From: Fangrui Song <maskray@google.com>
To: binutils@sourceware.org, Alan Modra <amodra@gmail.com>,
Nick Clifton <nickc@redhat.com>
Cc: Luca Boccassi <bluca@debian.org>, Fangrui Song <maskray@google.com>
Subject: [PATCH] ld: Support customized output section type
Date: Tue, 1 Feb 2022 23:10:44 -0800 [thread overview]
Message-ID: <20220202071044.1480421-1-maskray@google.com> (raw)
The current output section type allows to set the ELF section type to
SHT_PROGBITS or SHT_NOLOAD. This patch allows an arbitrary section value
to be specified. Some ELF section type names are supported as well,
e.g.:
note (TYPE=SHT_NOTE) : { BYTE(8) }
init_array (TYPE=14) : { BYTE(14) }
fini_array (TYPE=SHT_FINI_ARRAY) : { BYTE(15) }
bfd/
PR ld/28841
* bfd-in2.h (struct bfd_section): Add type.
(discarded_section): Add field.
* elf.c (elf_fake_sections): Handle bfd_section::type.
* section.c (BFD_FAKE_SECTION): Add field.
* mri.c (mri_draw_tree): Update function call.
ld/
PR ld/28841
* ld.texi: Document new output section type.
* ldlex.l: Add new token TYPE.
* ldgram.y: Handle TYPE=exp.
* ldlang.h: Add type_section to list of section types.
* ldlang.c (lang_add_section): Handle type_section.
(map_input_to_output_sections): Handle type_section.
* testsuite/ld-scripts/output-section-types.t: Add tests.
* testsuite/ld-scripts/output-section-types.d: Update.
---
bfd/bfd-in2.h | 7 ++-
bfd/elf.c | 4 +-
bfd/section.c | 4 +-
ld/ld.texi | 4 ++
ld/ldgram.y | 9 ++--
ld/ldlang.c | 49 ++++++++++++++++---
ld/ldlang.h | 4 +-
ld/ldlex.l | 1 +
ld/mri.c | 4 +-
.../ld-scripts/output-section-types.d | 16 +++---
.../ld-scripts/output-section-types.t | 5 ++
11 files changed, 82 insertions(+), 25 deletions(-)
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 8e815bab624..91ec68d0391 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -1170,6 +1170,9 @@ typedef struct bfd_section
This is used when support for non-contiguous memory regions is enabled. */
struct bfd_section *already_assigned;
+ /* Explicitly specified section type, if non-zero. */
+ unsigned int type;
+
} asection;
/* Relax table contains information about instructions which can
@@ -1352,8 +1355,8 @@ discarded_section (const asection *sec)
/* symbol, symbol_ptr_ptr, */ \
(struct bfd_symbol *) SYM, &SEC.symbol, \
\
- /* map_head, map_tail, already_assigned */ \
- { NULL }, { NULL }, NULL \
+ /* map_head, map_tail, already_assigned, type */ \
+ { NULL }, { NULL }, NULL, 0 \
\
}
diff --git a/bfd/elf.c b/bfd/elf.c
index 14c2c7ba734..1ebe7b425c4 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -3279,7 +3279,9 @@ elf_fake_sections (bfd *abfd, asection *asect, void *fsarg)
/* If the section type is unspecified, we set it based on
asect->flags. */
- if ((asect->flags & SEC_GROUP) != 0)
+ if (asect->type != 0)
+ sh_type = asect->type;
+ else if ((asect->flags & SEC_GROUP) != 0)
sh_type = SHT_GROUP;
else
sh_type = bfd_elf_get_default_section_type (asect->flags);
diff --git a/bfd/section.c b/bfd/section.c
index 899438a1c5e..2de7dbf661a 100644
--- a/bfd/section.c
+++ b/bfd/section.c
@@ -737,8 +737,8 @@ CODE_FRAGMENT
. {* symbol, symbol_ptr_ptr, *} \
. (struct bfd_symbol *) SYM, &SEC.symbol, \
. \
-. {* map_head, map_tail, already_assigned *} \
-. { NULL }, { NULL }, NULL \
+. {* map_head, map_tail, already_assigned, type *} \
+. { NULL }, { NULL }, NULL, 0 \
. \
. }
.
diff --git a/ld/ld.texi b/ld/ld.texi
index fc75e9b3625..e3a1e02ed25 100644
--- a/ld/ld.texi
+++ b/ld/ld.texi
@@ -5490,6 +5490,10 @@ These type names are supported for backward compatibility, and are
rarely used. They all have the same effect: the section should be
marked as not allocatable, so that no memory is allocated for the
section when the program is run.
