[libc] Add hardware implementations of ceil and ceilf for aarch64.

This change also introduces a new source layout for adding machine
specific and generic implementations. To keep the scope of this change
small, this new pattern is only applied for ceil, ceilf and ceill.
Follow up changes will switch all math functions in to the new pattern.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D95850

Author: Siva Chandra

libc/src/math/CMakeLists.txt

@@ -1,3 +1,41 @@
+add_subdirectory(generic)
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_MACHINE})
+  add_subdirectory(${LIBC_TARGET_MACHINE})
+endif()
+
+function(add_math_entrypoint_object name)
+  # We prefer machine specific implementation if available. Hence we check
+  # that first and retrun early if we are able to add an alias target for the
+  # machine specific implementation.
+  get_fq_target_name("${LIBC_TARGET_MACHINE}.${name}" fq_machine_specific_target_name)
+  if(TARGET ${fq_machine_specific_target_name})
+    add_entrypoint_object(
+      ${name}
+      ALIAS
+      DEPENDS
+        .${LIBC_TARGET_MACHINE}.${name}
+    )
+    return()
+  endif()
+
+  get_fq_target_name("generic.${name}" fq_generic_target_name)
+  if(TARGET ${fq_generic_target_name})
+    add_entrypoint_object(
+      ${name}
+      ALIAS
+      DEPENDS
+        .generic.${name}
+    )
+    return()
+  endif()
+
+  message(FATAL_ERROR "No machine specific or generic implementation found for ${name}.")
+endfunction()
+
+add_math_entrypoint_object(ceil)
+add_math_entrypoint_object(ceilf)
+add_math_entrypoint_object(ceill)
+
 add_object_library(
   math_utils
   SRCS
@@ -128,42 +166,6 @@ add_entrypoint_object(
     -O2
 )
 
-add_entrypoint_object(
-  ceil
-  SRCS
-    ceil.cpp
-  HDRS
-    ceil.h
-  DEPENDS
-    libc.utils.FPUtil.fputil
-  COMPILE_OPTIONS
-    -O2
-)
-
-add_entrypoint_object(
-  ceilf
-  SRCS
-    ceilf.cpp
-  HDRS
-    ceilf.h
-  DEPENDS
-    libc.utils.FPUtil.fputil
-  COMPILE_OPTIONS
-    -O2
-)
-
-add_entrypoint_object(
-  ceill
-  SRCS
-    ceill.cpp
-  HDRS
-    ceill.h
-  DEPENDS
-    libc.utils.FPUtil.fputil
-  COMPILE_OPTIONS
-    -O2
-)
-
 add_entrypoint_object(
   floor
   SRCS

libc/src/math/aarch64/CMakeLists.txt

@@ -0,0 +1,19 @@
+add_entrypoint_object(
+  ceil
+  SRCS
+    ceil.cpp
+  HDRS
+    ../ceil.h
+  COMPILE_OPTIONS
+    -O2
+)
+
+add_entrypoint_object(
+  ceilf
+  SRCS
+    ceilf.cpp
+  HDRS
+    ../ceilf.h
+  COMPILE_OPTIONS
+    -O2
+)

libc/src/math/aarch64/ceil.cpp

@@ -0,0 +1,25 @@
+//===-- Implementation of the ceil function for aarch64 -------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/ceil.h"
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(double, ceil, (double x)) {
+  double y;
+  __asm__ __volatile__("ldr d0, %1\n"
+                       "frintp d0, d0\n"
+                       "str d0, %0\n"
+                       : "=m"(y)
+                       : "m"(x)
+                       : "d0");
+  return y;
+}
+
+} // namespace __llvm_libc

libc/src/math/aarch64/ceilf.cpp

@@ -0,0 +1,25 @@
+//===-- Implementation of the ceilf function for aarch64 ------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/ceilf.h"
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(float, ceilf, (float x)) {
+  float y;
+  __asm__ __volatile__("ldr s0, %1\n"
+                       "frintp s0, s0\n"
+                       "str s0, %0\n"
+                       : "=m"(y)
+                       : "m"(x)
+                       : "s0");
+  return y;
+}
+
+} // namespace __llvm_libc

libc/src/math/generic/CMakeLists.txt

@@ -0,0 +1,35 @@
+add_entrypoint_object(
+  ceil
+  SRCS
+    ceil.cpp
+  HDRS
+    ../ceil.h
+  DEPENDS
+    libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
+)
+
+add_entrypoint_object(
+  ceilf
+  SRCS
+    ceilf.cpp
+  HDRS
+    ../ceilf.h
+  DEPENDS
+    libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
+)
+
+add_entrypoint_object(
+  ceill
+  SRCS
+    ceill.cpp
+  HDRS
+    ../ceill.h
+  DEPENDS
+    libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
+)

libc/src/math/ceil.cpp renamed to libc/src/math/generic/ceil.cpp

@@ -1070,3 +1070,5 @@ add_fp_unittest(
     libc.src.math.fmaf
     libc.utils.FPUtil.fputil
 )
+
+add_subdirectory(generic)

libc/src/math/ceilf.cpp renamed to libc/src/math/generic/ceilf.cpp

@@ -0,0 +1,39 @@
+add_fp_unittest(
+  ceil_test
+  NEED_MPFR
+  SUITE
+    libc_math_unittests
+  SRCS
+    ../ceil_test.cpp
+  DEPENDS
+    libc.include.math
+    libc.src.math.generic.ceil
+    libc.utils.FPUtil.fputil
+)
+
+add_fp_unittest(
+  ceilf_test
+  NEED_MPFR
+  SUITE
+    libc_math_unittests
+  SRCS
+    ../ceilf_test.cpp
+  DEPENDS
+    libc.include.math
+    libc.src.math.generic.ceilf
+    libc.utils.FPUtil.fputil
+)
+
+add_fp_unittest(
+  ceill_test
+  NEED_MPFR
+  SUITE
+    libc_math_unittests
+  SRCS
+    ../ceill_test.cpp
+  DEPENDS
+    libc.include.math
+    libc.src.math.generic.ceill
+    libc.utils.FPUtil.fputil
+)
+