Set language for Ada minimal symbols.

This helps with the following issue: Given an Ada program defining
a global variable:

    package Pck is
       Watch : Integer := 1974;
    end Pck;

When printing the address of this variable, GDB also tries to print
the associated symbol name:

    (gdb) p watch'address
    $1 = (access integer) 0x6139d8 <pck__watch>
                                       ^^
                                       ||

The problem is that GDB prints the variable's linkage name, instead
of its natural name. This is because the language of the associated
minimal symbol never really gets set.

This patch adds handling for Ada symbols in symbol_find_demangled_name.
After this patch, we now get:

    (gdb) p watch'address
    $1 = (access integer) 0x6139d8 <pck.watch>
                                       ^
                                       |

gdb/ChangeLog:

        * symtab.c (symbol_find_demangled_name): Add handling of
        Ada symbols.

gdb/testsuite/ChangeLog:

        * gdb.ada/int_deref.exp: Add test verifying that we print
        the decoded symbol name when printing the address of Ada
        symbols.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f8790e75940f29267efb4e61ff2d994cd4608a24..d9e492f00b341240206fe134db982aa578ad6303 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2013-12-10  Joel Brobecker  <brobecker@adacore.com>
+
+       * symtab.c (symbol_find_demangled_name): Add handling of
+       Ada symbols.
+
 2013-12-10  Joel Brobecker  <brobecker@adacore.com>
 
        * mi/mi-main.c (mi_cmd_list_features): add "exec-run-start-option".

diff --git a/gdb/symtab.c b/gdb/symtab.c
index 8fac0be9ef0f02a76d81dfba304774674e725c28..aa1e14b09240dd7defe4a09e1c5a1fc79c1afac4 100644 (file)
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -60,6 +60,7 @@
 #include "solist.h"
 #include "macrotab.h"
 #include "macroscope.h"
+#include "ada-lang.h"
 
 #include "psymtab.h"
 #include "parser-defs.h"
@@ -692,6 +693,42 @@ symbol_find_demangled_name (struct general_symbol_info *gsymbol,
      symbols).  Just the mangling standard is not standardized across compilers
      and there is no DW_AT_producer available for inferiors with only the ELF
      symbols to check the mangling kind.  */
+
+  /* Check for Ada symbols last.  See comment below explaining why.  */
+
+  if (gsymbol->language == language_auto)
+   {
+     const char *demangled = ada_decode (mangled);
+
+     if (demangled != mangled && demangled != NULL && demangled[0] != '<')
+       {
+        /* Set the gsymbol language to Ada, but still return NULL.
+           Two reasons for that:
+
+             1. For Ada, we prefer computing the symbol's decoded name
+                on the fly rather than pre-compute it, in order to save
+                memory (Ada projects are typically very large).
+
+             2. There are some areas in the definition of the GNAT
+                encoding where, with a bit of bad luck, we might be able
+                to decode a non-Ada symbol, generating an incorrect
+                demangled name (Eg: names ending with "TB" for instance
+                are identified as task bodies and so stripped from
+                the decoded name returned).
+
+                Returning NULL, here, helps us get a little bit of
+                the best of both worlds.  Because we're last, we should
+                not affect any of the other languages that were able to
+                demangle the symbol before us; we get to correctly tag
+                Ada symbols as such; and even if we incorrectly tagged
+                a non-Ada symbol, which should be rare, any routing
+                through the Ada language should be transparent (Ada
+                tries to behave much like C/C++ with non-Ada symbols).  */
+        gsymbol->language = language_ada;
+        return NULL;
+       }
+   }
+
   return NULL;
 }
 

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 08f6b27dd3aa85e6f86e498682c1cc1fc9bea8bf..0e1e78501f10e5e6f6115ad84fda39842f237c30 100644 (file)
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2013-12-10  Joel Brobecker  <brobecker@adacore.com>
+
+       * gdb.ada/int_deref.exp: Add test verifying that we print
+       the decoded symbol name when printing the address of Ada
+       symbols.
+
 2013-12-10  Joel Brobecker  <brobecker@adacore.com>
 
        * gdb.mi/mi-start.exp: Add test verifying that -list-features

diff --git a/gdb/testsuite/gdb.ada/int_deref.exp b/gdb/testsuite/gdb.ada/int_deref.exp
index 7b8f426750363f107224beea3b4be689c84a611d..ea61d4a0f7b33186d890b516747a7381e9452e64 100644 (file)
--- a/gdb/testsuite/gdb.ada/int_deref.exp
+++ b/gdb/testsuite/gdb.ada/int_deref.exp
@@ -26,6 +26,11 @@ clean_restart ${testfile}
 set bp_location [gdb_get_line_number "Pck.Watch" ${testdir}/foo.adb]
 runto "foo.adb:$bp_location"
 
+# Hijack a bit this testcase, to verify that name decoding works
+# when doing symbolic address printing.
+gdb_test "print watch'address" \
+         " = \\(system\\.address\\) $hex <pck\\.watch>"
+
 gdb_test "print *long_integer(watch'address)" \
          " = 4874"