On 3/10/20 12:24 PM, Richard Biener wrote:
Not sure how symtab is encoded right now but we also could have
Ok, right now I don't see symtab entry much extensible.
But what am I suggesting is to parse LTO bytecode version and then
process conditional parsing of lto_symtab section.
Thoughts?
Martin
>From 017dd9cba9a0222104682bef094d9f5057d2c9ae Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Fri, 6 Mar 2020 18:09:35 +0100
Subject: [PATCH] API extension for binutils (type of symbols).
gcc/ChangeLog:
2020-03-09 Martin Liska <mli...@suse.cz>
* lto-streamer-out.c (write_symbol): Stream
symbol type.
include/ChangeLog:
2020-03-09 Martin Liska <mli...@suse.cz>
* lto-symtab.h (enum gcc_plugin_symbol_type): New.
* plugin-api.h (struct ld_plugin_symbol): New member
symbols_type.
(enum ld_plugin_symbol_type): New.
(enum ld_plugin_tag): Add new tag LDPT_GET_SYMBOLS_V4.
lto-plugin/ChangeLog:
2020-03-09 Martin Liska <mli...@suse.cz>
* lto-plugin.c (parse_table_entry): Parse symbol type.
(LTO_LTO_PREFIX): New.
(LTO_LTO_PREFIX_LEN): New.
(struct lto_section): New.
---
gcc/lto-streamer-out.c | 14 ++++++++++++
include/lto-symtab.h | 8 +++++++
include/plugin-api.h | 14 +++++++++++-
lto-plugin/lto-plugin.c | 48 ++++++++++++++++++++++++++++++++++++++++-
4 files changed, 82 insertions(+), 2 deletions(-)
diff --git a/gcc/lto-streamer-out.c b/gcc/lto-streamer-out.c
index cea5e71cffb..ead606eb665 100644
--- a/gcc/lto-streamer-out.c
+++ b/gcc/lto-streamer-out.c
@@ -45,6 +45,7 @@ along with GCC; see the file COPYING3. If not see
#include "print-tree.h"
#include "tree-dfa.h"
#include "file-prefix-map.h" /* remap_debug_filename() */
+#include "output.h"
static void lto_write_tree (struct output_block*, tree, bool);
@@ -2773,6 +2774,19 @@ write_symbol (struct streamer_tree_cache_d *cache,
lto_write_data (&c, 1);
c = (unsigned char) visibility;
lto_write_data (&c, 1);
+
+ gcc_plugin_symbol_type st;
+ if (TREE_CODE (t) == VAR_DECL)
+ {
+ section *s = get_variable_section (t, false);
+ st = (s->common.flags & SECTION_BSS
+ ? GCCST_VARIABLE_BSS : GCCST_VARIABLE_DATA);
+ }
+ else
+ st = GCCST_FUNCTION;
+
+ c = (unsigned char) st;
+ lto_write_data (&c, 1);
lto_write_data (&size, 8);
lto_write_data (&slot_num, 4);
}
diff --git a/include/lto-symtab.h b/include/lto-symtab.h
index 0ce0de10121..901bc3585c2 100644
--- a/include/lto-symtab.h
+++ b/include/lto-symtab.h
@@ -38,4 +38,12 @@ enum gcc_plugin_symbol_visibility
GCCPV_HIDDEN
};
+enum gcc_plugin_symbol_type
+{
+ GCCST_UNKNOWN,
+ GCCST_FUNCTION,
+ GCCST_VARIABLE_DATA,
+ GCCST_VARIABLE_BSS
+};
+
#endif /* GCC_LTO_SYMTAB_H */
diff --git a/include/plugin-api.h b/include/plugin-api.h
index 09e1202df07..794a2dcc4ee 100644
--- a/include/plugin-api.h
+++ b/include/plugin-api.h
@@ -92,6 +92,7 @@ struct ld_plugin_symbol
uint64_t size;
char *comdat_key;
int resolution;
+ int symbol_type;
};
/* An object's section. */
@@ -123,6 +124,16 @@ enum ld_plugin_symbol_visibility
