From: Joel Brobecker Date: Thu, 16 Nov 2017 00:02:33 +0000 (-0500) Subject: (Ada) fix handling of minimal symbols (UNOP_CAST and UNOP_ADDR) X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ced9779b4c45b9bc9c16dd98fa30d7a620e93a55;p=binutils-gdb.git (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) --- diff --git a/gdb/ChangeLog b/gdb/ChangeLog index aa7c608deaf..1d2c3c5a8d5 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,16 @@ +2017-11-17 Joel Brobecker + + * 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. + 2017-11-16 Joel Brobecker * ada-lang.c (ada_value_cast): Remove parameter "noside". diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c index fe263e6aa49..33c4e8e2fa3 100644 --- a/gdb/ada-lang.c +++ b/gdb/ada-lang.c @@ -3603,7 +3603,12 @@ resolve_subexp (struct expression **expp, int *pos, int deprocedure_p, } *pos = pc; - return evaluate_subexp_type (exp, pos); + if (exp->elts[pc].opcode == OP_VAR_MSYM_VALUE) + return evaluate_var_msym_value (EVAL_AVOID_SIDE_EFFECTS, + exp->elts[pc + 1].objfile, + exp->elts[pc + 2].msymbol); + else + return evaluate_subexp_type (exp, pos); } /* Return non-zero if formal type FTYPE matches actual type ATYPE. If @@ -10313,6 +10318,58 @@ ada_value_cast (struct type *type, struct value *arg2) entity. Results in this case are unpredictable, as we usually read past the buffer containing the data =:-o. */ +/* Evaluate a subexpression of EXP, at index *POS, and return a value + for that subexpression cast to TO_TYPE. Advance *POS over the + subexpression. */ + +static value * +ada_evaluate_subexp_for_cast (expression *exp, int *pos, + enum noside noside, struct type *to_type) +{ + int pc = *pos; + + if (exp->elts[pc].opcode == OP_VAR_MSYM_VALUE + || exp->elts[pc].opcode == OP_VAR_VALUE) + { + (*pos) += 4; + + value *val; + if (exp->elts[pc].opcode == OP_VAR_MSYM_VALUE) + { + if (noside == EVAL_AVOID_SIDE_EFFECTS) + return value_zero (to_type, not_lval); + + val = evaluate_var_msym_value (noside, + exp->elts[pc + 1].objfile, + exp->elts[pc + 2].msymbol); + } + else + val = evaluate_var_value (noside, + exp->elts[pc + 1].block, + exp->elts[pc + 2].symbol); + + if (noside == EVAL_SKIP) + return eval_skip_value (exp); + + val = ada_value_cast (to_type, val); + + /* Follow the Ada language semantics that do not allow taking + an address of the result of a cast (view conversion in Ada). */ + if (VALUE_LVAL (val) == lval_memory) + { + if (value_lazy (val)) + value_fetch_lazy (val); + VALUE_LVAL (val) = not_lval; + } + return val; + } + + value *val = evaluate_subexp (to_type, exp, pos, noside); + if (noside == EVAL_SKIP) + return eval_skip_value (exp); + return ada_value_cast (to_type, val); +} + /* Implement the evaluate_exp routine in the exp_descriptor structure for the Ada language. */ @@ -10371,11 +10428,7 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp, case UNOP_CAST: (*pos) += 2; type = exp->elts[pc + 1].type; - arg1 = evaluate_subexp (type, exp, pos, noside); - if (noside == EVAL_SKIP) - goto nosideret; - arg1 = ada_value_cast (type, arg1); - return arg1; + return ada_evaluate_subexp_for_cast (exp, pos, noside, type); case UNOP_QUAL: (*pos) += 2; @@ -11347,7 +11400,7 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp, } nosideret: - return value_from_longest (builtin_type (exp->gdbarch)->builtin_int, 1); + return eval_skip_value (exp); } diff --git a/gdb/eval.c b/gdb/eval.c index 94ddfdb6ae4..14a3e05ade2 