Re: [7/10] keep track of dependencies

[Tom Tromey <tromey@redhat.com>]

>>>>> "Tom" == Tom Tromey <tromey@redhat.com> writes:

Tom> This patch introduces the dependency-tracking code for psymtabs and
Tom> symtabs.

This patch changed a little while rebasing it on top of the Fission
series.

I'm going to put it into the big final commit, but here it is split out
for easier reading.

Tom

From e63a675d1fa95ec6a12d3f84e31bab2273098204 Mon Sep 17 00:00:00 2001
From: Tom Tromey <tromey@redhat.com>
Date: Tue, 17 Apr 2012 05:20:56 -0600
Subject: [PATCH 07/10] make each partial unit into a psymtab and then a
 symtab

	* dwarf2read.c (struct dwarf2_per_cu_data) <psymtab>: Update
	comment.
	(struct partial_die_info) <locdesc>: Remove.
	<d>: New field.
	(process_psymtab_comp_unit): Add 'read_partial' argument.
	Update.
	(process_type_comp_unit, dwarf2_build_psymtabs_hard): Update.
	(scan_partial_symbols): Handle DW_TAG_imported_unit.
	(add_partial_symbol): Update.
	(process_die): Handle DW_TAG_partial_unit.
	(read_file_scope): Update comment.
	(load_partial_dies): Handle DW_TAG_imported_unit.
	(read_partial_die): Handle DW_TAG_partial_unit, DW_AT_import.
	(determine_prefix, dwarf2_name): Handle DW_TAG_partial_unit.
---
 gdb/dwarf2read.c |   73 ++++++++++++++++++++++++++++++++++++++++--------------
 1 files changed, 54 insertions(+), 19 deletions(-)

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 8964b00..d34c048 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -483,8 +483,7 @@ struct dwarf2_per_cu_data
   union
   {
     /* The partial symbol table associated with this compilation unit,
-       or NULL for partial units (which do not have an associated
-       symtab).  */
+       or NULL for unread partial units.  */
     struct partial_symtab *psymtab;
 
     /* Data needed by the "quick" functions.  */
@@ -695,8 +694,15 @@ struct partial_die_info
        when this compilation unit leaves the cache.  */
     char *scope;
 
-    /* The location description associated with this DIE, if any.  */
-    struct dwarf_block *locdesc;
+    /* Some data associated with the partial DIE.  The tag determines
+       which field is live.  */
+    union
+    {
+      /* The location description associated with this DIE, if any.  */
+      struct dwarf_block *locdesc;
+      /* The offset of an import, for DW_TAG_imported_unit.  */
+      sect_offset offset;
+    } d;
 
     /* If HAS_PC_INFO, the PC range associated with this DIE.  */
     CORE_ADDR lowpc;
@@ -1407,7 +1413,7 @@ static void init_cutu_and_read_dies_simple
 
 static htab_t allocate_signatured_type_table (struct objfile *objfile);
 
-static void process_psymtab_comp_unit (struct dwarf2_per_cu_data *);
+static void process_psymtab_comp_unit (struct dwarf2_per_cu_data *, int);
 
 static htab_t allocate_dwo_unit_table (struct objfile *objfile);
 
@@ -4014,8 +4020,11 @@ process_psymtab_comp_unit_reader (const struct die_reader_specs *reader,
   struct partial_symtab *pst;
   int has_pc_info;
   const char *filename;
+  int *want_partial_unit_ptr = data;
 