LDPV_HIDDEN
};
+/* The type of the symbol. */
+
+enum ld_plugin_symbol_type
+{
+ LDST_UNKNOWN,
+ LDST_FUNCTION,
+ LDST_VARIABLE_DATA,
+ LDST_VARIABLE_BSS
+};
+
/* How a symbol is resolved. */
enum ld_plugin_symbol_resolution
@@ -431,7 +442,8 @@ enum ld_plugin_tag
LDPT_GET_INPUT_SECTION_ALIGNMENT = 29,
LDPT_GET_INPUT_SECTION_SIZE = 30,
LDPT_REGISTER_NEW_INPUT_HOOK = 31,
- LDPT_GET_WRAP_SYMBOLS = 32
+ LDPT_GET_WRAP_SYMBOLS = 32,
+ LDPT_GET_SYMBOLS_V4 = 33,
};
/* The plugin transfer vector. */
diff --git a/lto-plugin/lto-plugin.c b/lto-plugin/lto-plugin.c
index c307fc871bf..33afae9afb6 100644
--- a/lto-plugin/lto-plugin.c
+++ b/lto-plugin/lto-plugin.c
@@ -90,6 +90,8 @@ along with this program; see the file COPYING3. If not see
#define LTO_SECTION_PREFIX ".gnu.lto_.symtab"
#define LTO_SECTION_PREFIX_LEN (sizeof (LTO_SECTION_PREFIX) - 1)
+#define LTO_LTO_PREFIX ".gnu.lto_.lto"
+#define LTO_LTO_PREFIX_LEN (sizeof (LTO_LTO_PREFIX) - 1)
#define OFFLOAD_SECTION ".gnu.offload_lto_.opts"
#define OFFLOAD_SECTION_LEN (sizeof (OFFLOAD_SECTION) - 1)
@@ -221,6 +223,20 @@ check_1 (int gate, enum ld_plugin_level level, const char *text)
}
}
+/* Structure that represents LTO ELF section with information
+ about the format. */
+
+struct lto_section
+ {
+ int16_t major_version;
+ int16_t minor_version;
+ unsigned char slim_object: 1;
+ unsigned char compression: 4;
+ int32_t reserved0: 27;
+};
+
+struct lto_section lto_header;
+
/* This little wrapper allows check to be called with a non-integer
first argument, such as a pointer that must be non-NULL. We can't
use c99 bool type to coerce it into range, so we explicitly test. */
@@ -252,6 +268,14 @@ parse_table_entry (char *p, struct ld_plugin_symbol *entry,
LDPV_HIDDEN
};
+ enum ld_plugin_symbol_type symbol_types[] =
+ {
+ LDST_UNKNOWN,
+ LDST_FUNCTION,
+ LDST_VARIABLE_DATA,
+ LDST_VARIABLE_BSS
+ };
+
switch (sym_style)
{
case ss_win32:
@@ -296,6 +320,15 @@ parse_table_entry (char *p, struct ld_plugin_symbol *entry,
entry->visibility = translate_visibility[t];
p++;
+ /* Symbol type was added in GCC 10.1 (LTO version 9.0). */
+ if (lto_header.major_version >= 9)
+ {
+ t = *p;
+ check (t <= 3, LDPL_FATAL, "invalid symbol type found");
+ entry->symbol_type = symbol_types[t];
+ p++;
+ }
+
memcpy (&entry->size, p, sizeof (uint64_t));
p += 8;
@@ -951,7 +984,20 @@ process_symtab (void *data, const char *name, off_t offset, off_t length)
{
struct plugin_objfile *obj = (struct plugin_objfile *)data;
char *s;
- char *secdatastart, *secdata;
+ char *secdatastart = NULL, *secdata;
+
+ if (strncmp (name, LTO_LTO_PREFIX, LTO_LTO_PREFIX_LEN) == 0)
+ {
+ if (offset != lseek (obj->file->fd, offset, SEEK_SET))
+ goto err;
+
+ ssize_t got = read (obj->file->fd, <o_header,
+ sizeof (struct lto_section));
+ if (got != sizeof (struct lto_section))
+ goto err;
+
+ return 1;
+ }
if (strncmp (name, LTO_SECTION_PREFIX, LTO_SECTION_PREFIX_LEN) != 0)
return 1;
--
2.25.1
