[RFC v5 01/18] gdb: introduce expand_symtabs_maybe_overlapping

[Jan Vrany <jan.vrany@labware.com>]

This commit introduces expand_symtabs_maybe_overlapping, a new "quick
symbol function".  This will be used later by Python API to create new
compunits to ensure to-be-created compunit does not overlap with
existing one.

For DWARF2 base index functions, all compunits are expanded
unconditionally since there seem to be no way to extract unexpanded
compunit's conservative address range.
---
 gdb/dwarf2/cooked-index.h | 11 +++++++++++
 gdb/dwarf2/read.c         | 11 +++++++++++
 gdb/dwarf2/read.h         |  3 +++
 gdb/objfiles.h            |  3 +++
 gdb/psymtab.c             | 21 +++++++++++++++++++++
 gdb/psymtab.h             |  3 +++
 gdb/quick-symbol.h        |  5 +++++
 gdb/symfile-debug.c       | 16 ++++++++++++++++
 gdbsupport/range.h        | 35 +++++++++++++++++++++++++++++++++++
 9 files changed, 108 insertions(+)
 create mode 100644 gdbsupport/range.h

diff --git a/gdb/dwarf2/cooked-index.h b/gdb/dwarf2/cooked-index.h
index 43b27232aec..894f2078e9f 100644
--- a/gdb/dwarf2/cooked-index.h
+++ b/gdb/dwarf2/cooked-index.h
@@ -237,6 +237,17 @@ struct cooked_index_functions : public dwarf2_base_index_functions
     dwarf2_base_index_functions::expand_all_symtabs (objfile);
   }
 
+  /* Cooked index's version of expand_symtabs_maybe_overlapping.  See its
+     definition in the definition of quick_symbol_functions in symfile.h.  */
+
+  void expand_symtabs_maybe_overlapping (struct objfile *objfile,
+	CORE_ADDR start, CORE_ADDR end) override
+  {
+    wait (objfile, true);
+    dwarf2_base_index_functions::expand_symtabs_maybe_overlapping
+      (objfile, start, end);
+  }
+
   bool expand_symtabs_matching
     (struct objfile *objfile,
      expand_symtabs_file_matcher file_matcher,
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 2f27b7cff4c..3270ce55c56 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -1926,6 +1926,17 @@ dwarf2_base_index_functions::expand_all_symtabs (struct objfile *objfile)
     }
 }
 
+/* DWARF2 index's version of expand_symtabs_maybe_overlapping.  See its definition
+   in the definition of quick_symbol_functions in symfile.h.  */
+
+void
+dwarf2_base_index_functions::expand_symtabs_maybe_overlapping
+  (struct objfile *objfile, CORE_ADDR start, CORE_ADDR end)
+{
+  /* Simply expand all symtabs. I do not know how to extract (if at all
+     possible) conservative address range from dwarf2_per_cu_data.  */
+  expand_all_symtabs (objfile);
+}
 /* See read.h.  */
 
 bool
diff --git a/gdb/dwarf2/read.h b/gdb/dwarf2/read.h
index a5cfb3144f7..da55f993123 100644
--- a/gdb/dwarf2/read.h
+++ b/gdb/dwarf2/read.h
@@ -1192,6 +1192,9 @@ struct dwarf2_base_index_functions : public quick_symbol_functions
 
   void expand_all_symtabs (struct objfile *objfile) override;
 
+  virtual void expand_symtabs_maybe_overlapping (struct objfile *objfile,
+	CORE_ADDR start, CORE_ADDR end) override;
+
   struct compunit_symtab *find_pc_sect_compunit_symtab
     (struct objfile *objfile, bound_minimal_symbol msymbol,
      CORE_ADDR pc, struct obj_section *section, int warn_if_readin)
diff --git a/gdb/objfiles.h b/gdb/objfiles.h
index 4a3475862a9..0206b49e00c 100644
--- a/gdb/objfiles.h
+++ b/gdb/objfiles.h
@@ -597,6 +597,9 @@ struct objfile : intrusive_list_node<objfile>
      code, e.g., DW_TAG_type_unit for dwarf debug info.  */
   void expand_symtabs_with_fullname (const char *fullname);
 
+  /* See quick_symbol_functions.  */
+  void expand_symtabs_maybe_overlapping (CORE_ADDR start, CORE_ADDR end);
+
   /* See quick_symbol_functions.  */
   bool expand_symtabs_matching
     (expand_symtabs_file_matcher file_matcher,
diff --git a/gdb/psymtab.c b/gdb/psymtab.c
index 986ef44f6c7..d40afd5877f 100644
--- a/gdb/psymtab.c
+++ b/gdb/psymtab.c
@@ -36,6 +36,7 @@
 #include <algorithm>
 #include <set>
 #include "gdbsupport/buildargv.h"
+#include "gdbsupport/range.h"
 
 static const struct partial_symbol *lookup_partial_symbol
      (struct objfile *, struct partial_symtab *, const lookup_name_info &,
@@ -731,6 +732,26 @@ psymbol_functions::expand_all_symtabs (struct objfile *objfile)
     psymtab_to_symtab (objfile, psymtab);
 }
 
