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Clear non-significant bits of address in watchpoint

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Nowadays, GDB can't set watchpoint on tagged address on AArch64,

(gdb) p p2
$1 = (int *) 0xf000fffffffff474
(gdb) watch *((int *) 0xf000fffffffff474)
Hardware watchpoint 2: *((int *) 0xf000fffffffff474)
(gdb) c
Continuing.
main () at
binutils-gdb/gdb/testsuite/gdb.arch/aarch64-tagged-pointer.c:45
45	  void (*func_ptr) (void) = foo;
Unexpected error setting hardware debug registers

This patch is about setting watchpoint on a tagged address.  Unlike
breakpoint, watchpoint record the expression rather than the address, and
when a watchpoint is fired, GDB checks the expression value changed
instead of matching address, so we can mask the watchpoint address by
getting rid of non-significant bits of address.

gdb:

2017-12-08  Yao Qi  <yao.qi@linaro.org>

	* breakpoint.c (update_watchpoint): Call
	address_significant.

gdb/testsuite:

2017-12-08  Yao Qi  <yao.qi@linaro.org>

	* gdb.arch/aarch64-tagged-pointer.c (main): Update.
	* gdb.arch/aarch64-tagged-pointer.exp: Add tests for watchpoint.
This commit is contained in:
Yao Qi 2017-12-08 17:27:03 +00:00
parent a0de8c21ba
commit f17d947477
5 changed files with 26 additions and 1 deletions
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5
gdb/ChangeLog
View file

@ -1,3 +1,8 @@
2017-12-08 Yao Qi <yao.qi@linaro.org>
* breakpoint.c (update_watchpoint): Call
address_significant.
2017-12-08 Yao Qi <yao.qi@linaro.org>
* breakpoint.c (adjust_breakpoint_address): Call

2
gdb/breakpoint.c
View file

@ -1864,7 +1864,7 @@ update_watchpoint (struct watchpoint *b, int reparse)
loc->gdbarch = get_type_arch (value_type (v));
loc->pspace = frame_pspace;
loc->address = addr;
loc->address = address_significant (loc->gdbarch, addr);
if (bitsize != 0)
{

5
gdb/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2017-12-08 Yao Qi <yao.qi@linaro.org>
* gdb.arch/aarch64-tagged-pointer.c (main): Update.
* gdb.arch/aarch64-tagged-pointer.exp: Add tests for watchpoint.
2017-12-08 Yao Qi <yao.qi@linaro.org>
* gdb.arch/aarch64-tagged-pointer.c (main): Update.

1
gdb/testsuite/gdb.arch/aarch64-tagged-pointer.c
View file

@ -53,4 +53,5 @@ main (void)
}
sp1->i = 8765;
i = 1;
}

14
gdb/testsuite/gdb.arch/aarch64-tagged-pointer.exp
View file

@ -89,3 +89,17 @@ foreach_with_prefix bptype {"hbreak" "break"} {
gdb_test "up" "\\(\*func_ptr\\) \\(\\).*" "caller is *func_ptr"
delete_breakpoints
}
gdb_test "down"
gdb_test "finish"
# Watch on tagged pointer.
gdb_test "watch *sp2"
gdb_test "continue" \
"Continuing\\..*Hardware watchpoint \[0-9\]+.*" \
"run until watchpoint on s1"
delete_breakpoints
gdb_test "watch *p2"
gdb_test "continue" \
"Continuing\\..*Hardware watchpoint \[0-9\]+.*" \
"run until watchpoint on i"