From 31e77af205cf6564c2bf4c18400b4ca16bdf92cd Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Thu, 20 Mar 2014 13:26:32 +0000 Subject: PR breakpoints/7143 - Watchpoint does not trigger when first set Say the program is stopped at a breakpoint, and the user sets a watchpoint. When the program is next resumed, GDB will first step over the breakpoint, as explained in the manual: @value {GDBN} normally ignores breakpoints when it resumes execution, until at least one instruction has been executed. If it it did not do this, you would be unable to proceed past a breakpoint without first disabling the breakpoint. This rule applies whether or not the breakpoint already existed when your program stopped. However, GDB currently also removes watchpoints, catchpoints, etc., and that means that the first instruction off the breakpoint does not trigger the watchpoint, catchpoint, etc. testsuite/gdb.base/watchpoint.exp has a kfail for this. The PR proposes installing watchpoints only when stepping over a breakpoint, but that misses catchpoints, etc. A better fix would instead work from the opposite direction -- remove only real breakpoints, leaving all other kinds of breakpoints inserted. But, going further, it's really a waste to constantly remove/insert all breakpoints when stepping over a single breakpoint (generating a pair of RSP z/Z packets for each breakpoint), so the fix goes a step further and makes GDB remove _only_ the breakpoint being stepped over, leaving all others installed. This then has the added benefit of reducing breakpoint-related RSP traffic substancialy when there are many breakpoints set. gdb/ 2014-03-20 Pedro Alves PR breakpoints/7143 * breakpoint.c (should_be_inserted): Don't insert breakpoints that are being stepped over. (breakpoint_address_match): Make extern. * breakpoint.h (breakpoint_address_match): New declaration. * inferior.h (stepping_past_instruction_at): New declaration. * infrun.c (struct step_over_info): New type. (step_over_info): New global. (set_step_over_info, clear_step_over_info) (stepping_past_instruction_at): New functions. (handle_inferior_event): Clear the step-over info when trap_expected is cleared. (resume): Remove now stale comment. (clear_proceed_status): Clear step-over info. (proceed): Adjust step-over handling to set or clear the step-over info instead of removing all breakpoints. (handle_signal_stop): When setting up a thread-hop, don't remove breakpoints here. (stop_stepping): Clear step-over info. (keep_going): Adjust step-over handling to set or clear step-over info and then always inserting breakpoints, instead of removing all breakpoints when stepping over one. gdb/testsuite/ 2014-03-20 Pedro Alves PR breakpoints/7143 * gdb.base/watchpoint.exp: Mention bugzilla bug number instead of old gnats gdb/38. Remove kfail. Adjust to use gdb_test instead of gdb_test_multiple. * gdb.cp/annota2.exp: Remove kfail for gdb/38. * gdb.cp/annota3.exp: Remove kfail for gdb/38. --- gdb/testsuite/gdb.cp/annota2.exp | 3 --- 1 file changed, 3 deletions(-) (limited to 'gdb/testsuite/gdb.cp/annota2.exp') diff --git a/gdb/testsuite/gdb.cp/annota2.exp b/gdb/testsuite/gdb.cp/annota2.exp index 00a6067..6fbf4b5 100644 --- a/gdb/testsuite/gdb.cp/annota2.exp +++ b/gdb/testsuite/gdb.cp/annota2.exp @@ -165,9 +165,6 @@ gdb_test_multiple "next" "watch triggered on a.x" { -re "\r\n\032\032post-prompt\r\n\r\n\032\032starting\r\n${frames_invalid}${breakpoints_invalid}\r\n\032\032watchpoint 3\r\n.*atchpoint 3: a.x\r\n\r\nOld value = 0\r\nNew value = 1\r\n\r\n\032\032frame-begin 0 $hex\r\n\r\n\032\032frame-function-name\r\nmain\r\n\032\032frame-args\r\n \\(\\)\r\n\032\032frame-source-begin\r\n at \r\n\032\032frame-source-file\r\n.*$srcfile\r\n\032\032frame-source-file-end\r\n:\r\n\032\032frame-source-line\r\n$decimal\r\n\032\032frame-source-end\r\n\r\n\r\n\032\032source .*$srcfile.*beg:$hex\r\n\r\n\032\032frame-end\r\n\r\n\032\032stopped\r\n.*$gdb_prompt$" { pass "watch triggered on a.x" } - -re "\r\n\032\032post-prompt\r\n\r\n\032\032starting\r\n${frames_invalid}\r\n\032\032source .*$srcfile.*beg:$hex\r\n\r\n\032\032frame-end\r\n\r\n\032\032stopped\r\n$gdb_prompt$" { - kfail "gdb/38" "watch triggered on a.x" - } } -- cgit v1.1