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Re: [PATCH] Forbid watchpoint on a constant value
- From: Sergio Durigan Junior <sergiodj at redhat dot com>
- To: Joel Brobecker <brobecker at adacore dot com>
- Cc: gdb-patches at sourceware dot org, tromey at redhat dot com, Jan Kratochvil <jan dot kratochvil at redhat dot com>
- Date: Sat, 5 Jun 2010 01:50:08 -0300
- Subject: Re: [PATCH] Forbid watchpoint on a constant value
- References: <20100521070500.GA30452@host0.dyn.jankratochvil.net> <201005211912.39680.sergiodj@redhat.com> <20100528231122.GO3019@adacore.com>
Hi Joel, Tom, Jan
On Friday 28 May 2010 20:11:22, Joel Brobecker wrote:
> > +/* This checks if each element of EXP is not a
> > + constant expression for a watchpoint.
> > +
> > + Returns 1 if EXP is constant, 0 otherwise. */
>
> We usually use a more imperative style: "do this, do that", as opposed
> to "this does this, this does that". The negation seems a little weird
> too. It's no biggie, but I think that your line length is quite shorter
> than usual, making the comment a little odd... Here's a suggestion as
> a starting point:
>
> /* Return non-zero iff EXP is an expression whose value can never change. */
Replaced by Jan's version of it.
> > +static int
> > +watchpoint_exp_is_const (struct expression *exp)
>
> Just a thought that crossed my mind: Can this parameter be declared as
> a const?
Fixed, and also constified the parameters from the operator_length class
of functions.
> > + /* If it's an OP_VAR_VALUE, then we must check if the `symbol'
> > + element does not correspond to a function or to a constant
> > + value. If it does, then it is a constant address. */
>
> Same stylistic remark as at the beginning: The use of the negation here
> makes things a little confusing. How about:
>
> - Write something like that:
>
> /* Check whether the associated symbol is a constant.
> We use the symbol class rather than the type because [...].
> We also have to be careful that function symbols are not
> always indicative of a constant, due to the fact that this
> expression might be calling that function. */
I rewrote the comment based on a new version of the patch (details below),
but thanks for the suggestion.
> > + /* The default action is to return 0 because we are using
> > + the optimistic approach here: if we don't know something,
> > + then it is not a constant. */
> > + default:
>
> Capital 'I' after the colon...
That one I didn't know :-). One more to the list of grammar rules.
> > + gdb_test_multiple "next" "next over global_ptr_ptr init" {
> > + -re ".*atchpoint \[0-9\]+: \\*\\*global_ptr_ptr\r\n\r\nOld value = .*\r\nNew value = 7 .*\r\n.*$gdb_prompt $" {
> > + # We can not test for <unknown> here because NULL may be readable.
> > + # This test does rely on *NULL != 7.
> > + pass "next over global_ptr_ptr init"
> > + }
> > + }
> > + gdb_test_multiple "next" "next over global_ptr_ptr buffer set" {
> > + -re ".*atchpoint \[0-9\]+: \\*\\*global_ptr_ptr\r\n\r\nOld value = 7 .*\r\nNew value = 9 .*\r\n.*$gdb_prompt $" {
> > + pass "next over global_ptr_ptr buffer set"
> > + }
> > + }
> > + gdb_test_multiple "next" "next over global_ptr_ptr pointer advance" {
> > + -re ".*atchpoint \[0-9\]+: \\*\\*global_ptr_ptr\r\n\r\nOld value = 9 .*\r\nNew value = 5 .*\r\n.*$gdb_prompt $" {
> > + pass "next over global_ptr_ptr pointer advance"
> > + }
> > + }
>
> I'm wondering why you are using gdb_test_multiple in these cases, rather
> than just gdb_test?
Sorry about that. Fixed.
> > + # See above.
> > + if [istarget "mips-idt-*"] then {
> > + gdb_exit
> > + gdb_start
> > + gdb_reinitialize_dir $srcdir/$subdir
> > + gdb_load $binfile
> > + initialize
>
> The "gdb_exit ... gdb_load" part of the above can be simplified by
> using: clean_restart. I should probably add that to the wiki (we have
> a cookbook on how to write testcases).
