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[deliverable/binutils-gdb.git] / gdb / psymtab.h

diff --git a/gdb/psymtab.h b/gdb/psymtab.h
index 895f950a4665e7afa482b7258da1925765d661d7..3ee5eee0b659522aef70f9af6b443027f2788e67 100644 (file)
--- a/gdb/psymtab.h
+++ b/gdb/psymtab.h
@@ -20,6 +20,7 @@
 #ifndef PSYMTAB_H
 #define PSYMTAB_H
 
+#include "gdb_obstack.h"
 #include "symfile.h"
 #include "common/next-iterator.h"
 
@@ -30,13 +31,26 @@ struct partial_symbol;
 struct psymbol_bcache;
 
 /* An instance of this class manages the partial symbol tables and
-   partial symbols for a given objfile.  */
+   partial symbols for a given objfile.
+
+   The core psymtab functions -- those in psymtab.c -- arrange for
+   nearly all psymtab- and psymbol-related allocations to happen
+   either in the psymtab_storage object (either on its obstack or in
+   other memory managed by this class), or on the per-BFD object.  The
+   only link from the psymtab storage object back to the objfile (or
+   objfile_obstack) that is made by the core psymtab code is the
+   compunit_symtab member in the psymtab.
+
+   However, it is up to each symbol reader to maintain this invariant
+   in other ways, if it wants to reuse psymtabs across multiple
+   objfiles.  The main issue here is ensuring that read_symtab_private
+   does not point into objfile_obstack.  */
 
 class psymtab_storage
 {
 public:
 
-  explicit psymtab_storage (struct objfile *objfile);
+  psymtab_storage ();
 
   ~psymtab_storage ();
 
@@ -55,6 +69,39 @@ public:
 
   void discard_psymtab (struct partial_symtab *pst);
 
+  /* Return the obstack that is used for storage by this object.  */
+
+  struct obstack *obstack ()
+  {
+    if (!m_obstack.has_value ())
+      m_obstack.emplace ();
+    return &*m_obstack;
+  }
+
+  /* Allocate storage for the "dependencies" field of a psymtab.
+     NUMBER says how many dependencies there are.  */
+
+  struct partial_symtab **allocate_dependencies (int number)
+  {
+    return OBSTACK_CALLOC (obstack (), number, struct partial_symtab *);
+  }
+
+  /* Allocate a new psymtab on the psymtab obstack.  The new psymtab
+     will be linked in to the "psymtabs" list, but otherwise all other
+     fields will be zero.  */
+
+  struct partial_symtab *allocate_psymtab ();
+
+  typedef next_adapter<struct partial_symtab> partial_symtab_range;
+
+  /* A range adapter that makes it possible to iterate over all
+     psymtabs in one objfile.  */
+
+  partial_symtab_range range ()
+  {
+    return partial_symtab_range (psymtabs);
+  }
+
 
   /* Each objfile points to a linked list of partial symtabs derived from
      this file, one partial symtab structure for each compilation unit
@@ -69,14 +116,6 @@ public:
 
   struct addrmap *psymtabs_addrmap = nullptr;
 
-  /* List of freed partial symtabs, available for re-use.  */
-
-  struct partial_symtab *free_psymtabs = nullptr;
-
-  /* The obstack where allocations are made.  */
-
-  struct obstack *obstack;
-
   /* A byte cache where we can stash arbitrary "chunks" of bytes that
      will not change.  */
 
@@ -87,6 +126,17 @@ public:
 
   std::vector<partial_symbol *> global_psymbols;
   std::vector<partial_symbol *> static_psymbols;
+
+private:
+
+  /* List of freed partial symtabs, available for re-use.  */
+
+  struct partial_symtab *free_psymtabs = nullptr;
+
+  /* The obstack where allocations are made.  This is lazily allocated
+     so that we don't waste memory when there are no psymtabs.  */
+
+  gdb::optional<auto_obstack> m_obstack;
 };
 
 
@@ -104,8 +154,7 @@ extern const struct quick_symbol_functions dwarf2_debug_names_functions;
    are loaded.  This function returns a range adapter suitable for
    iterating over the psymtabs of OBJFILE.  */
 
-class objfile_psymtabs;
-extern objfile_psymtabs require_partial_symbols (struct objfile *objfile,
-                                                int verbose);
+extern psymtab_storage::partial_symtab_range require_partial_symbols
+    (struct objfile *objfile, int verbose);
 
 #endif /* PSYMTAB_H */