From 485b9083fe69601c9f3f91f7f1be9d7f3a26bb1e Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne@apple.com>
Date: Thu, 21 May 2020 10:25:15 -0400
Subject: [PATCH] [libc++] Mark __u64toa and __u32toa as noexcept

The two functions don't throw, and the generated code is better when
we explicitly tell the compiler that the functions are noexcept. This
isn't an ABI break because the signatures of the functions stay the
same with or without noexcept.

Fixes https://llvm.org/PR46016

Differential Revision: https://reviews.llvm.org/D80379
---
 libcxx/include/charconv |  4 ++--
 libcxx/src/charconv.cpp | 18 +++++++++---------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/libcxx/include/charconv b/libcxx/include/charconv
index 55809b9..b640002 100644
--- a/libcxx/include/charconv
+++ b/libcxx/include/charconv
@@ -93,8 +93,8 @@ _LIBCPP_PUSH_MACROS
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 namespace __itoa {
-_LIBCPP_AVAILABILITY_TO_CHARS _LIBCPP_FUNC_VIS char* __u64toa(uint64_t __value, char* __buffer);
-_LIBCPP_AVAILABILITY_TO_CHARS _LIBCPP_FUNC_VIS char* __u32toa(uint32_t __value, char* __buffer);
+_LIBCPP_AVAILABILITY_TO_CHARS _LIBCPP_FUNC_VIS char* __u64toa(uint64_t __value, char* __buffer) _NOEXCEPT;
+_LIBCPP_AVAILABILITY_TO_CHARS _LIBCPP_FUNC_VIS char* __u32toa(uint32_t __value, char* __buffer) _NOEXCEPT;
 }
 
 #ifndef _LIBCPP_CXX03_LANG
diff --git a/libcxx/src/charconv.cpp b/libcxx/src/charconv.cpp
index d303588..8cfe40d 100644
--- a/libcxx/src/charconv.cpp
+++ b/libcxx/src/charconv.cpp
@@ -32,7 +32,7 @@ static constexpr char cDigitsLut[200] = {
 
 template <typename T>
 inline _LIBCPP_INLINE_VISIBILITY char*
-append1(char* buffer, T i)
+append1(char* buffer, T i) noexcept
 {
     *buffer = '0' + static_cast<char>(i);
     return buffer + 1;
@@ -40,7 +40,7 @@ append1(char* buffer, T i)
 
 template <typename T>
 inline _LIBCPP_INLINE_VISIBILITY char*
-append2(char* buffer, T i)
+append2(char* buffer, T i) noexcept
 {
     memcpy(buffer, &cDigitsLut[(i)*2], 2);
     return buffer + 2;
@@ -48,21 +48,21 @@ append2(char* buffer, T i)
 
 template <typename T>
 inline _LIBCPP_INLINE_VISIBILITY char*
-append3(char* buffer, T i)
+append3(char* buffer, T i) noexcept
 {
     return append2(append1(buffer, (i) / 100), (i) % 100);
 }
 
 template <typename T>
 inline _LIBCPP_INLINE_VISIBILITY char*
-append4(char* buffer, T i)
+append4(char* buffer, T i) noexcept
 {
     return append2(append2(buffer, (i) / 100), (i) % 100);
 }
 
 template <typename T>
 inline _LIBCPP_INLINE_VISIBILITY char*
-append2_no_zeros(char* buffer, T v)
+append2_no_zeros(char* buffer, T v) noexcept
 {
     if (v < 10)
         return append1(buffer, v);
@@ -72,7 +72,7 @@ append2_no_zeros(char* buffer, T v)
 
 template <typename T>
 inline _LIBCPP_INLINE_VISIBILITY char*
-append4_no_zeros(char* buffer, T v)
+append4_no_zeros(char* buffer, T v) noexcept
 {
     if (v < 100)
         return append2_no_zeros(buffer, v);
@@ -84,7 +84,7 @@ append4_no_zeros(char* buffer, T v)
 
 template <typename T>
 inline _LIBCPP_INLINE_VISIBILITY char*
-append8_no_zeros(char* buffer, T v)
+append8_no_zeros(char* buffer, T v) noexcept
 {
     if (v < 10000)
     {
@@ -99,7 +99,7 @@ append8_no_zeros(char* buffer, T v)
 }
 
 char*
-__u32toa(uint32_t value, char* buffer)
+__u32toa(uint32_t value, char* buffer) _NOEXCEPT
 {
     if (value < 100000000)
     {
@@ -120,7 +120,7 @@ __u32toa(uint32_t value, char* buffer)
 }
 
 char*
-__u64toa(uint64_t value, char* buffer)
+__u64toa(uint64_t value, char* buffer) _NOEXCEPT
 {
     if (value < 100000000)
     {
-- 
2.7.4