Add struct to record dwarf line number state machine.
authorDoug Evans <dje@google.com>
Wed, 27 May 2015 21:44:29 +0000 (14:44 -0700)
committerDoug Evans <dje@google.com>
Wed, 27 May 2015 21:44:29 +0000 (14:44 -0700)
gdb/ChangeLog:

* dwarf2read.c (lnp_state_machine): New typedef.
(lnp_reader_state): New typedef.
(dwarf_record_line_1): Renamed from dwarf_record_line.
All callers updated.
(dwarf_record_line): New function.
(init_lnp_state_machine): New function.
(check_line_address): Replace p_record_line parameter with state.
All callers updated.
(dwarf_decode_lines_1): Call dwarf_record_line, init_lnp_state_machine.
Update to record state in lnp_state_machine.

gdb/ChangeLog
gdb/dwarf2read.c

index d50bb0f..971187f 100644 (file)
@@ -1,5 +1,18 @@
 2015-05-27  Doug Evans  <dje@google.com>
 
+       * dwarf2read.c (lnp_state_machine): New typedef.
+       (lnp_reader_state): New typedef.
+       (dwarf_record_line_1): Renamed from dwarf_record_line.
+       All callers updated.
+       (dwarf_record_line): New function.
+       (init_lnp_state_machine): New function.
+       (check_line_address): Replace p_record_line parameter with state.
+       All callers updated.
+       (dwarf_decode_lines_1): Call dwarf_record_line, init_lnp_state_machine.
+       Update to record state in lnp_state_machine.
+
+2015-05-27  Doug Evans  <dje@google.com>
+
        * dwarf2read.c (record_line_ftype): New typedef.
        (check_line_address): New function.
        (dwarf_decode_lines_1): Call it.
index 0a7950f..1ce616a 100644 (file)
@@ -17480,6 +17480,54 @@ psymtab_include_file_name (const struct line_header *lh, int file_index,
 typedef void (record_line_ftype) (struct subfile *subfile, int line,
                                  CORE_ADDR pc);
 
+/* State machine to track the state of the line number program.  */
+
+typedef struct
+{
+  /* These are part of the standard DWARF line number state machine.  */
+
+  unsigned char op_index;
+  unsigned int file;
+  unsigned int line;
+  CORE_ADDR address;
+  int is_stmt;
+  unsigned int discriminator;
+
+  /* Additional bits of state we need to track.  */
+
+  /* The last file that we called dwarf2_start_subfile for.
+     This is only used for TLLs.  */
+  unsigned int last_file;
+  /* The last file a line number was recorded for.  */
+  struct subfile *last_subfile;
+
+  /* The function to call to record a line.  */
+  record_line_ftype *record_line;
+
+  /* The last line number that was recorded, used to coalesce
+     consecutive entries for the same line.  This can happen, for
+     example, when discriminators are present.  PR 17276.  */
+  unsigned int last_line;
+  int line_has_non_zero_discriminator;
+} lnp_state_machine;
+
+/* There's a lot of static state to pass to dwarf_record_line.
+   This keeps it all together.  */
+
+typedef struct
+{
+  /* The gdbarch.  */
+  struct gdbarch *gdbarch;
+
+  /* The line number header.  */
+  struct line_header *line_header;
+
+  /* Non-zero if we're recording lines.
+     Otherwise we're building partial symtabs and are just interested in
+     finding include files mentioned by the line number program.  */
+  int record_lines_p;
+} lnp_reader_state;
+
 /* Ignore this record_line request.  */
 
 static void
@@ -17539,9 +17587,9 @@ dwarf_record_line_p (unsigned int line, unsigned int last_line,
    in the line table of subfile SUBFILE.  */
 
 static void
-dwarf_record_line (struct gdbarch *gdbarch, struct subfile *subfile,
-                  unsigned int line, CORE_ADDR address,
-                  record_line_ftype p_record_line)
+dwarf_record_line_1 (struct gdbarch *gdbarch, struct subfile *subfile,
+                    unsigned int line, CORE_ADDR address,
+                    record_line_ftype p_record_line)
 {
   CORE_ADDR addr = gdbarch_addr_bits_remove (gdbarch, address);
 
@@ -17558,7 +17606,7 @@ dwarf_record_line (struct gdbarch *gdbarch, struct subfile *subfile,
 