-  if (comp_unit_die->tag == DW_TAG_partial_unit)
+  if (comp_unit_die->tag == DW_TAG_partial_unit
+      && (want_partial_unit_ptr == NULL
+	  || !*want_partial_unit_ptr))
     return;
 
   prepare_one_comp_unit (cu, comp_unit_die);
@@ -4117,7 +4126,8 @@ process_psymtab_comp_unit_reader (const struct die_reader_specs *reader,
    Process compilation unit THIS_CU for a psymtab.  */
 
 static void
-process_psymtab_comp_unit (struct dwarf2_per_cu_data *this_cu)
+process_psymtab_comp_unit (struct dwarf2_per_cu_data *this_cu,
+			   int want_partial_unit)
 {
   /* If this compilation unit was already read in, free the
      cached copy in order to read it in again.	This is
@@ -4129,7 +4139,7 @@ process_psymtab_comp_unit (struct dwarf2_per_cu_data *this_cu)
 
   gdb_assert (! this_cu->is_debug_types);
   init_cutu_and_read_dies (this_cu, 0, 0, process_psymtab_comp_unit_reader,
-			   NULL);
+			   &want_partial_unit);
 
   /* Age out any secondary CUs.  */
   age_cached_comp_units ();
@@ -4220,7 +4230,7 @@ dwarf2_build_psymtabs_hard (struct objfile *objfile)
     {
       struct dwarf2_per_cu_data *per_cu = dw2_get_cu (i);
 
-      process_psymtab_comp_unit (per_cu);
+      process_psymtab_comp_unit (per_cu, 0);
     }
 
   objfile->psymtabs_addrmap = addrmap_create_fixed (objfile->psymtabs_addrmap,
@@ -4350,7 +4360,8 @@ scan_partial_symbols (struct partial_die_info *first_die, CORE_ADDR *lowpc,
 	 enums.  */
 
       if (pdi->name != NULL || pdi->tag == DW_TAG_namespace
-	  || pdi->tag == DW_TAG_module || pdi->tag == DW_TAG_enumeration_type)
+	  || pdi->tag == DW_TAG_module || pdi->tag == DW_TAG_enumeration_type
+	  || pdi->tag == DW_TAG_imported_unit)
 	{
 	  switch (pdi->tag)
 	    {
@@ -4390,6 +4401,18 @@ scan_partial_symbols (struct partial_die_info *first_die, CORE_ADDR *lowpc,
 	    case DW_TAG_module:
 	      add_partial_module (pdi, lowpc, highpc, need_pc, cu);
 	      break;
+	    case DW_TAG_imported_unit:
+	      {
+		struct dwarf2_per_cu_data *per_cu;
+
+		per_cu = dwarf2_find_containing_comp_unit (pdi->d.offset,
+							   cu->objfile);
+
+		/* Go read the partial unit, if needed.  */
+		if (per_cu->v.psymtab == NULL)
+		  process_psymtab_comp_unit (per_cu, 1);
+	      }
+	      break;
 	    default:
 	      break;
 	    }
@@ -4598,10 +4621,10 @@ add_partial_symbol (struct partial_die_info *pdi, struct dwarf2_cu *cu)
       }
       break;
     case DW_TAG_variable:
-      if (pdi->locdesc)
-	addr = decode_locdesc (pdi->locdesc, cu);
+      if (pdi->d.locdesc)
+	addr = decode_locdesc (pdi->d.locdesc, cu);
 
-      if (pdi->locdesc
+      if (pdi->d.locdesc
 	  && addr == 0
 	  && !dwarf2_per_objfile->has_section_at_zero)
 	{
@@ -4625,7 +4648,7 @@ add_partial_symbol (struct partial_die_info *pdi, struct dwarf2_cu *cu)
 	     used by GDB, but it comes in handy for debugging partial symbol
 	     table building.  */
 
-	  if (pdi->locdesc || pdi->has_type)
+	  if (pdi->d.locdesc || pdi->has_type)
 	    add_psymbol_to_list (actual_name, strlen (actual_name),
 				 built_actual_name,
 				 VAR_DOMAIN, LOC_STATIC,
@@ -4636,7 +4659,7 @@ add_partial_symbol (struct partial_die_info *pdi, struct dwarf2_cu *cu)
       else
 	{
 	  /* Static Variable.  Skip symbols without location descriptors.  */
-	  if (pdi->locdesc == NULL)
+	  if (pdi->d.locdesc == NULL)
 	    {
 	      if (built_actual_name)
 		xfree (actual_name);
@@ -5484,6 +5507,7 @@ process_die (struct die_info *die, struct dwarf2_cu *cu)
     case DW_TAG_padding:
       break;
     case DW_TAG_compile_unit:
+    case DW_TAG_partial_unit:
       read_file_scope (die, cu);
       break;
     case DW_TAG_type_unit:
@@ -6226,7 +6250,7 @@ handle_DW_AT_stmt_list (struct die_info *die, struct dwarf2_cu *cu,
     }
 }
 