+/* Psymtab version of expand_symtabs_maybe_overlapping.  See its definition in
+   the definition of quick_symbol_functions in symfile.h.  */
+
+void
+psymbol_functions::expand_symtabs_maybe_overlapping
+  (struct objfile *objfile, CORE_ADDR start, CORE_ADDR end)
+{
+  for (partial_symtab *psymtab : partial_symbols (objfile))
+    {
+      if (psymtab->text_low_valid && psymtab->text_high_valid)
+	{
+	  CORE_ADDR text_low = psymtab->text_low (objfile);
+	  CORE_ADDR text_high = psymtab->text_high (objfile);
+
+	  if (ranges_overlap (start, end, text_low, text_high))
+	    psymtab_to_symtab (objfile, psymtab);
+	}
+    }
+}
+
 /* Psymtab version of map_symbol_filenames.  See its definition in
    the definition of quick_symbol_functions in symfile.h.  */
 
diff --git a/gdb/psymtab.h b/gdb/psymtab.h
index ad0b2ff4234..8a8ea738bbd 100644
--- a/gdb/psymtab.h
+++ b/gdb/psymtab.h
@@ -626,6 +626,9 @@ struct psymbol_functions : public quick_symbol_functions
 
   void expand_all_symtabs (struct objfile *objfile) override;
 
+  virtual void expand_symtabs_maybe_overlapping (struct objfile *objfile,
+	CORE_ADDR start, CORE_ADDR end) override;
+
   bool expand_symtabs_matching
     (struct objfile *objfile,
      expand_symtabs_file_matcher file_matcher,
diff --git a/gdb/quick-symbol.h b/gdb/quick-symbol.h
index 9db1f1860cb..899f2f22239 100644
--- a/gdb/quick-symbol.h
+++ b/gdb/quick-symbol.h
@@ -130,6 +130,11 @@ struct quick_symbol_functions
   /* Read all symbol tables associated with OBJFILE.  */
   virtual void expand_all_symtabs (struct objfile *objfile) = 0;
 
+  /* Read all symbol tables associated with OBJFILE which may overlap
+     with range [START, END).  */
+  virtual void expand_symtabs_maybe_overlapping (struct objfile *objfile,
+	CORE_ADDR start, CORE_ADDR end) = 0;
+
   /* Expand all symbol tables in OBJFILE matching some criteria.
 
      If LANG_MATCHER returns false, expansion of the symbol table may be
diff --git a/gdb/symfile-debug.c b/gdb/symfile-debug.c
index 9c5ce85d26e..900d1bf90e2 100644
--- a/gdb/symfile-debug.c
+++ b/gdb/symfile-debug.c
@@ -343,6 +343,22 @@ objfile::expand_all_symtabs ()
     iter->expand_all_symtabs (this);
 }
 
+/* See objfiles.h.  */
+
+void
+objfile::expand_symtabs_maybe_overlapping (CORE_ADDR start, CORE_ADDR end)
+{
+  if (debug_symfile)
+    gdb_printf (gdb_stdlog,
+		"qf->expand_symtabs_maybe_overlapping (%s, %s, %s)\n",
+		objfile_debug_name (this),
+		hex_string (start),
+		hex_string (end));
+
+  for (const auto &iter : qf)
+    iter->expand_symtabs_maybe_overlapping (this, start, end);
+}
+
 void
 objfile::expand_symtabs_with_fullname (const char *fullname)
 {
diff --git a/gdbsupport/range.h b/gdbsupport/range.h
new file mode 100644
index 00000000000..b665943cfd3
--- /dev/null
+++ b/gdbsupport/range.h
@@ -0,0 +1,35 @@
+/* Copyright (C) 2025-2025 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef GDBSUPPORT_RANGE_H
+#define GDBSUPPORT_RANGE_H
+
+/* Return true if given ranges [AL, AH) and [BL, BH) overlap.  Return false
+   otherwise.  */
+
+template <typename T>
+bool ranges_overlap (T al, T ah, T bl, T bh)
+{
+  static_assert (std::is_integral<T>::value, "Integral type required");
+
+  gdb_assert (al <= ah);
+  gdb_assert (bl <= bh);
+
+  return !(ah <= bl || bh <= al);
+}
+
+#endif /* GDBSUPPORT_RANGE_H */
-- 
2.47.2