100644 --- a/gdb/eval.c +++ b/gdb/eval.c @@ -705,7 +705,7 @@ fake_method::~fake_method () /* Helper for evaluating an OP_VAR_VALUE. */ -static value * +value * evaluate_var_value (enum noside noside, const block *blk, symbol *var) { /* JYG: We used to just return value_zero of the symbol type if @@ -738,7 +738,7 @@ evaluate_var_value (enum noside noside, const block *blk, symbol *var) /* Helper for evaluating an OP_VAR_MSYM_VALUE. */ -static value * +value * evaluate_var_msym_value (enum noside noside, struct objfile *objfile, minimal_symbol *msymbol) { @@ -757,7 +757,7 @@ evaluate_var_msym_value (enum noside noside, /* Helper for returning a value when handling EVAL_SKIP. */ -static value * +value * eval_skip_value (expression *exp) { return value_from_longest (builtin_type (exp->gdbarch)->builtin_int, 1); diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index c70c65083c5..7334fd73733 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2017-11-17 Joel Brobecker + + * gdb.ada/minsyms: New testcase. + 2017-11-16 Pedro Alves * gdb.base/bp-cmds-continue-ctrl-c.c: New file. diff --git a/gdb/testsuite/gdb.ada/minsyms.exp b/gdb/testsuite/gdb.ada/minsyms.exp new file mode 100644 index 00000000000..2c91125899a --- /dev/null +++ b/gdb/testsuite/gdb.ada/minsyms.exp @@ -0,0 +1,41 @@ +# Copyright 2017 Free Software Foundation, Inc. +# +# 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 . + +load_lib "ada.exp" + +standard_ada_testfile foo_qb07_057 + +if {[gdb_compile_ada "${srcfile}" "${binfile}" executable ""] != "" } { + return -1 +} + +clean_restart ${testfile} + +if ![runto "_ada_foo_qb07_057" ] then { + perror "Couldn't run ${testfile}" + return +} + +gdb_test "print some_minsym" \ + "'some_minsym' has unknown type; cast it to its declared type" + +gdb_test "print integer(some_minsym)" \ + " = 1234" + +gdb_test "print &some_minsym" \ + " = \\(access \\) 0x62c2f8 " + +gdb_test "print /x integer(&some_minsym)" \ + " = $hex" diff --git a/gdb/testsuite/gdb.ada/minsyms/foo_qb07_057.adb b/gdb/testsuite/gdb.ada/minsyms/foo_qb07_057.adb new file mode 100644 index 00000000000..5a081dc18a1 --- /dev/null +++ b/gdb/testsuite/gdb.ada/minsyms/foo_qb07_057.adb @@ -0,0 +1,20 @@ +-- Copyright 2017 Free Software Foundation, Inc. +-- +-- 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 . + +with Pck; use Pck; +procedure Foo_QB07_057 is +begin + Increment (Some_Minimal_Symbol); +end Foo_QB07_057; diff --git a/gdb/testsuite/gdb.ada/minsyms/pck.adb b/gdb/testsuite/gdb.ada/minsyms/pck.adb new file mode 100644 index 00000000000..10e8c9bd31e --- /dev/null +++ b/gdb/testsuite/gdb.ada/minsyms/pck.adb @@ -0,0 +1,21 @@ +-- Copyright 2017 Free Software Foundation, Inc. +-- +-- 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 . + +package body Pck is + procedure Increment (I: in out Integer) is + begin + I := I + 1; + end Increment; +end Pck; diff --git a/gdb/testsuite/gdb.ada/minsyms/pck.ads b/gdb/testsuite/gdb.ada/minsyms/pck.ads new file mode 100644 index 00000000000..4ad4c07837e --- /dev/null +++ b/gdb/testsuite/gdb.ada/minsyms/pck.ads @@ -0,0 +1,21 @@ +-- Copyright 2017 Free Software Foundation, Inc. +-- +-- 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 . + +package Pck is + Some_Minimal_Symbol : Integer := 1234; + pragma Export (C, Some_Minimal_Symbol, "some_minsym"); + + procedure Increment (I: in out Integer); +end Pck; 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,