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Joan Lluch via llvm-dev

2019-Nov-04 20:29 UTC

[llvm-dev] Debugging clang with debugger breakpoints ?

Hi David,

Thank you for your help. Please, can you elaborate on this?. The command line
that I get with -### starts with this:

clang version 9.0.1 (https://github.com/llvm/llvm-project.git
6e38ee067b8fa08792f551fb565bbb8ada4864b1)
Target: msp430
Thread model: posix
InstalledDir: /Users/joan/LLVM-9/llvm-project/build/Debug/bin
 "/Users/joan/LLVM-9/llvm-project/build/Debug/bin/clang"
"-cc1" "-triple" "msp430" "-emit-llvm"
"-disable-free" "-main-file-name" "main.c"
"-mrelocation-model" "static" "-mthread-model"
"posix" "-fmath-errno" "-masm-verbose"
"-mconstructor-aliases" "-nostdsysteminc"
"-dwarf-column-info" "-debugger-tuning=gdb"
"-target-linker-version" "305"
"-momit-leaf-frame-pointer" "-coverage-notes-file"
"/Users/joan/Documents-Local/Relay/RelayNou/main.gcno"
"-resource-dir"
"/Users/joan/LLVM-9/llvm-project/build/Debug/lib/clang/9.0.1"
"-internal-isystem"
"/Users/joan/LLVM-9/llvm-project/build/Debug/bin/../msp430/include"
"-Oz" "-fdebug-compilation-dir"
"/Users/joan/Documents-Local/Relay/RelayNou" "-ferror-limit"
"19" "-fmessage-length" "224"
"-fobjc-runtime=gcc" "-fdiagnostics-show-option"
"-fcolor-diagnostics" "-vectorize-slp" "-faddrsig"
"-o" "main.ll" "-x" "c"
"main.c"

So what should I set on the debugger?

Thanks

John





> On 4 Nov 2019, at 21:03, David Blaikie <dblaikie at gmail.com> wrote:
> 
> Run clang with -### to get the underlying command line (the one that has
the first argument "-cc1") and then run that command under the
debugger instead.
> 
> On Mon, Nov 4, 2019 at 12:02 PM Joan Lluch via llvm-dev <llvm-dev at
lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
> Hi All,
> 
> I want to understand some parts of ‘clang' by setting debug
breakpoints.
> 
> I have successfully done so with “llc” but I found that debugger
breakpoints do not work for ‘clang’
> 
> The apparent cause is that the clang code is run as a child process which
is created in the ‘Execute' function of ‘Program.inc'. The debugger
stops fine at breakpoints set on the main thread, but breakpoints do not work
for any code that is executed as the child process. I am compiling with Xcode in
case this makes a difference.
> 
> Thanks in advance for any help.
> 
> John
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
<https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev>
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David Blaikie via llvm-dev

2019-Nov-04 20:43 UTC

head link

[llvm-dev] Debugging clang with debugger breakpoints ?

that command:

"/Users/joan/LLVM-9/llvm-project/build/Debug/bin/clang"
"-cc1" "-triple"
"msp430" "-emit-llvm" "-disable-free"
"-main-file-name" "main.c"
"-mrelocation-model" "static" "-mthread-model"
"posix" "-fmath-errno"
"-masm-verbose" "-mconstructor-aliases"
"-nostdsysteminc"
"-dwarf-column-info" "-debugger-tuning=gdb"
"-target-linker-version" "305"
"-momit-leaf-frame-pointer" "-coverage-notes-file"
"/Users/joan/Documents-Local/Relay/RelayNou/main.gcno"
"-resource-dir"
"/Users/joan/LLVM-9/llvm-project/build/Debug/lib/clang/9.0.1"
"-internal-isystem"
"/Users/joan/LLVM-9/llvm-project/build/Debug/bin/../msp430/include"
"-Oz"
"-fdebug-compilation-dir"
"/Users/joan/Documents-Local/Relay/RelayNou"
"-ferror-limit" "19" "-fmessage-length"
"224" "-fobjc-runtime=gcc"
"-fdiagnostics-show-option" "-fcolor-diagnostics"
"-vectorize-slp"
"-faddrsig" "-o" "main.ll" "-x"
"c" "main.c"

Or wherever you had: -emit-llvm -S -g main.c (or something like that)
You now have:  "-cc1" "-triple" "msp430"
"-emit-llvm" "-disable-free"
"-main-file-name" "main.c" "-mrelocation-model"
"static" "-mthread-model"
"posix" "-fmath-errno" "-masm-verbose"
"-mconstructor-aliases"
"-nostdsysteminc" "-dwarf-column-info"
"-debugger-tuning=gdb"
"-target-linker-version" "305"
"-momit-leaf-frame-pointer"
"-coverage-notes-file"
"/Users/joan/Documents-Local/Relay/RelayNou/main.gcno"
"-resource-dir"
"/Users/joan/LLVM-9/llvm-project/build/Debug/lib/clang/9.0.1"
"-internal-isystem"
"/Users/joan/LLVM-9/llvm-project/build/Debug/bin/../msp430/include"
"-Oz"
"-fdebug-compilation-dir"
"/Users/joan/Documents-Local/Relay/RelayNou"
"-ferror-limit" "19" "-fmessage-length"
"224" "-fobjc-runtime=gcc"
"-fdiagnostics-show-option" "-fcolor-diagnostics"
"-vectorize-slp"
"-faddrsig" "-o" "main.ll" "-x"
"c" "main.c"