 /* Subroutine of dwarf_decode_lines_1 to simplify it.
    Mark the end of a set of line number records.
-   The arguments are the same as for dwarf_record_line.
+   The arguments are the same as for dwarf_record_line_1.
    If SUBFILE is NULL the request is ignored.  */
 
 static void
@@ -17576,14 +17624,103 @@ dwarf_finish_line (struct gdbarch *gdbarch, struct subfile *subfile,
                          paddress (gdbarch, address));
     }
 
-  dwarf_record_line (gdbarch, subfile, 0, address, p_record_line);
+  dwarf_record_line_1 (gdbarch, subfile, 0, address, p_record_line);
+}
+
+/* Record the line in STATE.
+   END_SEQUENCE is non-zero if we're processing the end of a sequence.  */
+
+static void
+dwarf_record_line (lnp_reader_state *reader, lnp_state_machine *state,
+                  int end_sequence)
+{
+  const struct line_header *lh = reader->line_header;
+  unsigned int file, line, discriminator;
+  int is_stmt;
+
+  file = state->file;
+  line = state->line;
+  is_stmt = state->is_stmt;
+  discriminator = state->discriminator;
+
+  if (dwarf_line_debug)
+    {
+      fprintf_unfiltered (gdb_stdlog,
+                         "Processing actual line %u: file %u,"
+                         " address %s, is_stmt %u, discrim %u\n",
+                         line, file,
+                         paddress (reader->gdbarch, state->address),
+                         is_stmt, discriminator);
+    }
+
+  if (file == 0 || file - 1 >= lh->num_file_names)
+    dwarf2_debug_line_missing_file_complaint ();
+  /* For now we ignore lines not starting on an instruction boundary.
+     But not when processing end_sequence for compatibility with the
+     previous version of the code.  */
+  else if (state->op_index == 0 || end_sequence)
+    {
+      lh->file_names[file - 1].included_p = 1;
+      if (reader->record_lines_p && is_stmt)
+       {
+         if (state->last_subfile != current_subfile)
+           {
+             dwarf_finish_line (reader->gdbarch, state->last_subfile,
+                                state->address, state->record_line);
+           }
+
+         if (!end_sequence)
+           {
+             if (dwarf_record_line_p (line, state->last_line,
+                                      state->line_has_non_zero_discriminator,
+                                      state->last_subfile))
+               {
+                 dwarf_record_line_1 (reader->gdbarch, current_subfile,
+                                      line, state->address,
+                                      state->record_line);
+               }
+             state->last_subfile = current_subfile;
+             state->last_line = line;
+           }
+       }
+    }
+}
+
+/* Initialize STATE for the start of a line number program.  */
+
+static void
+init_lnp_state_machine (lnp_state_machine *state,
+                       const lnp_reader_state *reader)
+{
+  memset (state, 0, sizeof (*state));
+
+  /* Just starting, there is no "last file".  */
+  state->last_file = 0;
+  state->last_subfile = NULL;
+
+  state->record_line = record_line;
+
+  state->last_line = 0;
+  state->line_has_non_zero_discriminator = 0;
+
+  /* Initialize these according to the DWARF spec.  */
+  state->op_index = 0;
+  state->file = 1;
+  state->line = 1;
+  /* Call `gdbarch_adjust_dwarf2_line' on the initial 0 address as if there
+     was a line entry for it so that the backend has a chance to adjust it
+     and also record it in case it needs it.  This is currently used by MIPS
+     code, cf. `mips_adjust_dwarf2_line'.  */
+  state->address = gdbarch_adjust_dwarf2_line (reader->gdbarch, 0, 0);
+  state->is_stmt = reader->line_header->default_is_stmt;
+  state->discriminator = 0;
 }
 
 /* Check address and if invalid nop-out the rest of the lines in this
    sequence.  */
 
 static void
-check_line_address (struct dwarf2_cu *cu, record_line_ftype **p_record_line,
+check_line_address (struct dwarf2_cu *cu, lnp_state_machine *state,
                    const gdb_byte *line_ptr,
                    CORE_ADDR lowpc, CORE_ADDR address)
 {
@@ -17603,14 +17740,16 @@ check_line_address (struct dwarf2_cu *cu, record_line_ftype **p_record_line,
       complaint (&symfile_complaints,
                 _(".debug_line address at offset 0x%lx is 0 [in module %s]"),
                 line_offset, objfile_name (objfile));
-      *p_record_line = noop_record_line;
-      /* Note: *p_record_line is left as noop_record_line
+      state->record_line = noop_record_line;
+      /* Note: sm.record_line is left as noop_record_line
         until we see DW_LNE_end_sequence.  */
     }
 }
 
