[lldb-dev] "target modules load" and breakpoints not working correctly

[Ted Woodward via lldb-dev]

Your guess is right - the sections moved. Before attaching:

  0x00000008 code             [0x0000000000030000-0x0000000000068d5c)  0x00011000 0x00038d5c 0x00000006 dlopen..text

After attaching:

  0x00000008 code             [0x0000000000010000-0x0000000000048d5c)  0x00011000 0x00038d5c 0x00000006 dlopen..text

--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

-----Original Message-----
From: Greg Clayton [mailto:gclayton at apple.com] 
Sent: Thursday, March 17, 2016 12:44 PM
To: Ted Woodward <ted.woodward at codeaurora.org>
Cc: LLDB <lldb-dev at lists.llvm.org>
Subject: Re: [lldb-dev] "target modules load" and breakpoints not working correctly

Sounds like something is going wrong when resolving the address. I am guessing that your sections got unloaded when you attached to your GDB remote target. So try this:

(lldb) file u:\lldb_test\dlopen
Current executable set to 'u:\lldb_test\dlopen' (hexagon).
(lldb) target modules load -f dlopen -s 0x20000
(lldb) b main
Breakpoint 1: where = dlopen`main + 24 at dlopen.c:26, address = 0x00030018

Note we got the address correct. Now do a:

(lldb) image dump sections dlopen

Check to make sure all addresses for the sections look good.

Now do:

(lldb) gdb-remote tedwood-ubuntu:5556
(lldb) image dump sections dlopen

I am guessing that the sections have been moved...

Let me know what you find.

> On Mar 16, 2016, at 4:28 PM, Ted Woodward via lldb-dev <lldb-dev at lists.llvm.org> wrote:
> 
> I’m seeing 2 issues with “target modules load”:
>  
>  
>  
> Issue #1: load address is forgotten after a connect:
>  
> (lldb) file u:\lldb_test\dlopen
> Current executable set to 'u:\lldb_test\dlopen' (hexagon).
> (lldb) target modules load -f dlopen -s 0x20000
> (lldb) b main
> Breakpoint 1: where = dlopen`main + 24 at dlopen.c:26, address = 
> 0x00030018
> (lldb) gdb-remote tedwood-ubuntu:5556
>  
> But it’s set the breakpoint at 0x10018 instead of 0x30018:
> ProcessGDBRemote::EnableBreakpointSite (size_id = 14) address = 
> 0x10018 <  14> send packet: $Z0,10018,4#10
> <   4> read packet: $#00
> Software breakpoints are unsupported
> <  14> send packet: $Z1,10018,4#11
> <   6> read packet: $OK#9a
>  
> (lldb) br l
> Current breakpoints:
> 1: name = 'main', locations = 1, resolved = 1, hit count = 0
>   1.1: where = dlopen`main + 24 at dlopen.c:26, address = 0x00010018, 
> resolved, hit count = 0
>  
>  
>  
>  
> Issue #2: breakpoints on the remote server aren’t updated with a new load address, even though they’re updated in the breakpoint list:
>  
> (lldb) br l
> Current breakpoints:
> 1: name = 'main', locations = 1, resolved = 1, hit count = 0
>   1.1: where = dlopen`main + 24 at dlopen.c:26, address = 0x00010018, 
> resolved, hit count = 0
>  
> (lldb) target modules load -f dlopen -s 0x20000
> (lldb) br l
> <   7> send packet: $p29#db
> <  12> read packet: $00100000#81
> <   7> send packet: $p1d#05
> <  12> read packet: $00000000#80
> Current breakpoints:
> 1: name = 'main', locations = 1, resolved = 1, hit count = 0
>   1.1: where = dlopen`main + 24 at dlopen.c:26, address = 0x00030018, 
> resolved, hit count = 0
>  
> (lldb) c
> Process 1 stopped
> * thread #1: tid = 0x0001, 0x00030018 dlopen`main(argc=1, 
> argv=0x00052348) + 24 at dlopen.c:26, stop reason = breakpoint 1.1
>     frame #0: 0x00030018 dlopen`main(argc=1, argv=0x00052348) + 24 at 
> dlopen.c:26
>  
> (lldb) re r pc
>       pc = 0x00010018  dlopen`main + 24 at dlopen.c:26
>  
> Note that lldb says it’s stopped at 0x30018, but it’s really stopped at 0x10018. It never sent a z packet to remove the breakpoint at 0x10018 or a Z packet to add one at 0x30018.
>  
> --
> Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, 
> a Linux Foundation Collaborative Project
>  
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