On Mon, Nov 4, 2019 at 12:29 PM Joan Lluch <joan.lluch at icloud.com>
wrote:
> Hi David,
>
> Thank you for your help. Please, can you elaborate on this?. The command
> line that I get with -### starts with this:
>
> clang version 9.0.1 (https://github.com/llvm/llvm-project.git
> 6e38ee067b8fa08792f551fb565bbb8ada4864b1)
> Target: msp430
> Thread model: posix
> InstalledDir: /Users/joan/LLVM-9/llvm-project/build/Debug/bin
>  "/Users/joan/LLVM-9/llvm-project/build/Debug/bin/clang"
"-cc1" "-triple"
> "msp430" "-emit-llvm" "-disable-free"
"-main-file-name" "main.c"
> "-mrelocation-model" "static"
"-mthread-model" "posix" "-fmath-errno"
> "-masm-verbose" "-mconstructor-aliases"
"-nostdsysteminc"
> "-dwarf-column-info" "-debugger-tuning=gdb"
"-target-linker-version" "305"
> "-momit-leaf-frame-pointer" "-coverage-notes-file"
> "/Users/joan/Documents-Local/Relay/RelayNou/main.gcno"
"-resource-dir"
> "/Users/joan/LLVM-9/llvm-project/build/Debug/lib/clang/9.0.1"
> "-internal-isystem"
>
"/Users/joan/LLVM-9/llvm-project/build/Debug/bin/../msp430/include"
"-Oz"
> "-fdebug-compilation-dir"
"/Users/joan/Documents-Local/Relay/RelayNou"
> "-ferror-limit" "19" "-fmessage-length"
"224" "-fobjc-runtime=gcc"
> "-fdiagnostics-show-option" "-fcolor-diagnostics"
"-vectorize-slp"
> "-faddrsig" "-o" "main.ll" "-x"
"c" "main.c"
>
> So what should I set on the debugger?
>
> Thanks
>
> John
>
>
>
>
>
>
> On 4 Nov 2019, at 21:03, David Blaikie <dblaikie at gmail.com> wrote:
>
> Run clang with -### to get the underlying command line (the one that has
> the first argument "-cc1") and then run that command under the
debugger
> instead.
>
> On Mon, Nov 4, 2019 at 12:02 PM Joan Lluch via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Hi All,
>>
>> I want to understand some parts of ‘clang' by setting debug
breakpoints.
>>
>> I have successfully done so with “llc” but I found that debugger
>> breakpoints do not work for ‘clang’
>>
>> The apparent cause is that the clang code is run as a child process
which
>> is created in the ‘Execute' function of ‘Program.inc'. The
debugger stops
>> fine at breakpoints set on the main thread, but breakpoints do not work
for
>> any code that is executed as the child process. I am compiling with
Xcode
>> in case this makes a difference.
>>
>> Thanks in advance for any help.
>>
>> John
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>
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Joan Lluch via llvm-dev

2019-Nov-04 21:10 UTC

head link

[llvm-dev] Debugging clang with debugger breakpoints ?

Hi David,

Thank you for your patience but I still don’t get it:  I don’t see how that is a
“command”, as it’s just a list of strings that state command options.

I know how to use the debugger, this is what I attempt to debug:

 clang --target=msp430 -emit-llvm -c -S -Oz main.c   

The debugger works fine, but only on the main thread. However breakpoints do not
work with the code that was invoked as a child process with posix_spawn

The call to posix_spawn happens in file “Program.inc” on the ‘Execute'
function. The actual call is this

Err = posix_spawn(&PID, Program.str().c_str(), FileActions,
                        /*attrp*/ nullptr, const_cast<char **>(Argv),
                        const_cast<char **>(Envp));

the variable Program.str() contains
"/Users/joan/LLVM-9/llvm-project/build/Debug/bin/clang” at this point,
which I got with a breakpoint set at that point.

HOWEVER, any code that is run under that child process is not seen by the
debugger.

I hope my issue is clearer now.

Thanks anyway.

