[PATCH][WIP] libiberty: Support for relocation output
This patch teaches libiberty to output X86-64 Relocations.
>From d3b2d168369e76a6fac2b3b3cbd591ccf22ea8ea Mon Sep 17 00:00:00 2001
From: Rishi Raj
Date: Mon, 23 Oct 2023 06:22:44 +0530
Subject: [PATCH 1/3] Extended libiberty to output X86_64 relocations
Signed-off-by: Rishi Raj
---
include/simple-object.h | 11 +-
libiberty/simple-object-common.h | 28 ++-
libiberty/simple-object-elf.c| 317 ++-
libiberty/simple-object.c| 95 +++--
4 files changed, 387 insertions(+), 64 deletions(-)
diff --git a/include/simple-object.h b/include/simple-object.h
index 3a14184b12c..17ecd856636 100644
--- a/include/simple-object.h
+++ b/include/simple-object.h
@@ -186,6 +186,14 @@ simple_object_write_add_data (simple_object_write
*simple_object,
simple_object_write_section *section,
const void *buffer, size_t size,
int copy, int *err);
+/* Add relocation to SECTION in SIMPLE_OBJECT */
+void
+simple_object_write_add_relocation (simple_object_write_section *section,
+ unsigned long offset, long addend, const char *name, unsigned long
rel_sec_idx);
+
+/* Modifies simple object section buffer at offset. */
+void simple_object_modify_buffer (simple_object_write_section *section,
+ unsigned long offset, unsigned char *buffer, int copy);
/* Write the complete object file to DESCRIPTOR, an open file
descriptor. This returns NULL on success. On error this returns
@@ -199,7 +207,8 @@ simple_object_write_to_file (simple_object_write
*simple_object,
object_write_to_file function*/
extern void
simple_object_write_add_symbol(simple_object_write *sobj, const char *name,
-size_t size, unsigned int align);
+ unsigned int value, size_t size, unsigned char bind,
+ unsigned char type, unsigned short int shndx, unsigned char
st_other);
/* Release all resources associated with SIMPLE_OBJECT, including any
simple_object_write_section's that may have been created. */
diff --git a/libiberty/simple-object-common.h
b/libiberty/simple-object-common.h
index df99c9d85ac..1dc06908eec 100644
--- a/libiberty/simple-object-common.h
+++ b/libiberty/simple-object-common.h
@@ -73,9 +73,17 @@ struct simple_object_symbol_struct
/*The name of this symbol. */
char *name;
/* Symbol value */
- unsigned int align;
+ unsigned int value;
/* Symbol size */
size_t size;
+ /*Symbol binding*/
+ unsigned char bind;
+ /*Symbol info*/
+ unsigned char type;
+ /*Symbol section index*/
+ unsigned short int shndx;
+ /* Symbol visibility */
+ unsigned char st_other;
};
/* A section in an object file being created. */
@@ -93,6 +101,11 @@ struct simple_object_write_section_struct
struct simple_object_write_section_buffer *buffers;
/* The last data attached to this section. */
struct simple_object_write_section_buffer *last_buffer;
+ /*The first relocation attached to this section. */
+ struct simple_object_write_section_relocation *relocations;
+ /* The last relocation attache to this section. */
+ struct simple_object_write_section_relocation *last_relocation;
+
};
/* Data attached to a section. */
@@ -108,6 +121,19 @@ struct simple_object_write_section_buffer
/* A buffer to free, or NULL. */
void *free_buffer;
};
+struct simple_object_write_section_relocation
+{
+ /* The next relocation for this section. */
+ struct simple_object_write_section_relocation *next;
+ /* The offset. */
+ unsigned long offset;
+ /* Addend */
+ long addend;
+ /* Relocation symbol */
+ const char *name;
+ /* Relocation symbol st_shndx wrt .debug_info index */
+ unsigned long rel_sec_idx;
+};
/* The number of bytes we read from the start of the file to pass to
the match function. */
diff --git a/libiberty/simple-object-elf.c b/libiberty/simple-object-elf.c
index 86b7a27dc74..0bbaf4b489f 100644
--- a/libiberty/simple-object-elf.c
+++ b/libiberty/simple-object-elf.c
@@ -238,6 +238,7 @@ typedef struct
#define STT_NOTYPE 0 /* Symbol type is unspecified */
#define STT_OBJECT 1 /* Symbol is a data object */
#define STT_FUNC 2 /* Symbol is a code object */