Thanks for the tip! Fixed.
> > +if {![istarget *-*-linux*]
> > + && ![istarget *-*-gnu*]
> > + && ![istarget *-*-elf*]
> > + && ![istarget *-*-openbsd*]
> > + && ![istarget arm-*-eabi*]
> > + && ![istarget powerpc-*-eabi*]} {
> > + return 0
> > +}
>
> We need to add a comment explaining why... Is it because we need
> a specific assembler/linker?
I strongly based this testcase on gdb.dwarf2/pieces.exp, so I added the
same comment I found there:
# This test can only be run on targets which support DWARF-2 and use gas.
# For now pick a sampling of likely targets.
I hope that's enough :-).
Well, here's the refreshed-and-corrected version of the patch. One thing to
notice is that instead of doing:
if (!TYPE_CONST (SYMBOL_TYPE (s)) != TYPE_CODE_FUNC
...
I am now doing:
if (!SYMBOL_CLASS (s) != LOC_BLOCK
...
Jan kindly suggested me to do this change, and I checked the DWARF spec in
order to see if LOC_BLOCK is equivalent to TYPE_CODE_FUNC. As it is, I
decided to replace.
Thanks.
--
Sergio Durigan Junior
Red Hat
gdb/ChangeLog:
2010-06-05 Jan Kratochvil <jan.kratochvil@redhat.com>
Sergio Durigan Junior <sergiodj@redhat.com>
* breakpoint.c: Include parser-defs.h.
(watchpoint_exp_is_const): New function.
(watch_command_1): Call watchpoint_exp_is_const to check
if the expression is constant.
gdb/doc/ChangeLog:
2010-06-05 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.texinfo: Include information about the correct use
of addresses in the `watch' command.
gdb/testsuite/ChangeLog:
2010-06-05 Jan Kratochvil <jan.kratochvil@redhat.com>
Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.base/watch-notconst.c: New file.
* gdb.base/watch-notconst.S: New file.
* gdb.base/watch-notconst2.c: New file.
* gdb.base/watch-notconst2.S: New file.
* gdb.base/watch-notconst.exp: New file.
* gdb.base/watchpoint.c (global_ptr_ptr): New variable.
(func4): Add operations on `global_ptr_ptr'.
* gdb.base/watchpoint.exp (test_constant_watchpoint): New
routine to test watchpoints created with a constant expression.
(test_inaccessible_watchpoint): Include tests for watchpoints
created with a constant expression.
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 1fc155a..a1b335d 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -61,6 +61,7 @@
#include "valprint.h"
#include "jit.h"
#include "xml-syscall.h"
+#include "parser-defs.h"
/* readline include files */
#include "readline/readline.h"
@@ -186,6 +187,8 @@ static void stopin_command (char *arg, int from_tty);
static void stopat_command (char *arg, int from_tty);
+static int watchpoint_exp_is_const (const struct expression *exp);
+
static char *ep_parse_optional_if_clause (char **arg);
static void catch_exception_command_1 (enum exception_event_kind ex_event,
@@ -7700,6 +7703,111 @@ stopat_command (char *arg, int from_tty)
break_command_1 (arg, 0, from_tty);
}
+/* Return non-zero if EXP is verified as constant. Returned zero means EXP is
+ variable. Also the constant detection may fail for some constant
+ expressions and in such case still falsely return zero. */
+static int
+watchpoint_exp_is_const (const struct expression *exp)
+{
+ int i = exp->nelts;
+
+ while (i > 0)
+ {