 /* Subroutine of dwarf_decode_lines to simplify it.
-   Process the line number information in LH.  */
+   Process the line number information in LH.
+   If DECODE_FOR_PST_P is non-zero, all we do is process the line number
+   program in order to set included_p for every referenced header.  */
 
 static void
 dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
@@ -17624,43 +17763,38 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
   struct objfile *objfile = cu->objfile;
   bfd *abfd = objfile->obfd;
   struct gdbarch *gdbarch = get_objfile_arch (objfile);
-  struct subfile *last_subfile = NULL;
-  void (*p_record_line) (struct subfile *subfile, int line, CORE_ADDR pc)
-    = record_line;
+  /* Non-zero if we're recording line info (as opposed to building partial
+     symtabs).  */
+  int record_lines_p = !decode_for_pst_p;
+  /* A collection of things we need to pass to dwarf_record_line.  */
+  lnp_reader_state reader_state;
 
   baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
 
   line_ptr = lh->statement_program_start;
   line_end = lh->statement_program_end;
 
+  reader_state.gdbarch = gdbarch;
+  reader_state.line_header = lh;
+  reader_state.record_lines_p = record_lines_p;
+
   /* Read the statement sequences until there's nothing left.  */
   while (line_ptr < line_end)
     {
-      /* State machine registers.  Call `gdbarch_adjust_dwarf2_line'
-         on the initial 0 address as if there was a line entry for it
-         so that the backend has a chance to adjust it and also record
-         it in case it needs it.  This is currently used by MIPS code,
-         cf. `mips_adjust_dwarf2_line'.  */
-      CORE_ADDR address = gdbarch_adjust_dwarf2_line (gdbarch, 0, 0);
-      unsigned int file = 1;
-      unsigned int line = 1;
-      int is_stmt = lh->default_is_stmt;
+      /* The DWARF line number program state machine.  */
+      lnp_state_machine state_machine;
       int end_sequence = 0;
-      unsigned char op_index = 0;
-      unsigned int discriminator = 0;
-      /* The last line number that was recorded, used to coalesce
-        consecutive entries for the same line.  This can happen, for
-        example, when discriminators are present.  PR 17276.  */
-      unsigned int last_line = 0;
-      int line_has_non_zero_discriminator = 0;
-
-      if (!decode_for_pst_p && lh->num_file_names >= file)
+
+      /* Reset the state machine at the start of each sequence.  */
+      init_lnp_state_machine (&state_machine, &reader_state);
+
+      if (record_lines_p && lh->num_file_names >= state_machine.file)
        {
           /* Start a subfile for the current file of the state machine.  */
          /* lh->include_dirs and lh->file_names are 0-based, but the
             directory and file name numbers in the statement program
             are 1-based.  */
-          struct file_entry *fe = &lh->file_names[file - 1];
+          struct file_entry *fe = &lh->file_names[state_machine.file - 1];
           const char *dir = NULL;
 
           if (fe->dir_index && lh->include_dirs != NULL)
@@ -17670,15 +17804,10 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
        }
 
       /* Decode the table.  */
-      while (!end_sequence)
+      while (line_ptr < line_end && !end_sequence)
        {
          op_code = read_1_byte (abfd, line_ptr);
          line_ptr += 1;
-          if (line_ptr > line_end)
-            {
-              dwarf2_debug_line_missing_end_sequence_complaint ();
-              break;
-            }
 
          if (op_code >= lh->opcode_base)
            {
@@ -17688,42 +17817,23 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
              int line_delta;
 