+#define STT_SECTION 3 /* Symbol is associate with a section */
#define STT_TLS 6 /* Thread local data object */
#define STT_GNU_IFUNC 10 /* Symbol is an indirect code object */
@@ -248,6 +249,63 @@ typedef struct
#define STV_DEFAULT 0 /* Visibility is specified by binding type */
#define STV_HIDDEN 2 /* Can only be seen inside currect component */
+typedef struct
+{
+ unsigned char r_offset[4]; /* Address */
+ unsigned char r_info[4]; /* relocation type and symbol index */
+} Elf32_External_Rel;
+
+typedef struct
+{
+ unsigned char r_offset[8]; /* Address */
+ unsigned char r_info[8]; /* Relocation type and symbol index */
+} Elf64_External_Rel;
+typedef struct
+{
+ unsigned char r_offset[4]; /* Address */
+ unsigned char r_info[4]; /* Relocation type and symbol index */
+ char r_addend[4]; /
Re: [PATCH][WIP] libiberty: Support for relocation output
On Mon, 23 Oct 2023 at 16:30, Jan Hubicka wrote:
> > This patch teaches libiberty to output X86-64 Relocations.
> Hello,
> for actual patch submission you will need to add changelog :)
>
I know, right :).
> > diff --git a/libiberty/simple-object-elf.c
> b/libiberty/simple-object-elf.c
> > index 86b7a27dc74..0bbaf4b489f 100644
> > --- a/libiberty/simple-object-elf.c
> > +++ b/libiberty/simple-object-elf.c
> > @@ -238,6 +238,7 @@ typedef struct
> > #define STT_NOTYPE 0 /* Symbol type is unspecified */
> > #define STT_OBJECT 1 /* Symbol is a data object */
> > #define STT_FUNC 2 /* Symbol is a code object */
> > +#define STT_SECTION 3 /* Symbol is associate with a section */
> Associated I guess.
> > #define STT_TLS 6 /* Thread local data object */
> > #define STT_GNU_IFUNC 10 /* Symbol is an indirect code object */
> >
> > @@ -248,6 +249,63 @@ typedef struct
> > #define STV_DEFAULT 0 /* Visibility is specified by binding type */
> > #define STV_HIDDEN 2 /* Can only be seen inside currect component */
> >
> > +typedef struct
> > +{
> > + unsigned char r_offset[4]; /* Address */
> > + unsigned char r_info[4]; /* relocation type and symbol index */
> > +} Elf32_External_Rel;
> > +
> > +typedef struct
> > +{
> > + unsigned char r_offset[8]; /* Address */
> > + unsigned char r_info[8]; /* Relocation type and symbol index */
> > +} Elf64_External_Rel;
> > +typedef struct
> > +{
> > + unsigned char r_offset[4]; /* Address */
> > + unsigned char r_info[4]; /* Relocation type and symbol index */
> > + char r_addend[4]; /* Addend */
> > +} Elf32_External_Rela;
> > +typedef struct
> > +{
> > + unsigned char r_offset[8]; /* Address */
> > + unsigned char r_info[8]; /* Relocation type and symbol index */
> > + unsigned char r_addend[8]; /* Addend */
> > +} Elf64_External_Rela;
> > +
> > +/* How to extract and insert information held in the r_info field. */
> > +
> > +#define ELF32_R_SYM(val) ((val) >> 8)
> > +#define ELF32_R_TYPE(val) ((val) & 0xff)
> > +#define ELF32_R_INFO(sym, type) (((sym) << 8) + ((type) & 0xff))
> > +
> > +#define ELF64_R_SYM(i) ((i) >> 32)
> > +#define ELF64_R_TYPE(i) ((i) & 0x)
> > +#define ELF64_R_INFO(sym,type) unsigned long) (sym)) << 32) +
> (type))
> > +
> > +/* AMD x86-64 relocations. */
> > +#define R_X86_64_NONE 0 /* No reloc */
> > +#define R_X86_64_64 1 /* Direct 64 bit */
> > +#define R_X86_64_PC32 2 /* PC relative 32 bit signed */
> > +#define R_X86_64_GOT32 3 /* 32 bit GOT entry */
> > +#define R_X86_64_PLT32 4 /* 32 bit PLT address */
> > +#define R_X86_64_COPY 5 /* Copy symbol at runtime */
> > +#define R_X86_64_GLOB_DAT 6 /* Create GOT entry */
> > +#define R_X86_64_JUMP_SLOT 7 /* Create PLT entry */
> > +#define R_X86_64_RELATIVE 8 /* Adjust by program base */
> > +#define R_X86_64_GOTPCREL 9 /* 32 bit signed PC relative
> > + offset to GOT */
> > +#define R_X86_64_32 10 /* Direct 32 bit zero extended */
> > +#define R_X86_64_32S 11 /* Direct 32 bit sign extended */
> > +#define R_X86_64_16 12 /* Direct 16 bit zero extended */
>
> This will eventually need to go into per-architecture table.