+@item TYPE = @var{type}
+Set the section type to the integer @var{type}. For the ELF output
+file, some type names (e.g. @code{SHT_NOTE}) are also allowed for
+@var{type}.
@end table
@kindex NOLOAD
diff --git a/ld/ldgram.y b/ld/ldgram.y
index 11c2f219c05..f5e3a834a26 100644
--- a/ld/ldgram.y
+++ b/ld/ldgram.y
@@ -47,6 +47,7 @@
#endif
static enum section_type sectype;
+static etree_type *sectype_value;
static lang_memory_region_type *region;
static bool ldgram_had_keep = false;
@@ -139,6 +140,7 @@ static int error_index;
%token LD_FEATURE
%token NOLOAD DSECT COPY INFO OVERLAY
%token READONLY
+%token TYPE
%token DEFINED TARGET_K SEARCH_DIR MAP ENTRY
%token <integer> NEXT
%token SIZEOF ALIGNOF ADDR LOADADDR MAX_K MIN_K
@@ -1058,9 +1060,8 @@ section: NAME
{
ldlex_popstate ();
ldlex_wild ();
- lang_enter_output_section_statement($1, $3, sectype,
- $5, $7, $4,
- $8, $6);
+ lang_enter_output_section_statement ($1, $3, sectype,
+ sectype_value, $5, $7, $4, $8, $6);
}
'{'
statement_list_opt
@@ -1131,7 +1132,7 @@ type:
| INFO { sectype = noalloc_section; }
| OVERLAY { sectype = noalloc_section; }
| READONLY { sectype = readonly_section; }
- ;
+ | TYPE '=' exp { sectype = type_section; sectype_value = $3; }
atype:
'(' type ')'
diff --git a/ld/ldlang.c b/ld/ldlang.c
index 5dd3df12a0f..a0a3c09f9a9 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -1891,8 +1891,8 @@ lang_insert_orphan (asection *s,
address = exp_intop (0);
os_tail = (lang_output_section_statement_type **) lang_os_list.tail;
- os = lang_enter_output_section_statement (secname, address, normal_section,
- NULL, NULL, NULL, constraint, 0);
+ os = lang_enter_output_section_statement (
+ secname, address, normal_section, 0, NULL, NULL, NULL, constraint, 0);
if (add_child == NULL)
add_child = &os->children;
@@ -2635,6 +2635,7 @@ lang_add_section (lang_statement_list_type *ptr,
case normal_section:
case overlay_section:
case first_overlay_section:
+ case type_section:
break;
case noalloc_section:
flags &= ~SEC_ALLOC;
@@ -4209,6 +4210,7 @@ map_input_to_output_sections
{
lang_output_section_statement_type *tos;
flagword flags;
+ unsigned int type = 0;
switch (s->header.type)
{
@@ -4261,6 +4263,37 @@ map_input_to_output_sections
case noalloc_section:
flags = SEC_HAS_CONTENTS;
break;
+ case type_section:
+ if (os->sectype_value->type.node_class == etree_name
+ && os->sectype_value->type.node_code == NAME)
+ {
+ const char *name = os->sectype_value->name.name;
+ if (strcmp (name, "SHT_PROGBITS") == 0)
+ type = SHT_PROGBITS;
+ else if (strcmp (name, "SHT_NOTE") == 0)
+ type = SHT_NOTE;
+ else if (strcmp (name, "SHT_NOBITS") == 0)
+ type = SHT_NOBITS;
+ else if (strcmp (name, "SHT_INIT_ARRAY") == 0)
+ type = SHT_INIT_ARRAY;
+ else if (strcmp (name, "SHT_FINI_ARRAY") == 0)
+ type = SHT_FINI_ARRAY;
+ else if (strcmp (name, "SHT_PREINIT_ARRAY") == 0)
+ type = SHT_PREINIT_ARRAY;
+ else
+ einfo (_ ("%F%P: invalid type for output section `%s'\n"),
+ os->name);