              adj_opcode = op_code - lh->opcode_base;
-             addr_adj = (((op_index + (adj_opcode / lh->line_range))
+             addr_adj = (((state_machine.op_index
+                           + (adj_opcode / lh->line_range))
                           / lh->maximum_ops_per_instruction)
                          * lh->minimum_instruction_length);
-             address += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
-             op_index = ((op_index + (adj_opcode / lh->line_range))
-                         % lh->maximum_ops_per_instruction);
+             state_machine.address
+               += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
+             state_machine.op_index = ((state_machine.op_index
+                                        + (adj_opcode / lh->line_range))
+                                       % lh->maximum_ops_per_instruction);
              line_delta = lh->line_base + (adj_opcode % lh->line_range);
-             line += line_delta;
+             state_machine.line += line_delta;
              if (line_delta != 0)
-               line_has_non_zero_discriminator = discriminator != 0;
-             if (lh->num_file_names < file || file == 0)
-               dwarf2_debug_line_missing_file_complaint ();
-             /* For now we ignore lines not starting on an
-                instruction boundary.  */
-             else if (op_index == 0)
-               {
-                 lh->file_names[file - 1].included_p = 1;
-                 if (!decode_for_pst_p && is_stmt)
-                   {
-                     if (last_subfile != current_subfile)
-                       {
-                         dwarf_finish_line (gdbarch, last_subfile,
-                                            address, p_record_line);
-                       }
-                     if (dwarf_record_line_p (line, last_line,
-                                              line_has_non_zero_discriminator,
-                                              last_subfile))
-                       {
-                         dwarf_record_line (gdbarch, current_subfile,
-                                            line, address, p_record_line);
-                       }
-                     last_subfile = current_subfile;
-                     last_line = line;
-                   }
-               }
-             discriminator = 0;
+               state_machine.line_has_non_zero_discriminator
+                 = state_machine.discriminator != 0;
+
+             dwarf_record_line (&reader_state, &state_machine, 0);
+             state_machine.discriminator = 0;
            }
          else switch (op_code)
            {
@@ -17737,17 +17847,22 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
              switch (extended_op)
                {
                case DW_LNE_end_sequence:
-                 p_record_line = record_line;
+                 state_machine.record_line = record_line;
                  end_sequence = 1;
                  break;
                case DW_LNE_set_address:
-                 address = read_address (abfd, line_ptr, cu, &bytes_read);
-                 line_ptr += bytes_read;
-                 check_line_address (cu, &p_record_line, line_ptr,
-                                     lowpc, address);
-                 op_index = 0;
-                 address += baseaddr;
-                 address = gdbarch_adjust_dwarf2_line (gdbarch, address, 0);
+                 {
+                   CORE_ADDR address
+                     = read_address (abfd, line_ptr, cu, &bytes_read);
+
+                   line_ptr += bytes_read;
+                   check_line_address (cu, &state_machine, line_ptr,
+                                       lowpc, address);
+                   state_machine.op_index = 0;
+                   address += baseaddr;
+                   state_machine.address
+                     = gdbarch_adjust_dwarf2_line (gdbarch, address, 0);
+                 }
                  break;
                case DW_LNE_define_file:
                   {
@@ -17775,9 +17890,10 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
                     if there are consecutive entries for the same
                     (non-prologue) line we want to coalesce them.
                     PR 17276.  */
-                 discriminator = read_unsigned_leb128 (abfd, line_ptr,
-                                                       &bytes_read);
-                 line_has_non_zero_discriminator |= discriminator != 0;
+                 state_machine.discriminator
+                   = read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
+                 state_machine.line_has_non_zero_discriminator
+                   |= state_machine.discriminator != 0;
                  line_ptr += bytes_read;
                  break;
                default:
@@ -17796,30 +17912,8 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
                }
              break;
            case DW_LNS_copy:
-             if (lh->num_file_names < file || file == 0)
-               dwarf2_debug_line_missing_file_complaint ();
-             else
-               {
-                 lh->file_names[file - 1].included_p = 1;
-                 if (!decode_for_pst_p && is_stmt)
-                   {
-                     if (last_subfile != current_subfile)
-                       {
-                         dwarf_finish_line (gdbarch, last_subfile,
-                                            address, p_record_line);
-                       }
-                     if (dwarf_record_line_p (line, last_line,
-                                              line_has_non_zero_discriminator,
-                                              last_subfile))
-                       {
-                         dwarf_record_line (gdbarch, current_subfile,
-                                            line, address, p_record_line);
-                       }
-                     last_subfile = current_subfile;
-                     last_line = line;
-                   }
-               }
-             discriminator = 0;
+             dwarf_record_line (&reader_state, &state_machine, 0);
+             state_machine.discriminator = 0;
              break;
            case DW_LNS_advance_pc:
              {
@@ -17827,12 +17921,13 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
                  = read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
                CORE_ADDR addr_adj;
 
-               addr_adj = (((op_index + adjust)
+               addr_adj = (((state_machine.op_index + adjust)
                             / lh->maximum_ops_per_instruction)
                            * lh->minimum_instruction_length);
-               address += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
-               op_index = ((op_index + adjust)
-                           % lh->maximum_ops_per_instruction);
+               state_machine.address
+                 += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
+               state_machine.op_index = ((state_machine.op_index + adjust)
+                                         % lh->maximum_ops_per_instruction);
                line_ptr += bytes_read;
              }
              break;
@@ -17841,44 +17936,48 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
                int line_delta
                  = read_signed_leb128 (abfd, line_ptr, &bytes_read);
 