> You support only those needed for Dwarf2out ouptut, right?
>
Yeah, as of now.
>
> I think we need Iant's opinion on thi part of patch (he is the
> maintainer of simple-object) but to me it looks reasonable. For longer
> term it will be necessary to think how to make this extensible to other
> architectures without writting too much of code. (have some more
> declarative way to specify relocations we output)
>
Make sense.
>
> Honza
>
Re: [PATCH][WIP] dwarf2out: extend to output debug section directly to object file during debug_early phase
On Mon, 23 Oct 2023 at 18:18, Jan Hubicka wrote:
> Hello,
> thanks for the patch.
>
> Overall it looks in right direction except for the code duplication in
> output_die and friends.
> > +/* Given a die and id, produce the appropriate abbreviations
> > + directly to lto object file */
> > +
> > +static void
> > +output_die_abbrevs_to_object_file(unsigned long abbrev_id, dw_die_ref
> > abbrev)
> > +{
> > + unsigned ix;
> > + dw_attr_node *a_attr;
> > +
> > + output_data_uleb128_to_object_file(abbrev_id);
> > + output_data_uleb128_to_object_file(abbrev->die_tag);
> > +
> > +
> > + if (abbrev->die_child != NULL)
> > +output_data_to_object_file(1,DW_children_yes);
> > + else
> > +output_data_to_object_file(1,DW_children_no);
> > +
> > + for (ix = 0; vec_safe_iterate (abbrev->die_attr, ix, &a_attr); ix++)
> > +{
> > + output_data_uleb128_to_object_file(a_attr->dw_attr);
> > + output_value_format_to_object_file(a_attr);
> > + if (value_format (a_attr) == DW_FORM_implicit_const)
> > + {
> > + if (AT_class (a_attr) == dw_val_class_file_implicit)
> > +{
> > + int f = maybe_emit_file (a_attr->dw_attr_val.v.val_file);
> > + output_data_sleb128_to_object_file(f);
> > +}
> > + else
> > + output_data_sleb128_to_object_file(a_attr->dw_attr_val.v.val_int);
> > + }
> > +}
> > +
> > + output_data_to_object_file (1, 0);
> > + output_data_to_object_file (1, 0);
>
> So this basically renames dw2_asm_output_data to
> output_data_to_object_file and similarly for other output functions.
>
> What would be main problems of making dw2_asm_* functions to do the
> right thing when outputting to object file?
> Either by conditionals or turning them to virtual functions/hooks as
> Richi suggested?
>
I think it's doable via conditionals. Can you explain the second approach
in more detail?
>
> It may be performance critical how quickly we sput out the bytecode.
> In future we may templateize this, but right now it is likely premature
> optimization.
>
Cool.
> >
> > +struct lto_simple_object
> lto_simple_object is declared in lto frontend. Why do you need to
> duplicate it here?
>
> It looks like adding relocations should be abstracted by lto API,
> so you don't need to look inside this structure that is
> lto/lto-object.cc only.