+ }
+ else
+ {
+ exp_fold_tree_no_dot (os->sectype_value);
+ if (expld.result.valid_p)
+ type = expld.result.value;
+ else
+ einfo (_ ("%F%P: invalid type for output section `%s'\n"),
+ os->name);
+ }
+ break;
case readonly_section:
flags |= SEC_READONLY;
break;
@@ -4276,6 +4309,7 @@ map_input_to_output_sections
init_os (os, flags | SEC_READONLY);
else
os->bfd_section->flags |= flags;
+ os->bfd_section->type = type;
break;
case lang_input_section_enum:
break;
@@ -7564,6 +7598,7 @@ lang_output_section_statement_type *
lang_enter_output_section_statement (const char *output_section_statement_name,
etree_type *address_exp,
enum section_type sectype,
+ etree_type *sectype_value,
etree_type *align,
etree_type *subalign,
etree_type *ebase,
@@ -7581,10 +7616,12 @@ lang_enter_output_section_statement (const char *output_section_statement_name,
os->addr_tree = address_exp;
}
os->sectype = sectype;
- if (sectype != noload_section)
- os->flags = SEC_NO_FLAGS;
- else
+ if (sectype == type_section)
+ os->sectype_value = sectype_value;
+ else if (sectype == noload_section)
os->flags = SEC_NEVER_LOAD;
+ else
+ os->flags = SEC_NO_FLAGS;
os->block_value = 1;
/* Make next things chain into subchain of this. */
@@ -8901,7 +8938,7 @@ lang_enter_overlay_section (const char *name)
etree_type *size;
lang_enter_output_section_statement (name, overlay_vma, overlay_section,
- 0, overlay_subalign, 0, 0, 0);
+ 0, 0, overlay_subalign, 0, 0, 0);
/* If this is the first section, then base the VMA of future
sections on this one. This will work correctly even if `.' is
diff --git a/ld/ldlang.h b/ld/ldlang.h
index 0d057c9bee9..20b953eeac6 100644
--- a/ld/ldlang.h
+++ b/ld/ldlang.h
@@ -122,6 +122,7 @@ enum section_type
overlay_section,
noload_section,
noalloc_section,
+ type_section,
readonly_section
};
@@ -166,6 +167,7 @@ typedef struct lang_output_section_statement_struct
int constraint;
flagword flags;
enum section_type sectype;
+ etree_type *sectype_value;
unsigned int processed_vma : 1;
unsigned int processed_lma : 1;
unsigned int all_input_readonly : 1;
@@ -545,7 +547,7 @@ extern void lang_add_output
(const char *, int from_script);
extern lang_output_section_statement_type *lang_enter_output_section_statement
(const char *, etree_type *, enum section_type, etree_type *, etree_type *,
- etree_type *, int, int);
+ etree_type *, etree_type *, int, int);
extern void lang_final
(void);
extern void lang_relax_sections
diff --git a/ld/ldlex.l b/ld/ldlex.l
index 78db16e3a48..c38b46b9336 100644
--- a/ld/ldlex.l
+++ b/ld/ldlex.l
@@ -323,6 +323,7 @@ V_IDENTIFIER [*?.$_a-zA-Z\[\]\-\!\^\\]([*?.$_a-zA-Z0-9\[\]\-\!\^\\]|::)*
<EXPRESSION>"DSECT" { RTOKEN(DSECT); }
<EXPRESSION>"COPY" { RTOKEN(COPY); }
<EXPRESSION>"INFO" { RTOKEN(INFO); }
+<EXPRESSION>"TYPE" { RTOKEN(TYPE); }
<SCRIPT,EXPRESSION>"ONLY_IF_RO" { RTOKEN(ONLY_IF_RO); }
<SCRIPT,EXPRESSION>"ONLY_IF_RW" { RTOKEN(ONLY_IF_RW); }
<SCRIPT,EXPRESSION>"SPECIAL" { RTOKEN(SPECIAL); }
