1880008 - Add char8_t string overloads to MFBT string functions when compiling with -std=c++20

Status: RESOLVED FIXED

(Core :: MFBT, task, P3)

Description

[Chris Peterson [:cpeterson]]

When compiled with -std=c++17, u8"" string literals have type const char[]. When compiled with -std=c++20, u8"" string literals have type const char8_t[]. This patch adds the minimum char8_t overloads needed to compile Firefox with -std=c++20. If we want to use char8_t in more code or replace Utf8Unit with char8_t, that will require an extensive redesign of MFBT's and xpcom's string classes after we update from -std=c++17 to c++20.

obj-aarch64-unknown-linux-android/dist/include/mozilla/Utf8.h:473:20: error: call to constructor of 'const Utf8Unit' is ambiguous
| const Utf8Unit unit(*(*aIter)++);

mfbt/tests/TestUtf8.cpp:52:25: error: call to 'IsAscii' is ambiguous
| MOZ_RELEASE_ASSERT(!IsAscii(aStart[0]));

xpcom/tests/gtest/TestStrings.cpp:1446:17: error: no matching member function for call to 'Equals'
| EXPECT_TRUE(s.Equals(u8"\uFFFD"));

Comment 1

[Chris Peterson [:cpeterson]]

Attachment: Bug 1880008 - Add char8_t string overloads to MFBT string functions when compiling with -std=c++20. r?#xpcom-reviewers

When compiled with -std=c++17, u8"" string literals have type const char[]. When compiled with -std=c++20, u8"" string literals have type const char8_t[]. This patch adds the minimum char8_t overloads needed to compile Firefox with -std=c++20. If we want to use char8_t in more code or replace Utf8Unit with char8_t, that will require an extensive redesign of MFBT's and xpcom's string classes after we update from -std=c++17 to c++20.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/aaaa3f2b8fed
Add char8_t string overloads to MFBT string functions when compiling with -std=c++20. r=xpcom-reviewers,emilio

Comment 3

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/aaaa3f2b8fed