-               line += line_delta;
+               state_machine.line += line_delta;
                if (line_delta != 0)
-                 line_has_non_zero_discriminator = discriminator != 0;
+                 state_machine.line_has_non_zero_discriminator
+                   = state_machine.discriminator != 0;
                line_ptr += bytes_read;
              }
              break;
            case DW_LNS_set_file:
-              {
-                /* The arrays lh->include_dirs and lh->file_names are
-                   0-based, but the directory and file name numbers in
-                   the statement program are 1-based.  */
-                struct file_entry *fe;
-                const char *dir = NULL;
-
-                file = read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
-                line_ptr += bytes_read;
-                if (lh->num_file_names < file || file == 0)
-                  dwarf2_debug_line_missing_file_complaint ();
-                else
-                  {
-                    fe = &lh->file_names[file - 1];
-                    if (fe->dir_index && lh->include_dirs != NULL)
-                      dir = lh->include_dirs[fe->dir_index - 1];
-                    if (!decode_for_pst_p)
-                      {
-                        last_subfile = current_subfile;
-                       line_has_non_zero_discriminator = discriminator != 0;
-                        dwarf2_start_subfile (fe->name, dir);
-                      }
-                  }
-              }
+             {
+               /* The arrays lh->include_dirs and lh->file_names are
+                  0-based, but the directory and file name numbers in
+                  the statement program are 1-based.  */
+               struct file_entry *fe;
+               const char *dir = NULL;
+
+               state_machine.file = read_unsigned_leb128 (abfd, line_ptr,
+                                                          &bytes_read);
+               line_ptr += bytes_read;
+               if (state_machine.file == 0
+                   || state_machine.file - 1 >= lh->num_file_names)
+                 dwarf2_debug_line_missing_file_complaint ();
+               else
+                 {
+                   fe = &lh->file_names[state_machine.file - 1];
+                   if (fe->dir_index && lh->include_dirs != NULL)
+                     dir = lh->include_dirs[fe->dir_index - 1];
+                   if (record_lines_p)
+                     {
+                       state_machine.last_subfile = current_subfile;
+                       state_machine.line_has_non_zero_discriminator
+                         = state_machine.discriminator != 0;
+                       dwarf2_start_subfile (fe->name, dir);
+                     }
+                 }
+             }
              break;
            case DW_LNS_set_column:
              (void) read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
              line_ptr += bytes_read;
              break;
            case DW_LNS_negate_stmt:
-             is_stmt = (!is_stmt);
+             state_machine.is_stmt = (!state_machine.is_stmt);
              break;
            case DW_LNS_set_basic_block:
              break;
@@ -17892,12 +17991,13 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
                CORE_ADDR adjust = (255 - lh->opcode_base) / lh->line_range;
                CORE_ADDR addr_adj;
 
-               addr_adj = (((op_index + adjust)
+               addr_adj = (((state_machine.op_index + adjust)
                             / lh->maximum_ops_per_instruction)
                            * lh->minimum_instruction_length);
-               address += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
-               op_index = ((op_index + adjust)
-                           % lh->maximum_ops_per_instruction);
+               state_machine.address
+                 += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
+               state_machine.op_index = ((state_machine.op_index + adjust)
+                                         % lh->maximum_ops_per_instruction);
              }
              break;
            case DW_LNS_fixed_advance_pc:
@@ -17905,8 +18005,9 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
                CORE_ADDR addr_adj;
 
                addr_adj = read_2_bytes (abfd, line_ptr);
-               address += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
-               op_index = 0;
+               state_machine.address
+                 += gdbarch_adjust_dwarf2_line (gdbarch, addr_adj, 1);
+               state_machine.op_index = 0;
                line_ptr += 2;
              }
              break;
@@ -17923,17 +18024,13 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
              }
            }
        }
-      if (lh->num_file_names < file || file == 0)
-        dwarf2_debug_line_missing_file_complaint ();
-      else
-        {
-          lh->file_names[file - 1].included_p = 1;
-          if (!decode_for_pst_p)
-           {
-             dwarf_finish_line (gdbarch, current_subfile, address,
-                                p_record_line);
-           }
-        }
+
+      if (!end_sequence)
+       dwarf2_debug_line_missing_end_sequence_complaint ();
+
+      /* We got a DW_LNE_end_sequence (or we ran off the end of the buffer,
+        in which case we still finish recording the last line).  */
+      dwarf_record_line (&reader_state, &state_machine, 1);
     }
 }