+ int oplenp, argsp;
+
+ /* We are only interested in the descriptor of each element. */
+ operator_length (exp, i, &oplenp, &argsp);
+ i -= oplenp;
+
+ switch (exp->elts[i].opcode)
+ {
+ case BINOP_ADD:
+ case BINOP_SUB:
+ case BINOP_MUL:
+ case BINOP_DIV:
+ case BINOP_REM:
+ case BINOP_MOD:
+ case BINOP_LSH:
+ case BINOP_RSH:
+ case BINOP_LOGICAL_AND:
+ case BINOP_LOGICAL_OR:
+ case BINOP_BITWISE_AND:
+ case BINOP_BITWISE_IOR:
+ case BINOP_BITWISE_XOR:
+ case BINOP_EQUAL:
+ case BINOP_NOTEQUAL:
+ case BINOP_LESS:
+ case BINOP_GTR:
+ case BINOP_LEQ:
+ case BINOP_GEQ:
+ case BINOP_REPEAT:
+ case BINOP_COMMA:
+ case BINOP_EXP:
+ case BINOP_MIN:
+ case BINOP_MAX:
+ case BINOP_INTDIV:
+ case BINOP_CONCAT:
+ case BINOP_IN:
+ case BINOP_RANGE:
+ case TERNOP_COND:
+ case TERNOP_SLICE:
+ case TERNOP_SLICE_COUNT:
+
+ case OP_LONG:
+ case OP_DOUBLE:
+ case OP_DECFLOAT:
+ case OP_LAST:
+ case OP_COMPLEX:
+ case OP_STRING:
+ case OP_BITSTRING:
+ case OP_ARRAY:
+ case OP_TYPE:
+ case OP_NAME:
+ case OP_OBJC_NSSTRING:
+
+ case UNOP_NEG:
+ case UNOP_LOGICAL_NOT:
+ case UNOP_COMPLEMENT:
+ case UNOP_ADDR:
+ case UNOP_HIGH:
+ /* Unary, binary and ternary operators: We have to check their
+ operands. If they are constant, then so is the result of
+ that operation. For instance, if A and B are determined to be
+ constants, then so is "A + B".
+
+ UNOP_IND is one exception to the rule above, because the value
+ of *ADDR is not necessarily a constant, even when ADDR is. */
+ break;
+
+ case OP_VAR_VALUE:
+ /* Check whether the associated symbol is a constant.
+ We use SYMBOL_CLASS rather than TYPE_CONST because it's
+ possible that a buggy compiler could mark a variable as constant
+ even when it is not, and TYPE_CONST would return true in this
+ case, while SYMBOL_CLASS wouldn't.
+ We also have to check for function symbols because they are
+ always constant. */
+ {
+ struct symbol *s = exp->elts[i + 2].symbol;
+
+ if (SYMBOL_CLASS (s) != LOC_BLOCK
+ && SYMBOL_CLASS (s) != LOC_CONST
+ && SYMBOL_CLASS (s) != LOC_CONST_BYTES)
+ return 0;
+ break;
+ }
+
+ /* The default action is to return 0 because we are using
+ the optimistic approach here: If we don't know something,
+ then it is not a constant. */
+ default:
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
/* accessflag: hw_write: watch write,
hw_read: watch read,
hw_access: watch access (read or write) */
@@ -7794,6 +7902,17 @@ watch_command_1 (char *arg, int accessflag, int from_tty)
while (exp_end > exp_start && (exp_end[-1] == ' ' || exp_end[-1] == '\t'))
--exp_end;
+ /* Checking if the expression is not constant. */
+ if (watchpoint_exp_is_const (exp))
+ {
+ int len;
+
+ len = exp_end - exp_start;
+ while (len > 0 && isspace (exp_start[len - 1]))
+ len--;
+ error (_("Cannot watch constant value `%.*s'."), len, exp_start);
+ }
+
exp_valid_block = innermost_block;
mark = value_mark ();
fetch_watchpoint_value (exp, &val, NULL, NULL);
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index fa7a0ec..98d4565 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -3725,6 +3725,18 @@ This command prints a list of watchpoints, using the same format as
@code{info break} (@pxref{Set Breaks}).
