[7/8] Remove the objfile backlink from comp_unit

Message ID 20200208152758.29385-8-tom@tromey.com
State New
Headers show
Series
  • Share DWARF frame information across inferiors
Related show

Commit Message

Tom Tromey Feb. 8, 2020, 3:27 p.m.
This removes the objfile backlink from comp_unit.  The only remaining
uses involved fetching the text offset from the objfile.  However,
this is already convenient computed at all the sites that call
execute_cfa_program, and so it can simply be passed in.

gdb/ChangeLog
2020-02-08  Tom Tromey  <tom@tromey.com>

	* dwarf2/frame.c (struct comp_unit) <objfile>: Remove.
	(execute_cfa_program): Add text_offset parameter.
	(execute_cfa_program_test, dwarf2_fetch_cfa_info)
	(dwarf2_frame_cache): Update.
	(dwarf2_build_frame_info): Don't set "objfile" member.

Change-Id: I81b1c82d514dad83b3d00053756a07ef54b19796
---
 gdb/ChangeLog      |  8 ++++++++
 gdb/dwarf2/frame.c | 25 +++++++++++++------------
 2 files changed, 21 insertions(+), 12 deletions(-)

-- 
2.17.2

Comments

Fangrui Song via Gdb-patches Feb. 9, 2020, 11:19 p.m. | #1
On Sat, Feb 8, 2020, 10:28 Tom Tromey <tom@tromey.com> wrote:

> This removes the objfile backlink from comp_unit.  The only remaining

> uses involved fetching the text offset from the objfile.  However,

> this is already convenient computed at all the sites that call

>


convenient -> conveniently, I think?

execute_cfa_program, and so it can simply be passed in.
>

> gdb/ChangeLog

> 2020-02-08  Tom Tromey  <tom@tromey.com>

>

>         * dwarf2/frame.c (struct comp_unit) <objfile>: Remove.

>         (execute_cfa_program): Add text_offset parameter.

>         (execute_cfa_program_test, dwarf2_fetch_cfa_info)

>         (dwarf2_frame_cache): Update.

>         (dwarf2_build_frame_info): Don't set "objfile" member.

>

> Change-Id: I81b1c82d514dad83b3d00053756a07ef54b19796

> ---

>  gdb/ChangeLog      |  8 ++++++++

>  gdb/dwarf2/frame.c | 25 +++++++++++++------------

>  2 files changed, 21 insertions(+), 12 deletions(-)

>

> diff --git a/gdb/dwarf2/frame.c b/gdb/dwarf2/frame.c

> index d4f6165b75c..2c35016e2d9 100644

> --- a/gdb/dwarf2/frame.c

> +++ b/gdb/dwarf2/frame.c

> @@ -139,8 +139,6 @@ struct comp_unit

>    /* Keep the bfd convenient.  */

>    bfd *abfd = nullptr;

>

> -  struct objfile *objfile = nullptr;

> -

>    /* Pointer to the .debug_frame section loaded into memory.  */

>    const gdb_byte *dwarf_frame_buffer = nullptr;

>

> @@ -349,7 +347,8 @@ Not implemented: computing unwound register using

> explicit value operator"));

>  static const gdb_byte *

>  execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,

>                      const gdb_byte *insn_end, struct gdbarch *gdbarch,

> -                    CORE_ADDR pc, struct dwarf2_frame_state *fs)

> +                    CORE_ADDR pc, struct dwarf2_frame_state *fs,

> +                    CORE_ADDR text_offset)

>  {

>    int eh_frame_p = fde->eh_frame_p;

>    unsigned int bytes_read;

> @@ -386,8 +385,8 @@ execute_cfa_program (struct dwarf2_fde *fde, const

> gdb_byte *insn_ptr,

>               fs->pc = read_encoded_value (fde->cie->unit,

> fde->cie->encoding,

>                                            fde->cie->ptr_size, insn_ptr,

>                                            &bytes_read,

> fde->initial_location);

> -             /* Apply the objfile offset for relocatable objects.  */

> -             fs->pc += fde->cie->unit->objfile->text_section_offset ();

> +             /* Apply the text offset for relocatable objects.  */

> +             fs->pc += text_offset;

>               insn_ptr += bytes_read;

>               break;

>

> @@ -646,7 +645,7 @@ execute_cfa_program_test (struct gdbarch *gdbarch)

>

>    const gdb_byte *insn_end = insns + sizeof (insns);

