[libc] Add proxy header `hdr/float-macros.h`

[lntue]

Context: #87017

Similar PR: #87598, #87863.

Add a proxy header for float.h so that our implementations and tests will work nicely for both overlay and full build modes.

• Add libc/hdr/float_macros.h that will include the system <float.h> in overlay mode or include libc/include/llvm-libc-macros/float-macros.h in full build mode.
• Add its corresponding cmake targets in libc/hdr/CMakeLists.txt.
• Remove the #include_next <float.h> in libc/include/llvm-libc-macros/float-macros.h and all the diagnostic suppression around it.
• Move the filling-in parts such as

#ifndef FLT_RADIX
#define FLT_RADIX __FLT_RADIX__
#endif // FLT_RADIX

to the proxy header libc/hdr/float_macros.h in the overlay mode, after including the system <float.h>.

• Change macro definitions in the full build header libc/include/llvm-libc-macros/float-macros.h to something like:

#ifdef __FLT_RADIX__
#define FLT_RADIX __FLT_RADIX__
#else
#define FLT_RADIX 2
#endif // FLT_RADIX

• Change all the usage of include/llvm-libc-macros/float-macros.h to hdr/float_macros.h, and update the CMake dependency accordingly.
• Add their corresponding bazel targets in utils/bazel/llvm-project-overlay/libc/BUILD.bazel.
• Update bazel dependencies.
• Test in overlay mode:

from "llvm-project/build":
$ cmake ../llvm -GNinja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS=libc
$ ninja libc
$ ninja check-libc

• Test in full build mode:

from "llvm-project/build":
$ cmake ../llvm -GNinja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS="llvm;clang;compiler-rt;libc" -DLLVM_LIBC_INCLUDE_SCUDO=ON -DLLVM_LIBC_FULL_BUILD=ON
$ ninja libc
$ ninja check-libc

• Test bazel build:

from "llvm-project/utils/bazel/"
$ bazel clean
$ bazel build --config=generic_clang --features=layering_check @llvm-project//libc/...
$ bazel test --config=generic_clang --features=layering_check @llvm-project//libc/...

[llvmbot]

@llvm/issue-subscribers-libc

Author: None (lntue)

Context: https://github.com//pull/87017

Similar PR: #87598, #87863.

Add a proxy header for float.h types so that our implementations and tests will work nicely for both overlay and full build modes.

• Add libc/hdr/float_macros.h that will include the system <float.h> in overlay mode or include libc/include/llvm-libc-macros/float-macros.h in full build mode.
• Add its corresponding cmake targets in libc/hdr/CMakeLists.txt.
• Remove the #include_next <float.h> in libc/include/llvm-libc-macros/float-macros.h and all the diagnostic suppression around it.
• Move the filling-in parts such as

#ifndef FLT_RADIX
#define FLT_RADIX __FLT_RADIX__
#endif // FLT_RADIX

to the proxy header libc/hdr/float_macros.h in the overlay mode, after including the system <float.h>.

• Change macro definitions in the full build header libc/include/llvm-libc-macros/float-macros.h to something like:

#ifdef __FLT_RADIX__
#define FLT_RADIX __FLT_RADIX__
#else
#define FLT_RADIX 2
#endif // FLT_RADIX

• Add their corresponding bazel targets in utils/bazel/llvm-project-overlay/libc/BUILD.bazel.
• Update bazel dependencies.
• Test in overlay mode:

from "llvm-project/build":
$ cmake ../llvm -GNinja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS=libc
$ ninja libc
$ ninja check-libc

• Test in full build mode:

from "llvm-project/build":
$ cmake ../llvm -GNinja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS="llvm;clang;compiler-rt;libc" -DLLVM_LIBC_INCLUDE_SCUDO=ON -DLLVM_LIBC_FULL_BUILD=ON
$ ninja libc
$ ninja check-libc

• Test bazel build:

from "llvm-project/utils/bazel/"
$ bazel clean
$ bazel build --config=generic_clang --features=layering_check @<!-- -->llvm-project//libc/...
$ bazel test --config=generic_clang --features=layering_check @<!-- -->llvm-project//libc/...

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. Check that no other contributor has already been assigned to this issue. If you believe that no one is actually working on it despite an assignment, ping the person. After one week without a response, the assignee may be changed.
2. In the comments of this issue, request for it to be assigned to you, or just create a pull request after following the steps below. Mention this issue in the description of the pull request.
3. Fix the issue locally.
4. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
5. Create a Git commit.
6. Run git clang-format HEAD~1 to format your changes.
7. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation. Mention this issue in the description of the pull request.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: None (lntue)

Context: https://github.com//pull/87017

Similar PR: #87598, #87863.

Add a proxy header for float.h types so that our implementations and tests will work nicely for both overlay and full build modes.

• Add libc/hdr/float_macros.h that will include the system <float.h> in overlay mode or include libc/include/llvm-libc-macros/float-macros.h in full build mode.
• Add its corresponding cmake targets in libc/hdr/CMakeLists.txt.
• Remove the #include_next <float.h> in libc/include/llvm-libc-macros/float-macros.h and all the diagnostic suppression around it.
• Move the filling-in parts such as

#ifndef FLT_RADIX
#define FLT_RADIX __FLT_RADIX__
#endif // FLT_RADIX

to the proxy header libc/hdr/float_macros.h in the overlay mode, after including the system <float.h>.

• Change macro definitions in the full build header libc/include/llvm-libc-macros/float-macros.h to something like:

#ifdef __FLT_RADIX__
#define FLT_RADIX __FLT_RADIX__
#else
#define FLT_RADIX 2
#endif // FLT_RADIX

• Add their corresponding bazel targets in utils/bazel/llvm-project-overlay/libc/BUILD.bazel.
• Update bazel dependencies.
• Test in overlay mode:

from "llvm-project/build":
$ cmake ../llvm -GNinja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS=libc
$ ninja libc
$ ninja check-libc

• Test in full build mode:

from "llvm-project/build":
$ cmake ../llvm -GNinja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS="llvm;clang;compiler-rt;libc" -DLLVM_LIBC_INCLUDE_SCUDO=ON -DLLVM_LIBC_FULL_BUILD=ON
$ ninja libc
$ ninja check-libc

• Test bazel build:

from "llvm-project/utils/bazel/"
$ bazel clean
$ bazel build --config=generic_clang --features=layering_check @<!-- -->llvm-project//libc/...
$ bazel test --config=generic_clang --features=layering_check @<!-- -->llvm-project//libc/...

[aniplcc]

I'll work on this.