@end table
+If you watch for a change in a numerically entered address you need to
+dereference it, as the address itself is just a constant number which will
+never change. @value{GDBN} refuses to create a watchpoint that watches
+a never-changing value:
+
+@smallexample
+(@value{GDBP}) watch 0x600850
+Cannot watch constant value 0x600850.
+(@value{GDBP}) watch *(int *) 0x600850
+Watchpoint 1: *(int *) 6293584
+@end smallexample
+
@value{GDBN} sets a @dfn{hardware watchpoint} if possible. Hardware
watchpoints execute very quickly, and the debugger reports a change in
value at the exact instruction where the change occurs. If @value{GDBN}
diff --git a/gdb/testsuite/gdb.base/watchpoint.c b/gdb/testsuite/gdb.base/watchpoint.c
index 9275d88..8c212c1 100644
--- a/gdb/testsuite/gdb.base/watchpoint.c
+++ b/gdb/testsuite/gdb.base/watchpoint.c
@@ -40,6 +40,7 @@ struct foo struct1, struct2, *ptr1, *ptr2;
int doread = 0;
char *global_ptr;
+char **global_ptr_ptr;
void marker1 ()
{
@@ -119,6 +120,10 @@ func4 ()
buf[0] = 3;
global_ptr = buf;
buf[0] = 7;
+ buf[1] = 5;
+ global_ptr_ptr = &global_ptr;
+ buf[0] = 9;
+ global_ptr++;
}
int main ()
diff --git a/gdb/testsuite/gdb.base/watchpoint.exp b/gdb/testsuite/gdb.base/watchpoint.exp
index 56d82e4..e2eea71 100644
--- a/gdb/testsuite/gdb.base/watchpoint.exp
+++ b/gdb/testsuite/gdb.base/watchpoint.exp
@@ -617,7 +617,19 @@ proc test_watchpoint_and_breakpoint {} {
}
}
}
-
+
+proc test_constant_watchpoint {} {
+ gdb_test "watch 5" "Cannot watch constant value `5'." "number is constant"
+ gdb_test "watch marker1" "Cannot watch constant value `marker1'." \
+ "marker1 is constant"
+ gdb_test "watch count + 6" ".*atchpoint \[0-9\]+: count \\+ 6"
+ gdb_test_no_output "set \$expr_breakpoint_number = \$bpnum"
+ gdb_test_no_output "delete \$expr_breakpoint_number"
+ gdb_test "watch 7 + count" ".*atchpoint \[0-9\]+: 7 \\+ count"
+ gdb_test_no_output "set \$expr_breakpoint_number = \$bpnum"
+ gdb_test_no_output "delete \$expr_breakpoint_number"
+}
+
proc test_inaccessible_watchpoint {} {
global gdb_prompt
@@ -638,7 +650,8 @@ proc test_inaccessible_watchpoint {} {
}
gdb_test "watch *global_ptr" ".*atchpoint \[0-9\]+: \\*global_ptr"
- gdb_test "next" ".*global_ptr = buf.*"
+ gdb_test "set \$global_ptr_breakpoint_number = \$bpnum" ""
+ gdb_test "next" ".*global_ptr = buf.*" "global_ptr next"
gdb_test_multiple "next" "next over ptr init" {
-re ".*atchpoint \[0-9\]+: \\*global_ptr\r\n\r\nOld value = .*\r\nNew value = 3 .*\r\n.*$gdb_prompt $" {