>
I should have taken this approach, but instead, I exposed simple objects to
dwarf2out.
That's the reason to duplicate the above struct. I will take care of this
while refactoring
and abstracting it by lto API
>
> > +/* Output one line number table into the .debug_line section. */
> > +
> > +static void
> > +output_one_line_info_table (dw_line_info_table *table)
> It is hard to tell from the diff. Did you just moved these functions
> earlier in source file?
>
Yeah. I will refactor the dwarf2out soon to clear these confusions.
--
Rishi
>
> Honza
>
[COMMITTED] MAINTAINERS file: Added myself to Write After Approval and DCO
From 50cb9df7209125f9466336d23efdd4fbeda9c4d5 Mon Sep 17 00:00:00 2001 From: rsh-raj Date: Fri, 30 Jun 2023 16:04:48 +0530 Subject: [PATCH] MAINTAINERS file: Added myself to Write After Approval and DCO ChangeLog: 2023-06-30 Rishi Raj * MAINTAINERS: Added myself to Write After Approval and DCO --- MAINTAINERS | 2 ++ 1 file changed, 2 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index bac773ad0af..2a0eb5b52b5 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -610,6 +610,7 @@ Hafiz Abid Qadeer Yao Qi Jerry Quinn Navid Rahimi +Rishi Raj Easwaran Raman Joe Ramsay Rolf Rasmussen @@ -749,6 +750,7 @@ Immad Mir Gaius Mulley Siddhesh Poyarekar Navid Rahimi +Rishi Raj Trevor Saunders Bill Schmidt Nathan Sidwell -- 2.40.1
[PATCH] lto: Bypass assembler when generating LTO object files. & libiberty: lto: Addition of .symtab in elf file.
This series of two patches enables the output of the LTO object file
without an assembler. As of now, .symtab is emitted with __gnu_lto_slim
symbol. To test, follow the instructions in the commit
message of patch 1. Also, as suggested by Honza, I am putting these patches
on devel/bypass-asm branch.
>From 46c766d242fd248abc49201cf6419735c8415a6f Mon Sep 17 00:00:00 2001
From: Rishi Raj
Date: Sat, 1 Jul 2023 10:28:11 +0530
Subject: [PATCH 1/2] lto: Bypass assembler when generating LTO object files.
This patch applies Jan Hubicka previous patch on current sources.
Now the compiler is able to produce object files without assembler,
although
a lot of things are missing, such as __lto_slim symbol, debug symbols
etc. They will be added in future patches. To test this current patch,
use these commands below.
1) ./xgcc -B ./ -O3 a.c -flto -S -fbypass-asm=crtbegin.o -o a.o
2) ./xgcc -B ./ -O2 a.o -flto
3) ./a.out
We are currently working with elf-only support (mach-o, coff, xcoff etc
will be dealt later) so this will only work on a linux machine. I have
tested
this on my machine ( Arch linux, Machine: Advanced Micro Devices
X86-64) and
all LTO test cases passed as expected.
gcc/ChangeLog:
* Makefile.in:
* common.opt:
* langhooks.cc (lhd_begin_section):
(lhd_append_data):
(lhd_end_section):
* lto/lto-object.cc: Moved to...
* lto-object.cc: ...here.
