From 3bce82377f683870cc89925ff43aefb7dcce4a77 Mon Sep 17 00:00:00 2001 From: Sanimir Agovic Date: Wed, 5 Feb 2014 16:22:08 +0000 Subject: [PATCH] vla: evaluate operand of sizeof if its type is a vla The c99 standard in "6.5.3.4 The sizeof operator" states: If the type of the operand is a variable length array type, the operand is evaluated;[...] This patch mirrors the following c99 semantic in gdb: 1| int vla[n][m]; 2| int i = 1; 3| sizeof(vla[i++][0]); // No sideffect 4| assert (i == 1); 5| sizeof(vla[i++]); // With sideffect 6| assert (i == 2); Note: ptype/whatsis still do not allow any sideeffects. This patch was motivated by: https://sourceware.org/ml/gdb-patches/2014-01/msg00732.html * eval.c (evaluate_subexp_for_sizeof): Add enum noside argument. (evaluate_subexp_standard): Pass noside argument. (evaluate_subexp_for_sizeof) : Handle subscript case if noside equals EVAL_NORMAL. If the subscript yields a vla type re-evaluate subscript operation with EVAL_NORMAL to enable sideffects. * gdbtypes.c (resolve_dynamic_bounds): Mark bound as evaluated. * gdbtypes.h (enum range_flags): Add RANGE_EVALUATED case. testsuite/gdb.base/ * vla-sideeffect.c: New file. * vla-sideeffect.exp: New file. --- gdb/ChangeLog | 10 ++++ gdb/eval.c | 43 +++++++++++++-- gdb/gdbtypes.c | 1 + gdb/gdbtypes.h | 5 ++ gdb/testsuite/ChangeLog | 5 ++ gdb/testsuite/gdb.base/vla-sideeffect.c | 42 +++++++++++++++ gdb/testsuite/gdb.base/vla-sideeffect.exp | 89 +++++++++++++++++++++++++++++++ 7 files changed, 191 insertions(+), 4 deletions(-) create mode 100644 gdb/testsuite/gdb.base/vla-sideeffect.c create mode 100644 gdb/testsuite/gdb.base/vla-sideeffect.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 137dba4..48fb279 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,15 @@ 2014-04-11 Sanimir Agovic + * eval.c (evaluate_subexp_for_sizeof): Add enum noside argument. + (evaluate_subexp_standard): Pass noside argument. + (evaluate_subexp_for_sizeof) : Handle subscript case + if noside equals EVAL_NORMAL. If the subscript yields a vla type + re-evaluate subscript operation with EVAL_NORMAL to enable sideffects. + * gdbtypes.c (resolve_dynamic_bounds): Mark bound as evaluated. + * gdbtypes.h (enum range_flags): Add RANGE_EVALUATED case. + +2014-04-11 Sanimir Agovic + * findvar.c (default_read_var_value): Resolve dynamic bounds if location points to a constant blob. diff --git a/gdb/eval.c b/gdb/eval.c index 1074e1d..d29960a 100644 --- a/gdb/eval.c +++ b/gdb/eval.c @@ -50,7 +50,8 @@ extern int overload_resolution; /* Prototypes for local functions. */ -static struct value *evaluate_subexp_for_sizeof (struct expression *, int *); +static struct value *evaluate_subexp_for_sizeof (struct expression *, int *, + enum noside); static struct value *evaluate_subexp_for_address (struct expression *, int *, enum noside); @@ -2562,7 +2563,7 @@ evaluate_subexp_standard (struct type *expect_type, evaluate_subexp (NULL_TYPE, exp, pos, EVAL_SKIP); goto nosideret; } - return evaluate_subexp_for_sizeof (exp, pos); + return evaluate_subexp_for_sizeof (exp, pos, noside); case UNOP_CAST: (*pos) += 2; @@ -2997,10 +2998,13 @@ evaluate_subexp_with_coercion (struct expression *exp, /* Evaluate a subexpression of EXP, at index *POS, and return a value for the size of that subexpression. - Advance *POS over the subexpression. */ + Advance *POS over the subexpression. If NOSIDE is EVAL_NORMAL + we allow side-effects on the operand if its type is a variable + length array. */ static struct value * -evaluate_subexp_for_sizeof (struct expression *exp, int *pos) +evaluate_subexp_for_sizeof (struct expression *exp, int *pos, + enum noside noside) { /* FIXME: This should be size_t. */ struct type *size_type = builtin_type (exp->gdbarch)->builtin_int; @@ -3054,6 +3058,37 @@ evaluate_subexp_for_sizeof (struct expression *exp, int *pos) return value_from_longest (size_type, (LONGEST) TYPE_LENGTH (type)); + /* Deal with the special case if NOSIDE is EVAL_NORMAL and the resulting + type of the subscript is a variable length array type. In this case we + must re-evaluate the right hand side of the subcription to allow + side-effects. */ + case BINOP_SUBSCRIPT: + if (noside == EVAL_NORMAL) + { + int pc = (*pos) + 1; + + val = evaluate_subexp (NULL_TYPE, exp, &pc, EVAL_AVOID_SIDE_EFFECTS); + type = check_typedef (value_type (val)); + if (TYPE_CODE (type) == TYPE_CODE_ARRAY) + { + type = check_typedef (TYPE_TARGET_TYPE (type)); + if (TYPE_CODE (type) == TYPE_CODE_ARRAY) + { + type = TYPE_INDEX_TYPE (type); + /* Only re-evaluate the right hand side if the resulting type + is a variable length type. */ + if (TYPE_RANGE_DATA (type)->flag_bound_evaluated) + { + val = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_NORMAL); + return