# We can not test for <unknown> here because NULL may be readable.
@@ -651,6 +664,14 @@ proc test_inaccessible_watchpoint {} {
pass "next over buffer set"
}
}
+ gdb_test "delete \$global_ptr_breakpoint_number" ""
+ gdb_test "watch **global_ptr_ptr" ".*atchpoint \[0-9\]+: \\*\\*global_ptr_ptr"
+ gdb_test "set \$global_ptr_ptr_breakpoint_number = \$bpnum" ""
+ gdb_test "next" ".*global_ptr_ptr = &global_ptr.*" "gloabl_ptr_ptr next"
+ gdb_test "next" ".*atchpoint \[0-9\]+: \\*\\*global_ptr_ptr\[\r\n\]+Old value = .*\r\nNew value = 7 .*" "next over global_ptr_ptr init"
+ gdb_test "next" ".*atchpoint \[0-9\]+: \\*\\*global_ptr_ptr\[\r\n\]+Old value = 7 .*\r\nNew value = 9 .*" "next over global_ptr_ptr buffer set"
+ gdb_test "next" ".*atchpoint \[0-9\]+: \\*\\*global_ptr_ptr\[\r\n\]+Old value = 9 .*\r\nNew value = 5 .*" "next over global_ptr_ptr pointer advance"
+ gdb_test_no_output "delete \$global_ptr_ptr_breakpoint_number"
}
}
@@ -827,6 +848,13 @@ if [initialize] then {
test_watchpoint_and_breakpoint
test_watchpoint_in_big_blob
+
+ # See above.
+ if [istarget "mips-idt-*"] then {
+ clean_restart
+ }
+
+ test_constant_watchpoint
}
# Restore old timeout
diff --git a/gdb/testsuite/gdb.dwarf2/watch-notconst.c b/gdb/testsuite/gdb.dwarf2/watch-notconst.c
new file mode 100644
index 0000000..b500fc4
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/watch-notconst.c
@@ -0,0 +1,39 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2010 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 <http://www.gnu.org/licenses/>. */
+
+/* This program will be compiled with watch-notconst2.S in order to generate a
+ single binary.
+
+ The purpose of this test is to see if GDB can still watch the
+ variable `x' (define in watch-notconst2.c:f) even when we compile
+ the program using -O2 optimization. */
+
+int
+g (int j)
+{
+ int l = j + 2;
+ return l;
+}
+
+extern int f (int i);
+
+int
+main (int argc, char **argv)
+{
+ f (1);
+ return 0;
+}
diff --git a/gdb/testsuite/gdb.dwarf2/watch-notconst.exp b/gdb/testsuite/gdb.dwarf2/watch-notconst.exp
new file mode 100644
index 0000000..e0b3d33
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/watch-notconst.exp
@@ -0,0 +1,44 @@
+# Copyright 2010 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 <http://www.gnu.org/licenses/>.
+
+set test "watch-notconst"
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+# For now pick a sampling of likely targets.
+if {![istarget *-*-linux*]
+ && ![istarget *-*-gnu*]
+ && ![istarget *-*-elf*]
+ && ![istarget *-*-openbsd*]
+ && ![istarget arm-*-eabi*]
+ && ![istarget powerpc-*-eabi*]} {
+ return 0
+}
+
+# This test can only be run on x86 targets.
+if { ![istarget i?86-*] } {
+ return 0
+}
+
+if { [prepare_for_testing "${test}.exp" "${test}" \
+ {watch-notconst.c watch-notconst2.S} {nodebug}] } {
+ return -1
+}
+
+if { ![runto f] } {
+ perror "Could not run to breakpoint `f'."