John

> On 4 Nov 2019, at 21:43, David Blaikie <dblaikie at gmail.com> wrote:
> 
> that command:
> 
> "/Users/joan/LLVM-9/llvm-project/build/Debug/bin/clang"
"-cc1" "-triple" "msp430" "-emit-llvm"
"-disable-free" "-main-file-name" "main.c"
"-mrelocation-model" "static" "-mthread-model"
"posix" "-fmath-errno" "-masm-verbose"
"-mconstructor-aliases" "-nostdsysteminc"
"-dwarf-column-info" "-debugger-tuning=gdb"
"-target-linker-version" "305"
"-momit-leaf-frame-pointer" "-coverage-notes-file"
"/Users/joan/Documents-Local/Relay/RelayNou/main.gcno"
"-resource-dir"
"/Users/joan/LLVM-9/llvm-project/build/Debug/lib/clang/9.0.1"
"-internal-isystem"
"/Users/joan/LLVM-9/llvm-project/build/Debug/bin/../msp430/include"
"-Oz" "-fdebug-compilation-dir"
"/Users/joan/Documents-Local/Relay/RelayNou" "-ferror-limit"
"19" "-fmessage-length" "224"
"-fobjc-runtime=gcc" "-fdiagnostics-show-option"
"-fcolor-diagnostics" "-vectorize-slp" "-faddrsig"
"-o" "main.ll" "-x" "c"
"main.c"
> 
> Or wherever you had: -emit-llvm -S -g main.c (or something like that)
> You now have:  "-cc1" "-triple" "msp430"
"-emit-llvm" "-disable-free" "-main-file-name"
"main.c" "-mrelocation-model" "static"
"-mthread-model" "posix" "-fmath-errno"
"-masm-verbose" "-mconstructor-aliases"
"-nostdsysteminc" "-dwarf-column-info"
"-debugger-tuning=gdb" "-target-linker-version"
"305" "-momit-leaf-frame-pointer"
"-coverage-notes-file"
"/Users/joan/Documents-Local/Relay/RelayNou/main.gcno"
"-resource-dir"
"/Users/joan/LLVM-9/llvm-project/build/Debug/lib/clang/9.0.1"
"-internal-isystem"
"/Users/joan/LLVM-9/llvm-project/build/Debug/bin/../msp430/include"
"-Oz" "-fdebug-compilation-dir"
"/Users/joan/Documents-Local/Relay/RelayNou" "-ferror-limit"
"19" "-fmessage-length" "224"
"-fobjc-runtime=gcc" "-fdiagnostics-show-option"
"-fcolor-diagnostics" "-vectorize-slp" "-faddrsig"
"-o" "main.ll" "-x" "c"
"main.c"
> 
> 
> On Mon, Nov 4, 2019 at 12:29 PM Joan Lluch <joan.lluch at icloud.com
<mailto:joan.lluch at icloud.com>> wrote:
> Hi David,
> 
> Thank you for your help. Please, can you elaborate on this?. The command
line that I get with -### starts with this:
> 
> clang version 9.0.1 (https://github.com/llvm/llvm-project.git
<https://github.com/llvm/llvm-project.git>
6e38ee067b8fa08792f551fb565bbb8ada4864b1)
> Target: msp430
> Thread model: posix
> InstalledDir: /Users/joan/LLVM-9/llvm-project/build/Debug/bin
>  "/Users/joan/LLVM-9/llvm-project/build/Debug/bin/clang"
"-cc1" "-triple" "msp430" "-emit-llvm"
"-disable-free" "-main-file-name" "main.c"
"-mrelocation-model" "static" "-mthread-model"
"posix" "-fmath-errno" "-masm-verbose"
"-mconstructor-aliases" "-nostdsysteminc"
"-dwarf-column-info" "-debugger-tuning=gdb"
"-target-linker-version" "305"
"-momit-leaf-frame-pointer" "-coverage-notes-file"
"/Users/joan/Documents-Local/Relay/RelayNou/main.gcno"
"-resource-dir"
"/Users/joan/LLVM-9/llvm-project/build/Debug/lib/clang/9.0.1"
"-internal-isystem"
"/Users/joan/LLVM-9/llvm-project/build/Debug/bin/../msp430/include"
"-Oz" "-fdebug-compilation-dir"
"/Users/joan/Documents-Local/Relay/RelayNou" "-ferror-limit"
"19" "-fmessage-length" "224"
"-fobjc-runtime=gcc" "-fdiagnostics-show-option"
"-fcolor-diagnostics" "-vectorize-slp" "-faddrsig"
"-o" "main.ll" "-x" "c"
"main.c"
> 
> So what should I set on the debugger?
> 
> Thanks
> 
> John
> 
> 
> 
> 
> 
> 
>> On 4 Nov 2019, at 21:03, David Blaikie <dblaikie at gmail.com
<mailto:dblaikie at gmail.com>> wrote:
>> 
>> Run clang with -### to get the underlying command line (the one that
has the first argument "-cc1") and then run that command under the
debugger instead.
>> 
>> On Mon, Nov 4, 2019 at 12:02 PM Joan Lluch via llvm-dev <llvm-dev at
lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
>> Hi All,
>> 
>> I want to understand some parts of ‘clang' by setting debug
breakpoints.
>> 
>> I have successfully done so with “llc” but I found that debugger
breakpoints do not work for ‘clang’
>> 
>> The apparent cause is that the clang code is run as a child process
which is created in the ‘Execute' function of ‘Program.inc'. The
debugger stops fine at breakpoints set on the main thread, but breakpoints do
not work for any code that is executed as the child process. I am compiling with
Xcode in case this makes a difference.
>> 
>> Thanks in advance for any help.
>> 
>> John
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
<https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev>
> 
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