-/* Process DW_TAG_compile_unit.  */
+/* Process DW_TAG_compile_unit or DW_TAG_partial_unit.  */
 
 static void
 read_file_scope (struct die_info *die, struct dwarf2_cu *cu)
@@ -10688,7 +10712,8 @@ load_partial_dies (const struct die_reader_specs *reader,
 	  && abbrev->tag != DW_TAG_variable
 	  && abbrev->tag != DW_TAG_namespace
 	  && abbrev->tag != DW_TAG_module
-	  && abbrev->tag != DW_TAG_member)
+	  && abbrev->tag != DW_TAG_member
+	  && abbrev->tag != DW_TAG_imported_unit)
 	{
 	  /* Otherwise we skip to the next sibling, if any.  */
 	  info_ptr = skip_one_die (reader, info_ptr + bytes_read, abbrev);
@@ -10906,6 +10931,7 @@ read_partial_die (const struct die_reader_specs *reader,
 	  switch (part_die->tag)
 	    {
 	    case DW_TAG_compile_unit:
+	    case DW_TAG_partial_unit:
 	    case DW_TAG_type_unit:
 	      /* Compilation units have a DW_AT_name that is a filename, not
 		 a source language identifier.  */
@@ -10950,7 +10976,7 @@ read_partial_die (const struct die_reader_specs *reader,
           /* Support the .debug_loc offsets.  */
           if (attr_form_is_block (&attr))
             {
-	       part_die->locdesc = DW_BLOCK (&attr);
+	       part_die->d.locdesc = DW_BLOCK (&attr);
             }
           else if (attr_form_is_section_offset (&attr))
             {
@@ -11019,6 +11045,12 @@ read_partial_die (const struct die_reader_specs *reader,
 	      || DW_UNSND (&attr) == DW_INL_declared_inlined)
 	    part_die->may_be_inlined = 1;
 	  break;
+
+	case DW_AT_import:
+	  if (part_die->tag == DW_TAG_imported_unit)
+	    part_die->d.offset = dwarf2_get_ref_die_offset (&attr);
+	  break;
+
 	default:
 	  break;
 	}
@@ -14021,6 +14053,7 @@ determine_prefix (struct die_info *die, struct dwarf2_cu *cu)
 	     So it does not need a prefix.  */
 	  return "";
       case DW_TAG_compile_unit:
+      case DW_TAG_partial_unit:
 	/* gcc-4.5 -gdwarf-4 can drop the enclosing namespace.  Cope.  */
 	if (cu->language == language_cplus
 	    && !VEC_empty (dwarf2_section_info_def, dwarf2_per_objfile->types)
@@ -14141,6 +14174,7 @@ dwarf2_name (struct die_info *die, struct dwarf2_cu *cu)
   switch (die->tag)
     {
     case DW_TAG_compile_unit:
+    case DW_TAG_partial_unit:
       /* Compilation units have a DW_AT_name that is a filename, not
 	 a source language identifier.  */
     case DW_TAG_enumeration_type:
@@ -14174,7 +14208,8 @@ dwarf2_name (struct die_info *die, struct dwarf2_cu *cu)
 	      if (die->tag == DW_TAG_class_type)
 		return dwarf2_name (die, cu);
 	    }
-	  while (die->tag != DW_TAG_compile_unit);
+	  while (die->tag != DW_TAG_compile_unit
+		 && die->tag != DW_TAG_partial_unit);
 	}
       break;
 
-- 
1.7.7.6