+ continue
+}
+
+gdb_test "watch x" ".*\[Ww\]atchpoint 2: x" "watch x"
diff --git a/gdb/testsuite/gdb.dwarf2/watch-notconst2.S b/gdb/testsuite/gdb.dwarf2/watch-notconst2.S
new file mode 100644
index 0000000..fb99314
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/watch-notconst2.S
@@ -0,0 +1,255 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2010 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 <http://www.gnu.org/licenses/>. */
+
+/* This source file was generated from watch-notconst2.c using the following
+ command line:
+
+ gcc -m32 -dA -S -g -O2 watch-notconst2.c -o watch-notconst2.S
+
+*/
+
+ .file "watch-notconst2.c"
+ .section .debug_abbrev,"",@progbits
+.Ldebug_abbrev0:
+ .section .debug_info,"",@progbits
+.Ldebug_info0:
+ .section .debug_line,"",@progbits
+.Ldebug_line0:
+ .text
+.Ltext0:
+ .cfi_sections .debug_frame
+ .p2align 4,,15
+.globl f
+ .type f, @function
+f:
+.LFB0:
+ .file 1 "watch-notconst2.c"
+ # watch-notconst2.c:30
+ .loc 1 30 0
+ .cfi_startproc
+.LVL0:
+ # basic block 2
+ pushl %ebp
+ .cfi_def_cfa_offset 8
+ movl %esp, %ebp
+ .cfi_offset 5, -8
+ .cfi_def_cfa_register 5
+ pushl %ebx
+ subl $20, %esp
+ # watch-notconst2.c:30
+ .loc 1 30 0
+ movl 8(%ebp), %ebx
+ .cfi_offset 3, -12
+ # watch-notconst2.c:32
+ .loc 1 32 0
+ movl $2, (%esp)
+ call g
+.LVL1:
+ # watch-notconst2.c:34
+ .loc 1 34 0
+ movl %ebx, 8(%ebp)
+ # watch-notconst2.c:35
+ .loc 1 35 0
+ addl $20, %esp
+ popl %ebx
+ .cfi_restore 3
+ popl %ebp
+ .cfi_restore 5
+ .cfi_def_cfa 4, 4
+.LVL2:
+ # watch-notconst2.c:34
+ .loc 1 34 0
+ jmp g
+ .cfi_endproc
+.LFE0:
+ .size f, .-f
+.Letext0:
+ .section .debug_loc,"",@progbits
+.Ldebug_loc0:
+.LLST0:
+ .long .LVL0-.Ltext0 # Location list begin address (*.LLST0)
+ .long .LVL1-.Ltext0 # Location list end address (*.LLST0)
+ .value 0x2 # Location expression size
+ .byte 0x35 # DW_OP_lit5
+ .byte 0x9f # DW_OP_stack_value
+ .long .LVL1-.Ltext0 # Location list begin address (*.LLST0)
+ .long .LVL2-.Ltext0 # Location list end address (*.LLST0)
+ .value 0x1 # Location expression size
+ .byte 0x53 # DW_OP_reg3
+ .long 0x0 # Location list terminator begin (*.LLST0)
+ .long 0x0 # Location list terminator end (*.LLST0)
+ .section .debug_info
+ .long 0x5c # Length of Compilation Unit Info
+ .value 0x3 # DWARF version number
+ .long .Ldebug_abbrev0 # Offset Into Abbrev. Section
+ .byte 0x4 # Pointer Size (in bytes)
+ .uleb128 0x1 # (DIE (0xb) DW_TAG_compile_unit)
+ .long .LASF0 # DW_AT_producer: "GNU C 4.4.3 20100127 (Red Hat 4.4.3-4)"
+ .byte 0x1 # DW_AT_language
+ .long .LASF1 # DW_AT_name: "watch-notconst2.c"
+ .long .LASF2 # DW_AT_comp_dir: "/home/sergio/work/src/git/gdb-src/gdb/testsuite/gdb.base"
+ .long .Ltext0 # DW_AT_low_pc
+ .long .Letext0 # DW_AT_high_pc