>    const gdb_byte *out = execute_cfa_program (&fde, insns, insn_end,

> gdbarch,

> -                                            0, &fs);

> +                                            0, &fs, 0);

>

>    SELF_CHECK (out == insn_end);

>    SELF_CHECK (fs.pc == 0);

> @@ -894,13 +893,14 @@ dwarf2_fetch_cfa_info (struct gdbarch *gdbarch,

> CORE_ADDR pc,

>

>    /* First decode all the insns in the CIE.  */

>    execute_cfa_program (fde, fde->cie->initial_instructions,

> -                      fde->cie->end, gdbarch, pc, &fs);

> +                      fde->cie->end, gdbarch, pc, &fs, text_offset);

>

>    /* Save the initialized register set.  */

>    fs.initial = fs.regs;

>

>    /* Then decode the insns in the FDE up to our target PC.  */

> -  execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc,

> &fs);

> +  execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs,

> +                      text_offset);

>

>    /* Calculate the CFA.  */

>    switch (fs.regs.cfa_how)

> @@ -1022,7 +1022,8 @@ dwarf2_frame_cache (struct frame_info *this_frame,

> void **this_cache)

>    /* First decode all the insns in the CIE.  */

>    execute_cfa_program (fde, fde->cie->initial_instructions,

>                        fde->cie->end, gdbarch,

> -                      get_frame_address_in_block (this_frame), &fs);

> +                      get_frame_address_in_block (this_frame), &fs,

> +                      cache->text_offset);

>

>    /* Save the initialized register set.  */

>    fs.initial = fs.regs;

> @@ -1037,7 +1038,7 @@ dwarf2_frame_cache (struct frame_info *this_frame,

> void **this_cache)

>      {

>        /* Decode the insns in the FDE up to the entry PC.  */

>        instr = execute_cfa_program (fde, fde->instructions, fde->end,

> gdbarch,

> -                                  entry_pc, &fs);

> +                                  entry_pc, &fs, cache->text_offset);

>

>        if (fs.regs.cfa_how == CFA_REG_OFFSET

>           && (dwarf_reg_to_regnum (gdbarch, fs.regs.cfa_reg)

> @@ -1052,7 +1053,8 @@ dwarf2_frame_cache (struct frame_info *this_frame,

> void **this_cache)

>

>    /* Then decode the insns in the FDE up to our target PC.  */

>    execute_cfa_program (fde, instr, fde->end, gdbarch,

> -                      get_frame_address_in_block (this_frame), &fs);

> +                      get_frame_address_in_block (this_frame), &fs,

> +                      cache->text_offset);

>

>    try

>      {

> @@ -2135,7 +2137,6 @@ dwarf2_build_frame_info (struct objfile *objfile)

>    /* Build a minimal decoding of the DWARF2 compilation unit.  */

>    unit = new comp_unit;

>    unit->abfd = objfile->obfd;

> -  unit->objfile = objfile;

>

>    if (objfile->separate_debug_objfile_backlink == NULL)

>      {

> --

> 2.17.2

>

>
Luis Machado Feb. 11, 2020, 10:40 a.m. | #2
On 2/8/20 12:27 PM, Tom Tromey wrote:
> This removes the objfile backlink from comp_unit.  The only remaining

> uses involved fetching the text offset from the objfile.  However,

> this is already convenient computed at all the sites that call

> execute_cfa_program, and so it can simply be passed in.

> 

> gdb/ChangeLog

> 2020-02-08  Tom Tromey  <tom@tromey.com>

> 

> 	* dwarf2/frame.c (struct comp_unit) <objfile>: Remove.

> 	(execute_cfa_program): Add text_offset parameter.

> 	(execute_cfa_program_test, dwarf2_fetch_cfa_info)

> 	(dwarf2_frame_cache): Update.

> 	(dwarf2_build_frame_info): Don't set "objfile" member.

