[cfe-dev] How clang works, whant to learn compiler internals

[don hinton via cfe-dev]

Try using the -### option.

$ clang --help
<...>
  -###                    Print (but do not run) the commands to run for
this compilation
<...>

On Tue, Oct 18, 2016 at 2:18 AM, Ivan Kush via cfe-dev <
cfe-dev at lists.llvm.org> wrote:

> thanks, know prints to console
>
> --
> Best wishes,
> Ivan Kush
>
>
>
> 18.10.2016, 12:02, "Alex L" <arphaman at gmail.com>:
>
>
>
> On 18 October 2016 at 09:58, Ivan Kush via cfe-dev <cfe-dev at lists.llvm.org
> > wrote:
>
> thanks a lot!
> with "-cc1" the compiler doesn't understand "-Xclang" parameter.
>
>
> -cc1 -std=c++1z -Xclang -ast-dump -fsyntax-only test_deb.cpp
>
>
> So deleted "-Xclang", but in that case AST doesn't output to console.
>
>
>
> -cc1 -std=c++1z -ast-dump -fsyntax-only test_deb.cpp
>
>
> Does someone know what parameters should pass in that case, in order to
> output AST to console?
>
>
> You don't need 'fsyntax-only' when dumping the AST, so this should work:
>
>   -cc1 -std=c++1z -ast-dump test_deb.cpp
>
>
> --
> Best wishes,
> Ivan Kush
>
>
>
> 18.10.2016, 11:12, "Serge Pavlov" <sepavloff at gmail.com>:
>
> You need to pass argument "-cc1" to the compiler in debug session. In your
> case parameters must be:
> -cc1 -std=c++1z -Xclang -ast-dump -fsyntax-only test_deb.cpp
>
> Without "-cc1" clang works as driver executing other tools to make job,
> with "-cc1" it works as compiler.
>
> Thanks,
> --Serge
>
> 2016-10-18 14:54 GMT+07:00 Ivan Kush via cfe-dev <cfe-dev at lists.llvm.org>:
>
> I want to learn clang internals and how it works. But
> llvm::sys::ExecuteAndWait executes in the debugger and that's all, finish,
> console output with my AST (I passes to clang "-ast-dump"). It didn't jump
> in the Lexer.cpp, Sema.cpp, etc. What should I do in the debugger, in order
> to see how Lexer, Sema work?
>
> My steps in the debugger:
>
> 1) compiled debug version of llvm and clang
>
> 2) created a source file "test_deb.cpp" with  the following code
>
> enum class Enum : int
> {
>     kOne,
>     kTwo
> };
>
> int f(int x) {
>   int result = (x / 42);
>   return result;
> }
>
> int main()
> {
>     return f(4);
> }
>
> 3) launch clang-4.0 in in the debugger with the following parameters:
> -std=c++1z -Xclang -ast-dump -fsyntax-only test_deb.cpp
>
> 4)  and begin to learn how all work:
> the "int main" in driver.cpp
>
> in driver.cpp is called "ExecuteCompilation" of "Driver"
>     TheDriver.ExecuteCompilation(*C, FailingCommands);
>
> where called "ExecuteJobs" of "Compilation" (the file Compilation.cpp):
>     C.ExecuteJobs(C.getJobs(), FailingCommands);
>
> in the func ExecuteJobs called ExecuteCommand
>     if (int Res = ExecuteCommand(Job, FailingCommand)) {
>
> that calls "Execute" of "Command" (the file Jobs.cpp):
>
> where called a func "ExecuteAnddWait" of  "llvm::sys"
>
>     return llvm::sys::ExecuteAndWait(Executable, Argv.data(), /*env*/
> nullptr,
>                                      Redirects, /*secondsToWait*/ 0,
>                                      /*memoryLimit*/ 0, ErrMsg,
>                                      ExecutionFailed);
>
> but the "Executable" is "...path/clang-4.0" - the file, that I launched in
> the debugger o__O
>
> 5) so llvm::sys::ExecuteAndWait(Executable,...) is called and that's all,
> finish, console output with my AST. It didn't jump in the Lexer.cpp,
> Sema.cpp, etc.
>
> What should I do in the debugger, in order to see how Lexer, Sema work?
>
> --
> Best wishes,
> Ivan Kush
>
>
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