[libc] Add proxy header for float.h. (#93504)

This is the continuation of
https://github.com/llvm/llvm-project/pull/88674.

Fixes #88433, #90496.

---------

Co-authored-by: aniplcc <aniplccode@gmail.com>

libc/hdr/CMakeLists.txt

@@ -87,4 +87,14 @@ add_proxy_header_library(
     libc.include.llvm-libc-macros.time_macros
 )
 
+add_proxy_header_library(
+  float_macros
+  HDRS
+    float_macros.h
+  DEPENDS
+    libc.include.llvm-libc-macros.float_macros
+  FULL_BUILD_DEPENDS
+    libc.include.float
+)
+
 add_subdirectory(types)

libc/hdr/float_macros.h

@@ -0,0 +1,22 @@
+//===-- Definition of macros from math.h ----------------------------------===//
+//
+// 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_HDR_FLOAT_MACROS_H
+#define LLVM_LIBC_HDR_FLOAT_MACROS_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-macros/float-macros.h"
+
+#else // Overlay mode
+
+#include <float.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_FLOAT_MACROS_H

libc/include/llvm-libc-macros/float-macros.h

@@ -9,21 +9,6 @@
 #ifndef LLVM_LIBC_MACROS_FLOAT_MACROS_H
 #define LLVM_LIBC_MACROS_FLOAT_MACROS_H
 
-// Suppress `#include_next is a language extension` warnings.
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wgnu-include-next"
-#pragma clang diagnostic ignored "-Winclude-next-absolute-path"
-#else // gcc
-#pragma GCC system_header
-#endif //__clang__
-
-#include_next <float.h>
-
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif //__clang__
-
 #ifndef FLT_RADIX
 #define FLT_RADIX __FLT_RADIX__
 #endif // FLT_RADIX
@@ -32,9 +17,13 @@
 #define FLT_EVAL_METHOD __FLT_EVAL_METHOD__
 #endif // FLT_EVAL_METHOD
 
-#ifndef DECIMAL_DIG
-#define DECIMAL_DIG __DECIMAL_DIG__
-#endif // DECIMAL_DIG
+#ifndef FLT_ROUNDS
+#if __has_builtin(__builtin_flt_rounds)
+#define FLT_ROUNDS __builtin_flt_rounds()
+#else
+#define FLT_ROUNDS 1
+#endif
+#endif // FLT_ROUNDS
 
 #ifndef FLT_DECIMAL_DIG
 #define FLT_DECIMAL_DIG __FLT_DECIMAL_DIG__
@@ -48,6 +37,10 @@
 #define LDBL_DECIMAL_DIG __LDBL_DECIMAL_DIG__
 #endif // LDBL_DECIMAL_DIG
 
+#ifndef DECIMAL_DIG
+#define DECIMAL_DIG __DECIMAL_DIG__
+#endif // DECIMAL_DIG
+
 #ifndef FLT_DIG
 #define FLT_DIG __FLT_DIG__
 #endif // FLT_DIG
@@ -97,15 +90,15 @@
 #endif // LDBL_MAX
 
 #ifndef FLT_TRUE_MIN
-#define FLT_TRUE_MIN __FLT_TRUE_MIN__
+#define FLT_TRUE_MIN __FLT_DENORM_MIN__
 #endif // FLT_TRUE_MIN
 
 #ifndef DBL_TRUE_MIN
-#define DBL_TRUE_MIN __DBL_TRUE_MIN__
+#define DBL_TRUE_MIN __DBL_DENORM_MIN__
 #endif // DBL_TRUE_MIN
 
 #ifndef LDBL_TRUE_MIN
-#define LDBL_TRUE_MIN __LDBL_TRUE_MIN__
+#define LDBL_TRUE_MIN __LDBL_DENORM_MIN__
 #endif // LDBL_TRUE_MIN
 
 #ifndef FLT_EPSILON

libc/src/__support/macros/properties/CMakeLists.txt

@@ -33,6 +33,6 @@ add_header_library(
     .compiler
     .cpu_features
     .os
-    libc.include.llvm-libc-macros.float_macros
+    libc.hdr.float_macros
     libc.include.llvm-libc-types.float128
 )

libc/src/__support/macros/properties/types.h

@@ -10,7 +10,7 @@
 #ifndef LLVM_LIBC_SRC___SUPPORT_MACROS_PROPERTIES_TYPES_H
 #define LLVM_LIBC_SRC___SUPPORT_MACROS_PROPERTIES_TYPES_H
 