value_from_longest + (size_type, (LONGEST) TYPE_LENGTH (value_type (val))); + } + } + } + } + + /* Fall through. */ + default: val = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_AVOID_SIDE_EFFECTS); return value_from_longest (size_type, diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c index b7b4210..47b2120 100644 --- a/gdb/gdbtypes.c +++ b/gdb/gdbtypes.c @@ -1708,6 +1708,7 @@ resolve_dynamic_bounds (struct type *type, CORE_ADDR addr) range_type = create_range_type (NULL, TYPE_TARGET_TYPE (range_type), &low_bound, &high_bound); + TYPE_RANGE_DATA (range_type)->flag_bound_evaluated = 1; return create_array_type (copy_type (type), elt_type, range_type); diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h index 6c3bb33..4c9d7c2 100644 --- a/gdb/gdbtypes.h +++ b/gdb/gdbtypes.h @@ -668,6 +668,11 @@ struct main_type subrange. This affects how the final hight bound is computed. */ int flag_upper_bound_is_count : 1; + + /* True if LOW or/and HIGH are resolved into a static bound from + a dynamic one. */ + + int flag_bound_evaluated : 1; } *bounds; } flds_bnds; diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index d1926dd..f598e56 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2014-04-11 Sanimir Agovic + + * vla-sideeffect.c: New file. + * vla-sideeffect.exp: New file. + 2014-04-11 Yao Qi * gdb.base/completion.exp: Check file exists before running tests diff --git a/gdb/testsuite/gdb.base/vla-sideeffect.c b/gdb/testsuite/gdb.base/vla-sideeffect.c new file mode 100644 index 0000000..6e42a64 --- /dev/null +++ b/gdb/testsuite/gdb.base/vla-sideeffect.c @@ -0,0 +1,42 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2014 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 . */ + +#include +#define SIZE 10 + +int +main (void) +{ + int n = SIZE; + int i = 0; + int j = 0; + int vla2[SIZE][n]; + int vla1[n]; + + for (i = 0; i < n; i++) + vla1[i] = (i * 2) + n; + + for (i = 0; i < SIZE; i++) + for (j = 0; j < n; j++) + vla2[i][j] = (i + j) + n; + + + i = 0; + j = 0; + + return 0; /* vla-filled */ +} diff --git a/gdb/testsuite/gdb.base/vla-sideeffect.exp b/gdb/testsuite/gdb.base/vla-sideeffect.exp new file mode 100644 index 0000000..517d78b --- /dev/null +++ b/gdb/testsuite/gdb.base/vla-sideeffect.exp @@ -0,0 +1,89 @@ +# Copyright 2014 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 . + +# Tests side-effects of sizeof evaluation. +# Based on gcc/testsuite/gcc.dg/vla-4.c; vla-15.c + +standard_testfile + +if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } { + return -1 +} + +if ![runto_main] { + return -1 +} + +gdb_breakpoint [gdb_get_line_number "vla-filled"] +gdb_continue_to_breakpoint "vla-filled" + +# Check side effects for sizeof argument. +set sizeof_int [get_sizeof "int" 4] +set sizeof_vla [ expr "10" * "$sizeof_int" ] + +gdb_test "print sizeof (vla1\[i++\])" " = ${sizeof_int}" \ + "print sizeof (vla1\[i++\])" +gdb_test "print i" " = 0" \ + "print i - sizeof no side effects" + +gdb_test "print sizeof (++vla1\[0\])" " = ${sizeof_int}" \ + "print sizeof (++vla1\[0\])" +gdb_test "print vla1\[0\]" " = 10" \ + "print vla1\[0\] - sizeof no side effects" + +gdb_test "ptype ++vla1\[0\]" "type = int" "ptype ++vla1\[0\]" +gdb_test "print vla1\[0\]" " = 10" \ + "print vla1\[0\] - ptype no side effects" + +gdb_test "whatis ++vla1\[0\]" "type = int" "whatis ++vla1\[0\]" +gdb_test "print vla1\[0\]" " = 10" \ + "print vla1\[0\] - whatis no side effects" + + +gdb_test "print sizeof (vla2\[i++\])" " = ${sizeof_vla}" \ + "print sizeof (vla2\[i++\])" +gdb_test "print i" " = 1" \ + "print i - sizeof with side effects (1)" + +gdb_test "print sizeof (vla2\[i++ + sizeof(j++)\])" " = ${sizeof_vla}" \ + "print sizeof (vla2\[i++ + sizeof(j++)\])" +gdb_test "print i" " = 2" \ + "print i - sizeof with side effects (2)" +gdb_test "print j" " = 0" \ + "print j - sizeof with no side effects" + +gdb_test "ptype vla2\[i++\]" "type = int \\\[10\\\]" \ + "ptype vla2\[i++\]" +gdb_test "print i" " = 2" \ + "print i - ptype with side effects (1)" + +gdb_test "ptype vla2\[i++ + sizeof(j++)\]" "type = int \\\[10\\\]" \ + "ptype vla2\[i++ + sizeof(j++)\]" +gdb_test "print i" " = 2" \ + "print i - ptype with side effects (2)" +gdb_test "print j" " = 0" \ + "print j - ptype with no side effects" + +gdb_test "whatis vla2\[i++\]" "type = int \\\[10\\\]" \ + "whatis vla2\[i++\]" +gdb_test "print i" " = 2" \ + "print i - whatis with side effects (1)" + +gdb_test "whatis vla2\[i++ + sizeof(j++)\]" "type = int \\\[10\\\]" \ + "whatis vla2\[i++ + sizeof(j++)\]" +gdb_test "print i" " = 2" \ + "print i - whatis with side effects (2)" +gdb_test "print j" " = 0" \ + "print j - whatis with no side effects" -- 2.7.4