From: "H.J. Lu" <hjl.tools@gmail.com>
To: binutils@sourceware.org
Subject: RFC [PATCH 2/2] Use ld_plugin_symbol_type and ld_plugin_symbol_section_flags
Date: Wed, 18 Mar 2020 05:06:38 -0700 [thread overview]
Message-ID: <20200318120638.178388-3-hjl.tools@gmail.com> (raw)
In-Reply-To: <20200318120638.178388-1-hjl.tools@gmail.com>
Since LTO plugin may generate more than one ltrans.o file from one input
IR object as LTO wrapper ignores -flto-partition=none:
lto-wrapper.c:608:
604 /* Drop arguments that we want to take from the link line. */
605 case OPT_flto_:
606 case OPT_flto:
607 case OPT_flto_partition_:
608 continue;
the LTO wrapper approach is not only slow but also unreliable. There is
a proposal to extend The LTO plugin API to add LDPT_ADD_SYMBOLS_V2 with
symbol type and section flags:
https://gcc.gnu.org/pipermail/gcc-patches/2020-March/542187.html
We can use the new LTO plugin API to get symbol type, instead of invoking
the LTO wrapper.
PR binutils/25640
* plugin.c (plugin_list_entry): Add has_symbol_type.
(add_symbols_v2): New function.
(bfd_plugin_open_input): Don't invoke LTO wrapper if LTO plugin
provides symbol type.
(try_load_plugin): Add LDPT_ADD_SYMBOLS_V2.
(bfd_plugin_canonicalize_symtab): Use LTO plugin symbol type if
available.
---
bfd/plugin.c | 66 +++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 52 insertions(+), 14 deletions(-)
diff --git a/bfd/plugin.c b/bfd/plugin.c
index a0f172d363..f33bc3ddef 100644
--- a/bfd/plugin.c
+++ b/bfd/plugin.c
@@ -136,6 +136,7 @@ struct plugin_list_entry
asymbol **real_syms;
int lto_nsyms;
const struct ld_plugin_symbol *lto_syms;
+ bfd_boolean has_symbol_type;
struct plugin_list_entry *next;
@@ -503,6 +504,14 @@ add_symbols (void * handle,
return LDPS_OK;
}
+static enum ld_plugin_status
+add_symbols_v2 (void *handle, int nsyms,
+ const struct ld_plugin_symbol *syms)
+{
+ current_plugin->has_symbol_type = TRUE;
+ return add_symbols (handle, nsyms, (struct ld_plugin_symbol *) syms);
+}
+
int
bfd_plugin_open_input (bfd *ibfd, struct ld_plugin_input_file *file)
{
@@ -560,7 +569,8 @@ try_claim (bfd *abfd)
current_plugin->claim_file (&file, &claimed);
if (claimed)
{
- if (current_plugin->all_symbols_read)
+ if (current_plugin->all_symbols_read
+ && !current_plugin->has_symbol_type)
{
struct plugin_data_struct *plugin_data
= abfd->tdata.plugin_data;
@@ -602,7 +612,7 @@ try_load_plugin (const char *pname,
bfd *abfd, bfd_boolean build_list_p)
{
void *plugin_handle;
- struct ld_plugin_tv tv[12];
+ struct ld_plugin_tv tv[13];
int i;
ld_plugin_onload onload;
enum ld_plugin_status status;
@@ -665,6 +675,10 @@ try_load_plugin (const char *pname,
tv[i].tv_tag = LDPT_ADD_SYMBOLS;
tv[i].tv_u.tv_add_symbols = add_symbols;
+ ++i;
+ tv[i].tv_tag = LDPT_ADD_SYMBOLS_V2;
+ tv[i].tv_u.tv_add_symbols = add_symbols_v2;
+
if (get_lto_wrapper (plugin_list_iter))
{
++i;
@@ -977,9 +991,15 @@ bfd_plugin_canonicalize_symtab (bfd *abfd,
struct plugin_data_struct *plugin_data = abfd->tdata.plugin_data;
long nsyms = plugin_data->nsyms;
const struct ld_plugin_symbol *syms = plugin_data->syms;
- static asection fake_section
- = BFD_FAKE_SECTION (fake_section, NULL, "plug", 0,
+ static asection fake_text_section
+ = BFD_FAKE_SECTION (fake_text_section, NULL, "plug", 0,
SEC_ALLOC | SEC_LOAD | SEC_CODE | SEC_HAS_CONTENTS);
+ static asection fake_data_section
+ = BFD_FAKE_SECTION (fake_data_section, NULL, "plug", 0,
+ SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS);
+ static asection fake_bss_section
+ = BFD_FAKE_SECTION (fake_bss_section, NULL, "plug", 0,
+ SEC_ALLOC);
static asection fake_common_section
= BFD_FAKE_SECTION (fake_common_section, NULL, "plug", 0, SEC_IS_COMMON);
int i, j;
@@ -1014,16 +1034,34 @@ bfd_plugin_canonicalize_symtab (bfd *abfd,
break;
case LDPK_DEF:
case LDPK_WEAKDEF:
- s->section = &fake_section;
- if (real_nsyms)
- /* Use real LTO symbols if possible. */
- for (j = 0; j < real_nsyms; j++)
- if (real_syms[j]->name
- && strcmp (syms[i].name, real_syms[j]->name) == 0)
- {
- s->section = real_syms[j]->section;
- break;
- }
+ if (current_plugin->has_symbol_type)
+ switch (syms[i].symbol_type)
+ {
+ case LDST_UNKNOWN:
+ /* What is the best fake section for LDST_UNKNOWN? */
+ case LDST_FUNCTION:
+ s->section = &fake_text_section;
+ break;
+ case LDST_VARIABLE:
+ if (syms[i].section_flags == LDSSS_BSS)
+ s->section = &fake_bss_section;
+ else
+ s->section = &fake_data_section;
+ break;
+ }
+ else
+ {
+ s->section = &fake_text_section;
+ if (real_nsyms)
+ /* Use real LTO symbols if possible. */
+ for (j = 0; j < real_nsyms; j++)
+ if (real_syms[j]->name
+ && strcmp (syms[i].name, real_syms[j]->name) == 0)
+ {
+ s->section = real_syms[j]->section;
+ break;
+ }
+ }
break;
default:
BFD_ASSERT (0);
--
2.25.1
prev parent reply other threads:[~2020-03-18 12:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-18 12:06 RFC [PATCH 0/2] " H.J. Lu
2020-03-18 12:06 ` RFC [PATCH 1/2] Update include/plugin-api.h H.J. Lu
2020-03-19 16:09 ` [PATCH] " H.J. Lu
2020-03-20 2:33 ` Alan Modra
2020-03-18 12:06 ` H.J. Lu [this message]
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