-#include "include/llvm-libc-macros/float-macros.h" // LDBL_MANT_DIG
+#include "hdr/float_macros.h"                      // LDBL_MANT_DIG
 #include "include/llvm-libc-types/float128.h"      // float128
 #include "src/__support/macros/properties/architectures.h"
 #include "src/__support/macros/properties/compiler.h"

libc/src/math/generic/CMakeLists.txt

@@ -2933,6 +2933,7 @@ add_entrypoint_object(
   HDRS
     ../scalbn.h
   DEPENDS
+    libc.hdr.float_macros
     libc.src.__support.FPUtil.manipulation_functions
   COMPILE_OPTIONS
     -O3
@@ -2945,6 +2946,7 @@ add_entrypoint_object(
   HDRS
     ../scalbnf.h
   DEPENDS
+    libc.hdr.float_macros
     libc.src.__support.FPUtil.manipulation_functions
   COMPILE_OPTIONS
     -O3
@@ -2957,6 +2959,7 @@ add_entrypoint_object(
   HDRS
     ../scalbnl.h
   DEPENDS
+    libc.hdr.float_macros
     libc.src.__support.FPUtil.manipulation_functions
   COMPILE_OPTIONS
     -O3
@@ -2969,6 +2972,7 @@ add_entrypoint_object(
   HDRS
     ../scalbnf128.h
   DEPENDS
+    libc.hdr.float_macros
     libc.src.__support.macros.properties.types
     libc.src.__support.FPUtil.manipulation_functions
   COMPILE_OPTIONS

libc/src/math/generic/scalbn.cpp

@@ -7,19 +7,18 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/scalbn.h"
+#include "hdr/float_macros.h"
 #include "src/__support/FPUtil/ManipulationFunctions.h"
 #include "src/__support/common.h"
 
+#if FLT_RADIX != 2
+#error "FLT_RADIX != 2 is not supported."
+#endif
+
 namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(double, scalbn, (double x, int n)) {
-#if !defined(__FLT_RADIX__)
-#error __FLT_RADIX__ undefined.
-#elif __FLT_RADIX__ != 2
-#error __FLT_RADIX__!=2, unimplemented.
-#else
   return fputil::ldexp(x, n);
-#endif
 }
 
 } // namespace LIBC_NAMESPACE

libc/src/math/generic/scalbnf.cpp

@@ -7,19 +7,18 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/scalbnf.h"
+#include "hdr/float_macros.h"
 #include "src/__support/FPUtil/ManipulationFunctions.h"
 #include "src/__support/common.h"
 
+#if FLT_RADIX != 2
+#error "FLT_RADIX != 2 is not supported."
+#endif
+
 namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(float, scalbnf, (float x, int n)) {
-#if !defined(__FLT_RADIX__)
-#error __FLT_RADIX__ undefined.
-#elif __FLT_RADIX__ != 2
-#error __FLT_RADIX__!=2, unimplemented.
-#else
   return fputil::ldexp(x, n);
-#endif
 }
 
 } // namespace LIBC_NAMESPACE

libc/src/math/generic/scalbnf128.cpp

@@ -7,21 +7,18 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/scalbnf128.h"
+#include "hdr/float_macros.h"
 #include "src/__support/FPUtil/ManipulationFunctions.h"
 #include "src/__support/common.h"
 
+#if FLT_RADIX != 2
+#error "FLT_RADIX != 2 is not supported."
+#endif
+
 namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(float128, scalbnf128, (float128 x, int n)) {
-// TODO: should be switched to use `FLT_RADIX` in hdr/float_macros.h" instead
-// see: https://github.com/llvm/llvm-project/issues/90496
-#if !defined(__FLT_RADIX__)
-#error __FLT_RADIX__ undefined.
-#elif __FLT_RADIX__ != 2
-#error __FLT_RADIX__!=2, unimplemented.
-#else
   return fputil::ldexp(x, n);
-#endif
 }
 
 } // namespace LIBC_NAMESPACE

libc/src/math/generic/scalbnl.cpp

@@ -7,19 +7,18 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/scalbnl.h"
+#include "hdr/float_macros.h"
 #include "src/__support/FPUtil/ManipulationFunctions.h"
 #include "src/__support/common.h"
 
+#if FLT_RADIX != 2
+#error "FLT_RADIX != 2 is not supported."
+#endif
+
 namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(long double, scalbnl, (long double x, int n)) {
-#if !defined(__FLT_RADIX__)
-#error __FLT_RADIX__ undefined.
-#elif __FLT_RADIX__ != 2
-#error __FLT_RADIX__!=2, unimplemented.
-#else
   return fputil::ldexp(x, n);
-#endif
 }
 
 } // namespace LIBC_NAMESPACE

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

@@ -127,6 +127,11 @@ libc_support_library(
     hdrs = ["hdr/time_macros.h"],
 )
 
+libc_support_library(
+    name = "hdr_float_macros",
+    hdrs = ["hdr/float_macros.h"],
+)
+
 ############################ Type Proxy Header Files ###########################
 
 libc_support_library(
@@ -189,7 +194,7 @@ libc_support_library(
         ":__support_macros_properties_compiler",
         ":__support_macros_properties_cpu_features",
         ":__support_macros_properties_os",
-        ":llvm_libc_macros_float_macros",
+        ":hdr_float_macros",
         ":llvm_libc_types_float128",
     ],
 )