> 

> Change-Id: I81b1c82d514dad83b3d00053756a07ef54b19796

> ---

>   gdb/ChangeLog      |  8 ++++++++

>   gdb/dwarf2/frame.c | 25 +++++++++++++------------

>   2 files changed, 21 insertions(+), 12 deletions(-)

> 

> diff --git a/gdb/dwarf2/frame.c b/gdb/dwarf2/frame.c

> index d4f6165b75c..2c35016e2d9 100644

> --- a/gdb/dwarf2/frame.c

> +++ b/gdb/dwarf2/frame.c

> @@ -139,8 +139,6 @@ struct comp_unit

>     /* Keep the bfd convenient.  */

>     bfd *abfd = nullptr;

>   

> -  struct objfile *objfile = nullptr;

> -

>     /* Pointer to the .debug_frame section loaded into memory.  */

>     const gdb_byte *dwarf_frame_buffer = nullptr;

>   

> @@ -349,7 +347,8 @@ Not implemented: computing unwound register using explicit value operator"));

>   static const gdb_byte *

>   execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,

>   		     const gdb_byte *insn_end, struct gdbarch *gdbarch,

> -		     CORE_ADDR pc, struct dwarf2_frame_state *fs)

> +		     CORE_ADDR pc, struct dwarf2_frame_state *fs,

> +		     CORE_ADDR text_offset)

>   {

>     int eh_frame_p = fde->eh_frame_p;

>     unsigned int bytes_read;

> @@ -386,8 +385,8 @@ execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,

>   	      fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,

>   					   fde->cie->ptr_size, insn_ptr,

>   					   &bytes_read, fde->initial_location);

> -	      /* Apply the objfile offset for relocatable objects.  */

> -	      fs->pc += fde->cie->unit->objfile->text_section_offset ();

> +	      /* Apply the text offset for relocatable objects.  */

> +	      fs->pc += text_offset;

>   	      insn_ptr += bytes_read;

>   	      break;

>   

> @@ -646,7 +645,7 @@ execute_cfa_program_test (struct gdbarch *gdbarch)

>   

>     const gdb_byte *insn_end = insns + sizeof (insns);

>     const gdb_byte *out = execute_cfa_program (&fde, insns, insn_end, gdbarch,

> -					     0, &fs);

> +					     0, &fs, 0);

>   

>     SELF_CHECK (out == insn_end);

>     SELF_CHECK (fs.pc == 0);

> @@ -894,13 +893,14 @@ dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc,

>   

>     /* First decode all the insns in the CIE.  */

>     execute_cfa_program (fde, fde->cie->initial_instructions,

> -		       fde->cie->end, gdbarch, pc, &fs);

> +		       fde->cie->end, gdbarch, pc, &fs, text_offset);

>   

>     /* Save the initialized register set.  */

>     fs.initial = fs.regs;

>   

>     /* Then decode the insns in the FDE up to our target PC.  */

> -  execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs);

> +  execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs,

> +		       text_offset);

>   

>     /* Calculate the CFA.  */

>     switch (fs.regs.cfa_how)

> @@ -1022,7 +1022,8 @@ dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)

>     /* First decode all the insns in the CIE.  */

>     execute_cfa_program (fde, fde->cie->initial_instructions,

>   		       fde->cie->end, gdbarch,

> -		       get_frame_address_in_block (this_frame), &fs);

> +		       get_frame_address_in_block (this_frame), &fs,

> +		       cache->text_offset);

>   

>     /* Save the initialized register set.  */

>     fs.initial = fs.regs;

> @@ -1037,7 +1038,7 @@ dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)

>       {

>         /* Decode the insns in the FDE up to the entry PC.  */

>         instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch,

> -				   entry_pc, &fs);

> +				   entry_pc, &fs, cache->text_offset);

>   

>         if (fs.regs.cfa_how == CFA_REG_OFFSET

>   	  && (dwarf_reg_to_regnum (gdbarch, fs.regs.cfa_reg)

> @@ -1052,7 +1053,8 @@ dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)

>   

>     /* Then decode the insns in the FDE up to our target PC.  */

>     execute_cfa_program (fde, instr, fde->end, gdbarch,

> -		       get_frame_address_in_block (this_frame), &fs);

> +		       get_frame_address_in_block (this_frame), &fs,

> +		       cache->text_offset);

>   

>     try

>       {

> @@ -2135,7 +2137,6 @@ dwarf2_build_frame_info (struct objfile *objfile)

>     /* Build a minimal decoding of the DWARF2 compilation unit.  */

>     unit = new comp_unit;

>     unit->abfd = objfile->obfd;

> -  unit->objfile = objfile;

>   

>     if (objfile->separate_debug_objfile_backlink == NULL)

>       {

> 


LGTM
Tom Tromey Feb. 12, 2020, 12:26 a.m. | #3
>>>>> "Christian" == Christian Biesinger <cbiesinger@google.com> writes:


> On Sat, Feb 8, 2020, 10:28 Tom Tromey <tom@tromey.com> wrote:

>  This removes the objfile backlink from comp_unit.  The only remaining

>  uses involved fetching the text offset from the objfile.  However,

>  this is already convenient computed at all the sites that call


Christian> convenient -> conveniently, I think?

