1 files changed, 67 insertions, 6 deletions

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index eb5d924..81b20c7 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -404,6 +404,13 @@ struct dwarf2_cu
      DIEs for namespaces, we don't need to try to infer them
      from mangled names.  */
   unsigned int has_namespace_info : 1;
+
+  /* This CU references .debug_loc.  See the symtab->locations_valid field.
+     This test is imperfect as there may exist optimized debug code not using
+     any location list and still facing inlining issues if handled as
+     unoptimized code.  For a future better test see GCC PR other/32998.  */
+
+  unsigned int has_loclist : 1;
 };
 
 /* Persistent data held for a compilation unit, even when not
@@ -4610,6 +4617,44 @@ compute_delayed_physnames (struct dwarf2_cu *cu)
     }
 }
 
+/* Check for GCC >= 4.0.  */
+
+static int
+producer_is_gcc_ge_4_0 (struct dwarf2_cu *cu)
+{
+  const char *cs;
+  int major, minor;
+
+  if (cu->producer == NULL)
+    {
+      /* For unknown compilers expect their behavior is not compliant.  For GCC
+	 this case can also happen for -gdwarf-4 type units supported since
+	 gcc-4.5.  */
+
+      return 0;
+    }
+
+  /* Skip any identifier after "GNU " - such as "C++" or "Java".  */
+
+  if (strncmp (cu->producer, "GNU ", strlen ("GNU ")) != 0)
+    {
+      /* For non-GCC compilers expect their behavior is not compliant.  */
+
+      return 0;
+    }
+  cs = &cu->producer[strlen ("GNU ")];
+  while (*cs && !isdigit (*cs))
+    cs++;
+  if (sscanf (cs, "%d.%d", &major, &minor) != 2)
+    {
+      /* Not recognized as GCC.  */
+
+      return 0;
+    }
+
+  return major >= 4;
+}
+
 /* Generate full symbol information for PST and CU, whose DIEs have
    already been loaded into memory.  */
 
@@ -4649,13 +4694,26 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu)
 
   symtab = end_symtab (highpc + baseaddr, objfile, SECT_OFF_TEXT (objfile));
 
-  /* Set symtab language to language from DW_AT_language.
-     If the compilation is from a C file generated by language preprocessors,
-     do not set the language if it was already deduced by start_subfile.  */
-  if (symtab != NULL
-      && !(cu->language == language_c && symtab->language != language_c))
+  if (symtab != NULL)
     {
-      symtab->language = cu->language;
+      /* Set symtab language to language from DW_AT_language.  If the
+	 compilation is from a C file generated by language preprocessors, do
+	 not set the language if it was already deduced by start_subfile.  */
+      if (!(cu->language == language_c && symtab->language != language_c))
+	symtab->language = cu->language;
+
+      /* GCC-4.0 has started to support -fvar-tracking.  GCC-3.x still can
+	 produce DW_AT_location with location lists but it can be possibly
+	 invalid without -fvar-tracking.
+
+	 For -gdwarf-4 type units LOCATIONS_VALID indication is fortunately not
+	 needed, it would be wrong due to missing DW_AT_producer there.
+
+	 Still one can confuse GDB by using non-standard GCC compilation
+	 options - this waits on GCC PR other/32998 (-frecord-gcc-switches).
+	 */ 
+      if (cu->has_loclist && producer_is_gcc_ge_4_0 (cu))
+	symtab->locations_valid = 1;
     }
 
   if (dwarf2_per_objfile->using_index)
@@ -10968,6 +11026,9 @@ var_decode_location (struct attribute *attr, struct symbol *sym,
 
   dwarf2_symbol_mark_computed (attr, sym, cu);
   SYMBOL_CLASS (sym) = LOC_COMPUTED;
+
+  if (SYMBOL_COMPUTED_OPS (sym) == &dwarf2_loclist_funcs)
+    cu->has_loclist = 1;
 }
 
 /* Given a pointer to a DWARF information entry, figure out if we need