags"] \
+ || [at_least_gcc_version 4 9]) } {
+ set result1good "fail"
+ set result1bad "pass"
+ } {
+ set result1good "pass"
+ set result1bad "fail"
+ }
if { [ regexp "undefined reference to `\\.?dead'" $exec_output ] } {
- pass "$testname (1)"
+ $result1good "$testname (1)"
} {
- fail "$testname (1)"
+ $result1bad "$testname (1)"
}
if { [ regexp "plugin needed to handle lto object" $exec_output ] } {
fail "$testname (2)"
@@ -855,6 +865,27 @@ if { [check_lto_fat_available] } {
"-O2" \
{dummy.c} {} "pr20103c" \
] \
+ [list "Build fatpr23935.a" \
+ "$plug_opt" \
+ "-flto -fno-builtin -ffat-lto-objects" \
+ {pr23935a.c} \
+ "" \
+ "fatpr23935.a" \
+ ] \
+ [list "Build pr23935b.o" \
+ "$plug_opt" \
+ "-flto -fno-fat-lto-objects" \
+ {pr23935b.c} \
+ ] \
+ [list \
+ "Build pr23935" \
+ "-static -flto -Wl,-emain -nostdlib tmpdir/pr23935b.o \
+ tmpdir/fatpr23935.a" \
+ "-flto -fno-fat-lto-objects" \
+ {dummy.c} \
+ "" \
+ "pr23935" \
+ ] \
]
pr20103 "-O2 -flto" "tmpdir/thinpr20103a.a tmpdir/thinpr20103b.a tmpdir/thinpr20103c.a"
pr20103 "-O2 -flto" "tmpdir/fatpr20103a.a tmpdir/fatpr20103b.a tmpdir/fatpr20103c.a"
diff --git a/ld/testsuite/ld-plugin/pr23935a.c b/ld/testsuite/ld-plugin/pr23935a.c
new file mode 100644
index 00000000000..8c731977f41
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr23935a.c
@@ -0,0 +1,2 @@
+#include <stdio.h>
+int puts(const char *s) { return 0; }
diff --git a/ld/testsuite/ld-plugin/pr23935b.c b/ld/testsuite/ld-plugin/pr23935b.c
new file mode 100644
index 00000000000..58ae07e8698
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr23935b.c
@@ -0,0 +1,2 @@
+#include <stdio.h>
+int main() { printf("hi\n"); return 0; }
--
2.26.2
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