Thanks, I fixed this.

Tom

Patch

diff --git a/gdb/dwarf2/frame.c b/gdb/dwarf2/frame.c
index d4f6165b75c..2c35016e2d9 100644
--- a/gdb/dwarf2/frame.c
+++ b/gdb/dwarf2/frame.c
@@ -139,8 +139,6 @@  struct comp_unit
   /* Keep the bfd convenient.  */
   bfd *abfd = nullptr;
 
-  struct objfile *objfile = nullptr;
-
   /* Pointer to the .debug_frame section loaded into memory.  */
   const gdb_byte *dwarf_frame_buffer = nullptr;
 
@@ -349,7 +347,8 @@  Not implemented: computing unwound register using explicit value operator"));
 static const gdb_byte *
 execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
 		     const gdb_byte *insn_end, struct gdbarch *gdbarch,
-		     CORE_ADDR pc, struct dwarf2_frame_state *fs)
+		     CORE_ADDR pc, struct dwarf2_frame_state *fs,
+		     CORE_ADDR text_offset)
 {
   int eh_frame_p = fde->eh_frame_p;
   unsigned int bytes_read;
@@ -386,8 +385,8 @@  execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
 	      fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
 					   fde->cie->ptr_size, insn_ptr,
 					   &bytes_read, fde->initial_location);
-	      /* Apply the objfile offset for relocatable objects.  */
-	      fs->pc += fde->cie->unit->objfile->text_section_offset ();
+	      /* Apply the text offset for relocatable objects.  */
+	      fs->pc += text_offset;
 	      insn_ptr += bytes_read;
 	      break;
 
@@ -646,7 +645,7 @@  execute_cfa_program_test (struct gdbarch *gdbarch)
 
   const gdb_byte *insn_end = insns + sizeof (insns);
   const gdb_byte *out = execute_cfa_program (&fde, insns, insn_end, gdbarch,
-					     0, &fs);
+					     0, &fs, 0);
 
   SELF_CHECK (out == insn_end);
   SELF_CHECK (fs.pc == 0);
@@ -894,13 +893,14 @@  dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc,
 
   /* First decode all the insns in the CIE.  */
   execute_cfa_program (fde, fde->cie->initial_instructions,
-		       fde->cie->end, gdbarch, pc, &fs);
+		       fde->cie->end, gdbarch, pc, &fs, text_offset);
 
   /* Save the initialized register set.  */
   fs.initial = fs.regs;
 
   /* Then decode the insns in the FDE up to our target PC.  */
-  execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs);
+  execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs,
+		       text_offset);
 
   /* Calculate the CFA.  */
   switch (fs.regs.cfa_how)
@@ -1022,7 +1022,8 @@  dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
   /* First decode all the insns in the CIE.  */
   execute_cfa_program (fde, fde->cie->initial_instructions,
 		       fde->cie->end, gdbarch,
-		       get_frame_address_in_block (this_frame), &fs);
+		       get_frame_address_in_block (this_frame), &fs,
+		       cache->text_offset);
 
   /* Save the initialized register set.  */
   fs.initial = fs.regs;
@@ -1037,7 +1038,7 @@  dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
     {
       /* Decode the insns in the FDE up to the entry PC.  */
       instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch,
-				   entry_pc, &fs);
+				   entry_pc, &fs, cache->text_offset);
 
       if (fs.regs.cfa_how == CFA_REG_OFFSET
 	  && (dwarf_reg_to_regnum (gdbarch, fs.regs.cfa_reg)
@@ -1052,7 +1053,8 @@  dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
 
   /* Then decode the insns in the FDE up to our target PC.  */
   execute_cfa_program (fde, instr, fde->end, gdbarch,
-		       get_frame_address_in_block (this_frame), &fs);
+		       get_frame_address_in_block (this_frame), &fs,
+		       cache->text_offset);
 
   try
     {
@@ -2135,7 +2137,6 @@  dwarf2_build_frame_info (struct objfile *objfile)
   /* Build a minimal decoding of the DWARF2 compilation unit.  */
   unit = new comp_unit;
   unit->abfd = objfile->obfd;
-  unit->objfile = objfile;
 
   if (objfile->separate_debug_objfile_backlink == NULL)
     {