+ .long .Ldebug_line0 # DW_AT_stmt_list
+ .uleb128 0x2 # (DIE (0x25) DW_TAG_subprogram)
+ .byte 0x1 # DW_AT_external
+ .ascii "f\0" # DW_AT_name
+ .byte 0x1 # DW_AT_decl_file (watch-notconst2.c)
+ .byte 0x1d # DW_AT_decl_line
+ .byte 0x1 # DW_AT_prototyped
+ .long 0x58 # DW_AT_type
+ .long .LFB0 # DW_AT_low_pc
+ .long .LFE0 # DW_AT_high_pc
+ .byte 0x1 # DW_AT_frame_base
+ .byte 0x9c # DW_OP_call_frame_cfa
+ .long 0x58 # DW_AT_sibling
+ .uleb128 0x3 # (DIE (0x3e) DW_TAG_formal_parameter)
+ .ascii "i\0" # DW_AT_name
+ .byte 0x1 # DW_AT_decl_file (watch-notconst2.c)
+ .byte 0x1d # DW_AT_decl_line
+ .long 0x58 # DW_AT_type
+ .byte 0x2 # DW_AT_location
+ .byte 0x91 # DW_OP_fbreg
+ .sleb128 0
+ .uleb128 0x4 # (DIE (0x4a) DW_TAG_variable)
+ .ascii "x\0" # DW_AT_name
+ .byte 0x1 # DW_AT_decl_file (watch-notconst2.c)
+ .byte 0x1f # DW_AT_decl_line
+ .long 0x58 # DW_AT_type
+ .long .LLST0 # DW_AT_location
+ .byte 0x0 # end of children of DIE 0x25
+ .uleb128 0x5 # (DIE (0x58) DW_TAG_base_type)
+ .byte 0x4 # DW_AT_byte_size
+ .byte 0x5 # DW_AT_encoding
+ .ascii "int\0" # DW_AT_name
+ .byte 0x0 # end of children of DIE 0xb
+ .section .debug_abbrev
+ .uleb128 0x1 # (abbrev code)
+ .uleb128 0x11 # (TAG: DW_TAG_compile_unit)
+ .byte 0x1 # DW_children_yes
+ .uleb128 0x25 # (DW_AT_producer)
+ .uleb128 0xe # (DW_FORM_strp)
+ .uleb128 0x13 # (DW_AT_language)
+ .uleb128 0xb # (DW_FORM_data1)
+ .uleb128 0x3 # (DW_AT_name)
+ .uleb128 0xe # (DW_FORM_strp)
+ .uleb128 0x1b # (DW_AT_comp_dir)
+ .uleb128 0xe # (DW_FORM_strp)
+ .uleb128 0x11 # (DW_AT_low_pc)
+ .uleb128 0x1 # (DW_FORM_addr)
+ .uleb128 0x12 # (DW_AT_high_pc)
+ .uleb128 0x1 # (DW_FORM_addr)
+ .uleb128 0x10 # (DW_AT_stmt_list)
+ .uleb128 0x6 # (DW_FORM_data4)
+ .byte 0x0
+ .byte 0x0
+ .uleb128 0x2 # (abbrev code)
+ .uleb128 0x2e # (TAG: DW_TAG_subprogram)
+ .byte 0x1 # DW_children_yes
+ .uleb128 0x3f # (DW_AT_external)
+ .uleb128 0xc # (DW_FORM_flag)
+ .uleb128 0x3 # (DW_AT_name)
+ .uleb128 0x8 # (DW_FORM_string)
+ .uleb128 0x3a # (DW_AT_decl_file)
+ .uleb128 0xb # (DW_FORM_data1)
+ .uleb128 0x3b # (DW_AT_decl_line)
+ .uleb128 0xb # (DW_FORM_data1)
+ .uleb128 0x27 # (DW_AT_prototyped)
+ .uleb128 0xc # (DW_FORM_flag)
+ .uleb128 0x49 # (DW_AT_type)
+ .uleb128 0x13 # (DW_FORM_ref4)
+ .uleb128 0x11 # (DW_AT_low_pc)
+ .uleb128 0x1 # (DW_FORM_addr)
+ .uleb128 0x12 # (DW_AT_high_pc)
+ .uleb128 0x1 # (DW_FORM_addr)
+ .uleb128 0x40 # (DW_AT_frame_base)
+ .uleb128 0xa # (DW_FORM_block1)
+ .uleb128 0x1 # (DW_AT_sibling)
+ .uleb128 0x13 # (DW_FORM_ref4)
+ .byte 0x0
+ .byte 0x0
+ .uleb128 0x3 # (abbrev code)
+ .uleb128 0x5 # (TAG: DW_TAG_formal_parameter)
+ .byte 0x0 # DW_children_no
+ .uleb128 0x3 # (DW_AT_name)
+ .uleb128 0x8 # (DW_FORM_string)