diff --git a/ld/mri.c b/ld/mri.c
index b428ab0d0bf..5749870ef1e 100644
--- a/ld/mri.c
+++ b/ld/mri.c
@@ -210,8 +210,8 @@ mri_draw_tree (void)
base = p->vma ? p->vma : exp_nameop (NAME, ".");
lang_enter_output_section_statement (p->name, base,
- p->ok_to_load ? normal_section : noload_section,
- align, subalign, NULL, 0, 0);
+ p->ok_to_load ? normal_section : noload_section, 0,
+ align, subalign, NULL, 0, 0);
base = 0;
tmp = (struct wildcard_list *) xmalloc (sizeof *tmp);
tmp->next = NULL;
diff --git a/ld/testsuite/ld-scripts/output-section-types.d b/ld/testsuite/ld-scripts/output-section-types.d
index ab124fa4dd7..56b88ce6342 100644
--- a/ld/testsuite/ld-scripts/output-section-types.d
+++ b/ld/testsuite/ld-scripts/output-section-types.d
@@ -1,13 +1,15 @@
#ld: -Toutput-section-types.t
#source: align2a.s
-#objdump: -h
+#readelf: -S --wide
#target: [is_elf_format]
#...
- . \.rom.*
-[ ]+ALLOC, READONLY
- . \.ro.*
-[ ]+CONTENTS, ALLOC, LOAD, READONLY, DATA
- . \.over.*
-[ ]+CONTENTS, READONLY
+.* .rom +NOBITS +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +00 +A +[0-9] +0 +[1248]
+.* .ro +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +00 +A +[0-9] +0 +[1248]
+.* .over +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +00 + +[0-9] +0 +[1248]
+.* progbits +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +00 +A +[0-9] +0 +[1248]
+.* note +NOTE +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +00 +A +[0-9] +0 +[1248]
+.* init_array +INIT_ARRAY +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +0[48] +A +[0-9] +0 +[1248]
+.* fini_array +FINI_ARRAY +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +0[48] +A +[0-9] +0 +[1248]
+.* preinit_array +PREINIT_ARRAY +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +0[48] +A +[0-9] +0 +[1248]
#pass
diff --git a/ld/testsuite/ld-scripts/output-section-types.t b/ld/testsuite/ld-scripts/output-section-types.t
index d8fdfda1a03..834e5869d79 100644
--- a/ld/testsuite/ld-scripts/output-section-types.t
+++ b/ld/testsuite/ld-scripts/output-section-types.t
@@ -2,6 +2,11 @@ SECTIONS {
.rom (NOLOAD) : { LONG(1234); }
.ro (READONLY) : { LONG(5678); }
.over (OVERLAY) : { LONG(0123); }
+ progbits (TYPE=SHT_PROGBITS) : { BYTE(1) }
+ note (TYPE=SHT_NOTE) : { BYTE(8) }
+ init_array (TYPE=14) : { BYTE(14) }
+ fini_array (TYPE=SHT_FINI_ARRAY) : { BYTE(15) }
+ preinit_array (TYPE=SHT_PREINIT_ARRAY) : { BYTE(16) }
/DISCARD/ : { *(*) }
}
--
2.35.0.rc2.247.g8bbb082509-goog
next reply other threads:[~2022-02-02 7:11 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-02 7:10 Fangrui Song [this message]
2022-02-02 11:36 ` Nick Clifton
2022-02-02 11:46 ` Luca Boccassi
2022-02-02 18:32 ` Fangrui Song
2022-02-03 18:36 ` Luca Boccassi
2022-02-03 19:46 ` Fangrui Song
2022-02-03 20:04 ` Luca Boccassi
2022-02-03 20:48 ` Fangrui Song
2022-02-04 16:05 ` Michael Matz
2022-02-21 19:35 ` Mike Frysinger
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