From ced9779b4c45b9bc9c16dd98fa30d7a620e93a55 Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Wed, 15 Nov 2017 19:02:33 -0500 Subject: (Ada) fix handling of minimal symbols (UNOP_CAST and UNOP_ADDR) Consider a program which provides a symbol without debugging information. For instance, compiling the following code without -g: Some_Minimal_Symbol : Integer := 1234; pragma Export (C, Some_Minimal_Symbol, "some_minsym"); Trying to print this variable with GDB now causes an error, which is now expected: (gdb) p some_minsym 'some_minsym' has unknown type; cast it to its declared type However, trying to cast this symbol, or to take its address does not work: (gdb) p integer(some_minsym) 'some_minsym' has unknown type; cast it to its declared type (gdb) p &some_minsym 'some_minsym' has unknown type; cast it to its declared type Another manisfestation of this issue can be seen when trying to insert an Ada exception catchpoint for a specific standard exception (this only occurs if the Ada runtime is built without debugging information, which is the default). For instance: $ (gdb) catch exception constraint_error warning: failed to reevaluate internal exception condition for catchpoint 0: 'constraint_error' has unknown type; cast it to its declared type This is because, internally, the cachtpoint uses a condition referencing a minimal symbol, more precisely: long_integer (e) = long_integer (&constraint_error) This patch fixes all issues listed above: 1. resolve_subexp: Special-case the handling of OP_VAR_MSYM_VALUE expression elements, where there are no ambiguities to be resolved in that situation; 2. ada_evaluate_subexp: Enhance the handling of the UNOP_CAST handling so as to process the case where the target of the cast is a minimal symbol (as well as a symbol with debugging information). This mimics what's done in C. gdb/ChangeLog: * ada-lang.c (resolve_subexp): Add handling of OP_VAR_MSYM_VALUE. (ada_evaluate_subexp_for_cast): New function. (ada_evaluate_subexp) : Replace code by call to ada_evaluate_subexp_for_cast. (ada_evaluate_subexp) : Replace code by call to eval_skip_value. * eval.c (evaluate_var_value): Make non-static. (evaluate_var_msym_value, eval_skip_value): Likewise. * value.h (evaluate_var_value, evaluate_var_msym_value) (eval_skip_value): Declare. gdb/testsuite/ChangeLog: * gdb.ada/minsyms: New testcase. Tested on x86_64-linux. No regression. Fixes the following failures: catch_ex.exp: continuing to Program_Error exception catch_ex.exp: continuing to failed assertion catch_ex.exp: continuing to unhandled exception catch_ex.exp: continuing to program completion complete.exp: p complete.exp: p Exported_Capitalized complete.exp: p exported_capitalized mi_catch_ex.exp: catch Program_Error (unexpected output) mi_catch_ex.exp: continue to exception catchpoint hit (unknown output after running) mi_catch_ex.exp: continue to assert failure catchpoint hit (unknown output after running) mi_catch_ex.exp: continue to unhandled exception catchpoint hit (unknown output after running) mi_ex_cond.exp: catch C_E if i = 2 (unexpected output) --- gdb/value.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'gdb/value.h') diff --git a/gdb/value.h b/gdb/value.h index b1b8c6ded62..2b6ae35b8a9 100644 --- a/gdb/value.h +++ b/gdb/value.h @@ -875,6 +875,15 @@ extern struct value *evaluate_subexp (struct type *expect_type, extern struct value *evaluate_subexpression_type (struct expression *exp, int subexp); +extern value *evaluate_var_value (enum noside noside, const block *blk, + symbol *var); + +extern value *evaluate_var_msym_value (enum noside noside, + struct objfile *objfile, + minimal_symbol *msymbol); + +extern value *eval_skip_value (expression *exp); + extern void fetch_subexp_value (struct expression *exp, int *pc, struct value **valp, struct value **resultp, struct value **val_chain, -- cgit v1.2.1