+ .uleb128 0x3a # (DW_AT_decl_file)
+ .uleb128 0xb # (DW_FORM_data1)
+ .uleb128 0x3b # (DW_AT_decl_line)
+ .uleb128 0xb # (DW_FORM_data1)
+ .uleb128 0x49 # (DW_AT_type)
+ .uleb128 0x13 # (DW_FORM_ref4)
+ .uleb128 0x2 # (DW_AT_location)
+ .uleb128 0xa # (DW_FORM_block1)
+ .byte 0x0
+ .byte 0x0
+ .uleb128 0x4 # (abbrev code)
+ .uleb128 0x34 # (TAG: DW_TAG_variable)
+ .byte 0x0 # DW_children_no
+ .uleb128 0x3 # (DW_AT_name)
+ .uleb128 0x8 # (DW_FORM_string)
+ .uleb128 0x3a # (DW_AT_decl_file)
+ .uleb128 0xb # (DW_FORM_data1)
+ .uleb128 0x3b # (DW_AT_decl_line)
+ .uleb128 0xb # (DW_FORM_data1)
+ .uleb128 0x49 # (DW_AT_type)
+ .uleb128 0x13 # (DW_FORM_ref4)
+ .uleb128 0x2 # (DW_AT_location)
+ .uleb128 0x6 # (DW_FORM_data4)
+ .byte 0x0
+ .byte 0x0
+ .uleb128 0x5 # (abbrev code)
+ .uleb128 0x24 # (TAG: DW_TAG_base_type)
+ .byte 0x0 # DW_children_no
+ .uleb128 0xb # (DW_AT_byte_size)
+ .uleb128 0xb # (DW_FORM_data1)
+ .uleb128 0x3e # (DW_AT_encoding)
+ .uleb128 0xb # (DW_FORM_data1)
+ .uleb128 0x3 # (DW_AT_name)
+ .uleb128 0x8 # (DW_FORM_string)
+ .byte 0x0
+ .byte 0x0
+ .byte 0x0
+ .section .debug_pubnames,"",@progbits
+ .long 0x14 # Length of Public Names Info
+ .value 0x2 # DWARF Version
+ .long .Ldebug_info0 # Offset of Compilation Unit Info
+ .long 0x60 # Compilation Unit Length
+ .long 0x25 # DIE offset
+ .ascii "f\0" # external name
+ .long 0x0
+ .section .debug_aranges,"",@progbits
+ .long 0x1c # Length of Address Ranges Info
+ .value 0x2 # DWARF Version
+ .long .Ldebug_info0 # Offset of Compilation Unit Info
+ .byte 0x4 # Size of Address
+ .byte 0x0 # Size of Segment Descriptor
+ .value 0x0 # Pad to 8 byte boundary
+ .value 0x0
+ .long .Ltext0 # Address
+ .long .Letext0-.Ltext0 # Length
+ .long 0x0
+ .long 0x0
+ .section .debug_str,"MS",@progbits,1
+.LASF1:
+ .string "watch-notconst2.c"
+.LASF2:
+ .string ""
+.LASF0:
+ .string "GNU C 4.4.3 20100127 (Red Hat 4.4.3-4)"
+ .ident "GCC: (GNU) 4.4.3 20100127 (Red Hat 4.4.3-4)"
+ .section .note.GNU-stack,"",@progbits
diff --git a/gdb/testsuite/gdb.dwarf2/watch-notconst2.c b/gdb/testsuite/gdb.dwarf2/watch-notconst2.c
new file mode 100644
index 0000000..4a70f8d
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/watch-notconst2.c
@@ -0,0 +1,35 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2010 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 <http://www.gnu.org/licenses/>. */
+
+/* The original program corresponding to watch-notconst2.S.
+
+ This program is not compiled; the .S version is used instead.
+
+ The purpose of this test is to see if GDB can still watch the
+ variable `x' even when we compile the program using -O2
+ optimization. */
+
+extern int g (int j);
+
+int
+f (int i)
+{
+ int x = 5;
+ g (2);
+ x = i;
+ return g (x);
+}