Add function-specific shared header and add support bazel targets.

Author: lntue

libc/shared/math.h

@@ -10,14 +10,7 @@
 #define LLVM_LIBC_SHARED_MATH_H
 
 #include "libc_common.h"
-#include "src/__support/math/expf.h"
 
-namespace LIBC_NAMESPACE_DECL {
-namespace shared {
+#include "math/expf.h"
 
-using math::expf;
-
-} // namespace shared
-} // namespace LIBC_NAMESPACE_DECL
-
-#endif // LLVM_LIBC_SHARED_FP_BITS_H
+#endif // LLVM_LIBC_SHARED_MATH_H

libc/shared/math/expf.h

@@ -0,0 +1,23 @@
+//===-- Shared expf function ------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SHARED_MATH_EXPF_H
+#define LLVM_LIBC_SHARED_MATH_EXPF_H
+
+#include "shared/libc_common.h"
+#include "src/__support/math/expf.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::expf;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_EXPF_H

utils/bazel/llvm-project-overlay/libc/BUILD.bazel

@@ -1616,13 +1616,18 @@ libc_header_library(
 
 ############################### errno ########################################
 
+libc_support_library(
+    name = "__support_libc_errno",
+    hdrs = ["src/__support/libc_errno.h"],
+)
+
 libc_support_library(
     name = "errno",
     srcs = ["src/errno/libc_errno.cpp"],
-    hdrs = ["src/__support/libc_errno.h"],
     deps = [
         ":__support_common",
         ":__support_cpp_atomic",
+        ":__support_libc_errno",
         ":__support_macros_attributes",
         ":__support_macros_properties_architectures",
         ":hdr_errno_macros",
@@ -1973,6 +1978,29 @@ libc_support_library(
     ],
 )
 
+libc_support_library(
+    name = "__support_math_exp_float_constants",
+    hdrs = ["src/__support/math/exp_float_constants.h"],
+)
+
+libc_support_library(
+    name = "__support_math_expf",
+    hdrs = ["src/__support/math/expf.h"],
+    deps = [
+        ":__support_common",
+        ":__support_fputil_fenv_impl",
+        ":__support_fputil_fp_bits",
+        ":__support_fputil_multiply_add",
+        ":__support_fputil_nearest_integer",
+        ":__support_fputil_polyeval",
+        ":__support_fputil_rounding_mode",
+        ":__support_libc_errno",
+        ":__support_macros_config",
+        ":__support_macros_optimization",
+        ":__support_math_exp_float_constants",
+    ],
+)
+
 ############################### complex targets ################################
 
 libc_function(
@@ -2569,18 +2597,9 @@ libc_math_function(
 
 libc_math_function(
     name = "expf",
-    hdrs = [
-        "src/__support/exp_float_constants.h",
-        "src/__support/expf.h",
-    ],
     additional_deps = [
-        ":__support_fputil_fma",
-        ":__support_fputil_multiply_add",
-        ":__support_fputil_nearest_integer",
-        ":__support_fputil_polyeval",
-        ":__support_fputil_rounding_mode",
-        ":__support_macros_optimization",
-        ":common_constants",
+        ":__support_math_expf",
+        ":errno",
     ],
 )
 

utils/bazel/llvm-project-overlay/libc/libc_build_rules.bzl

@@ -250,7 +250,6 @@ def libc_header_library(name, hdrs, deps = [], **kwargs):
 
 def libc_math_function(
         name,
-        hdrs = [],
         additional_deps = None):
     """Add a target for a math function.
 
@@ -277,6 +276,6 @@ def libc_math_function(
     libc_function(
         name = name,
         srcs = ["src/math/generic/" + name + ".cpp"],
-        hdrs = ["src/math/" + name + ".h"] + hdrs,
+        hdrs = ["src/math/" + name + ".h"],
         deps = [":__support_common"] + OLD_FPUTIL_DEPS + additional_deps,
     )

utils/bazel/llvm-project-overlay/libc/test/libc_test_rules.bzl

@@ -31,6 +31,7 @@ def libc_test(name, copts = [], deps = [], local_defines = [], **kwargs):
         deps = [
             "//libc/test/UnitTest:LibcUnitTest",
             "//libc:__support_macros_config",
+            "//libc:__support_libc_errno",
             "//libc:errno",
             "//libc:func_aligned_alloc",
             "//libc:func_free",