* lto-streamer.h (struct lto_section_slot):
(struct lto_section_list):
(struct lto_file):
(lto_obj_file_open):
(lto_obj_file_close):
(lto_obj_build_section_table):
(lto_obj_create_section_hash_table):
(lto_obj_begin_section):
(lto_obj_append_data):
(lto_obj_end_section):
(lto_set_current_out_file):
(lto_get_current_out_file):
* toplev.cc (compile_file):
(lang_dependent_init):
gcc/lto/ChangeLog:
* Make-lang.in:
* lto-common.cc (lto_file_read):
* lto-lang.cc:
* lto.h (struct lto_file):
(lto_obj_file_open):
(lto_obj_file_close):
(struct lto_section_list):
(lto_obj_build_section_table):
(lto_obj_create_section_hash_table):
(lto_obj_begin_section):
(lto_obj_append_data):
(lto_obj_end_section):
(lto_set_current_out_file):
(lto_get_current_out_file):
(struct lto_section_slot):
Signed-off-by: Rishi Raj
---
gcc/Makefile.in | 1 +
gcc/common.opt | 3 +++
gcc/langhooks.cc| 29 +++-
gcc/{lto => }/lto-object.cc | 29 +---
gcc/lto-streamer.h | 35 ++
gcc/lto/Make-lang.in| 4 ++--
gcc/lto/lto-common.cc | 3 ++-
gcc/lto/lto-lang.cc | 1 +
gcc/lto/lto.h | 38 -
gcc/toplev.cc | 19 ---
10 files changed, 110 insertions(+), 52 deletions(-)
rename gcc/{lto => }/lto-object.cc (94%)
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index c478ec85201..c9ae222fb59 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1560,6 +1560,7 @@ OBJS = \
lto-section-out.o \
lto-opts.o \
lto-compress.o \
+ lto-object.o \
mcf.o \
mode-switching.o \
modulo-sched.o \
diff --git a/gcc/common.opt b/gcc/common.opt
index 25f650e2dae..ba7a18ece8c 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1169,6 +1169,9 @@ fbtr-bb-exclusive
Common Ignore
Does nothing. Preserved for backward compatibility.
+fbypass-asm=
+Common Joined Var(flag_bypass_asm)
+
fcallgraph-info
Common RejectNegative Var(flag_callgraph_info) Init(NO_CALLGRAPH_INFO);
Output callgraph information on a per-file basis.
diff --git a/gcc/langhooks.cc b/gcc/langhooks.cc
index 9a1a9eccca9..a76ed974d58 100644
--- a/gcc/langhooks.cc
+++ b/gcc/langhooks.cc
@@ -38,6 +38,10 @@ along with GCC; see the file COPYING3. If not see
#include "stor-layout.h"
#include "cgraph.h"
#include "debug.h"
+#include "function.h"
+#include "basic-block.h"
+#include "gimple.h"
+#include "lto-streamer.h"
/* Do nothing; in many cases the default hook. */
@@ -817,6 +821,19 @@ lhd_begin_section (const char *name)
{
section *section;
+ if (flag_bypass_asm)
+{
+ static int initialized = false;
+ if (!initialized)
+ {
+ gcc_assert (asm_out_file == NULL);
+ lto_set_current_out_file (lto_obj_file_open (asm_file_name,
true));
+ initialized = true;
+ }
+ lto_obj_begin_section (name);
+ return;
+}
+
/* Save the old section so we can restore it in lto_end_asm_section. */
gcc_assert (!saved_section);
saved
[PATCH] lto: bypass-asm: Fixed test(U*) used but never defined error.
>From 5151cf943987347edbc3707f08f0da8cd9f49f88 Mon Sep 17 00:00:00 2001 From: Rishi Raj Date: Fri, 7 Jul 2023 10:15:57 +0530 Subject: [PATCH] lto: Fixed test(U*) used but never defined error. This Patch fixes the error during bootstrapped build. Signed-off-by: Rishi Raj --- gcc/lto-object.cc | 1 + gcc/lto/lto-lang.cc | 1 + 2 files changed, 2 insertions(+) diff --git a/gcc/lto-object.cc b/gcc/lto-object.cc index 33eca5a7d81..097c81a686e 100644 --- a/gcc/lto-object.cc +++ b/gcc/lto-object.cc @@ -31,6 +31,7 @@ along with GCC; see the file COPYING3. If not see #include "gimple.h" #include "diagnostic-core.h" #include "tm.h" +#include "cgraph.h" #include "lto-streamer.h" #include "lto-section-names.h" #include "simple-object.h" diff --git a/gcc/lto/lto-lang.cc b/gcc/lto/lto-lang.cc index cf33bf178c2..35f60325c80 100644 --- a/gcc/lto/lto-lang.cc +++ b/gcc/lto/lto-lang.cc @@ -26,6 +26,7 @@ along with GCC; see the file COPYING3. If not see #include "basic-block.h" #include "tree.h" #include "gimple.h" +#include "cgraph.h" #include "stringpool.h" #include "diagnostic-core.h" #include "stor-layout.h" -- 2.40.1
