[PragmaHandler] Expose `#pragma` location

Currently, a pragma AST node's recorded location starts at the
namespace token (such as `omp` in the case of OpenMP) after the
`#pragma` token, and the `#pragma` location isn't available.  However,
the `#pragma` location can be useful when, for example, rewriting a
directive using Clang's Rewrite facility.

This patch makes `#pragma` locations available in any `PragmaHandler`
but it doesn't yet make use of them.

This patch also uses the new `struct PragmaIntroducer` to simplify
`Preprocessor::HandlePragmaDirective`.  It doesn't do the same for
`PPCallbacks::PragmaDirective` because that changes the API documented
in `clang-tools-extra/docs/pp-trace.rst`, and I'm not sure about
backward compatibility guarantees there.

Reviewed By: ABataev, lebedev.ri, aaron.ballman

Differential Revision: https://reviews.llvm.org/D61643

llvm-svn: 361335
8 files changed
tree: 9addb94c209bdabc550842f7699383ef47b27552
  1. .arcconfig
  2. .clang-format
  3. .clang-tidy
  4. .gitignore
  5. README.md
  6. clang-tools-extra/
  7. clang/
  8. compiler-rt/
  9. debuginfo-tests/
  10. libclc/
  11. libcxx/
  12. libcxxabi/
  13. libunwind/
  14. lld/
  15. lldb/
  16. llgo/
  17. llvm/
  18. openmp/
  19. parallel-libs/
  20. polly/
  21. pstl/
README.md

The LLVM Compiler Infrastructure

This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments.