Commit 91cdbd52 authored by Nick Desaulniers's avatar Nick Desaulniers
Browse files

clang: Switch C compilations to C17 by default. 

Summary:
Matches GCC 8.1 (2018).

Updates documentation+release notes as well.

See also https://reviews.llvm.org/rL220244.

Reviewers: rsmith, aaron.ballman

Reviewed By: rsmith, aaron.ballman

Subscribers: aaron.ballman, dschuff, aheejin, simoncook, s.egerton, cfe-commits, hans, srhines

Tags: #clang

Differential Revision: https://reviews.llvm.org/D75383
parent b9f37e9a

clang/docs/ReleaseNotes.rst

+3 −5
Original line number Diff line number Diff line
@@ -101,12 +101,10 @@ Windows Support 
C Language Changes in Clang

---------------------------



- ...



C11 Feature Support

^^^^^^^^^^^^^^^^^^^

- The default C language standard used when `-std=` is not specified has been

  upgraded from gnu11 to gnu17.



...

- ...



C++ Language Changes in Clang

-----------------------------

clang/docs/UsersManual.rst

+5 −5
Original line number Diff line number Diff line
@@ -80,7 +80,7 @@ Basic Usage 
Intro to how to use a C compiler for newbies.



compile + link compile then link debug info enabling optimizations

picking a language to use, defaults to C11 by default. Autosenses based

picking a language to use, defaults to C17 by default. Autosenses based

on extension. using a makefile



Command Line Options
@@ -2399,10 +2399,10 @@ See :doc:`LanguageExtensions`. 
Differences between various standard modes

------------------------------------------



clang supports the -std option, which changes what language mode clang

uses. The supported modes for C are c89, gnu89, c99, gnu99, c11, gnu11,

c17, gnu17, and various aliases for those modes. If no -std option is

specified, clang defaults to gnu11 mode. Many C99 and C11 features are

clang supports the -std option, which changes what language mode clang uses.

The supported modes for C are c89, gnu89, c99, gnu99, c11, gnu11, c17, gnu17,

c2x, gnu2x, and various aliases for those modes. If no -std option is

specified, clang defaults to gnu17 mode. Many C99 and C11 features are

supported in earlier modes as a conforming extension, with a warning. Use

``-pedantic-errors`` to request an error if a feature from a later standard

revision is used in an earlier mode.

clang/lib/Frontend/CompilerInvocation.cpp

+1 −1
Original line number Diff line number Diff line
@@ -2263,7 +2263,7 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK, 
      if (T.isPS4())

        LangStd = LangStandard::lang_gnu99;

      else

        LangStd = LangStandard::lang_gnu11;

        LangStd = LangStandard::lang_gnu17;

#endif

      break;

    case Language::ObjC:

clang/test/Preprocessor/init-aarch64.c

+2 −2
Original line number Diff line number Diff line
@@ -236,7 +236,7 @@ 
// AARCH64-NEXT: #define __STDC_HOSTED__ 1

// AARCH64-NEXT: #define __STDC_UTF_16__ 1

// AARCH64-NEXT: #define __STDC_UTF_32__ 1

// AARCH64_C: #define __STDC_VERSION__ 201112L

// AARCH64_C: #define __STDC_VERSION__ 201710L

// AARCH64-NEXT: #define __STDC__ 1

// AARCH64-NEXT: #define __UINT16_C_SUFFIX__ 

// AARCH64-NEXT: #define __UINT16_FMTX__ "hX"
@@ -646,7 +646,7 @@ 
// AARCH64-MSVC: #define __STDC_HOSTED__ 0

// AARCH64-MSVC: #define __STDC_UTF_16__ 1

// AARCH64-MSVC: #define __STDC_UTF_32__ 1

// AARCH64-MSVC: #define __STDC_VERSION__ 201112L

// AARCH64-MSVC: #define __STDC_VERSION__ 201710L

// AARCH64-MSVC: #define __STDC__ 1

// AARCH64-MSVC: #define __UINT16_C_SUFFIX__

// AARCH64-MSVC: #define __UINT16_MAX__ 65535

clang/test/Preprocessor/init.c

+9 −9
Original line number Diff line number Diff line
@@ -117,7 +117,7 @@ 
// RUN: %clang_cc1 -E -dM -triple=x86_64-apple-darwin < /dev/null | FileCheck -match-full-lines -check-prefix C-DEFAULT %s

// RUN: %clang_cc1 -E -dM -triple=armv7a-apple-darwin < /dev/null | FileCheck -match-full-lines -check-prefix C-DEFAULT %s

//

// C-DEFAULT:#define __STDC_VERSION__ 201112L

// C-DEFAULT:#define __STDC_VERSION__ 201710L

//

// RUN: %clang_cc1 -ffreestanding -E -dM < /dev/null | FileCheck -match-full-lines -check-prefix FREESTANDING %s

// FREESTANDING:#define __STDC_HOSTED__ 0
@@ -2098,7 +2098,7 @@ 
// MIPS32BE:#define __SIZE_WIDTH__ 32

// MIPS32BE-CXX:#define __STDCPP_DEFAULT_NEW_ALIGNMENT__ 8U

// MIPS32BE:#define __STDC_HOSTED__ 0

// MIPS32BE-C:#define __STDC_VERSION__ 201112L

// MIPS32BE-C:#define __STDC_VERSION__ 201710L

// MIPS32BE:#define __STDC__ 1

// MIPS32BE:#define __UINT16_C_SUFFIX__

// MIPS32BE:#define __UINT16_MAX__ 65535
@@ -2557,7 +2557,7 @@ 
// MIPSN32BE: #define __STDC_HOSTED__ 0

// MIPSN32BE: #define __STDC_UTF_16__ 1

// MIPSN32BE: #define __STDC_UTF_32__ 1

// MIPSN32BE-C: #define __STDC_VERSION__ 201112L

// MIPSN32BE-C: #define __STDC_VERSION__ 201710L

// MIPSN32BE: #define __STDC__ 1

// MIPSN32BE: #define __UINT16_C_SUFFIX__

// MIPSN32BE: #define __UINT16_FMTX__ "hX"
@@ -2864,7 +2864,7 @@ 
// MIPSN32EL: #define __STDC_HOSTED__ 0

// MIPSN32EL: #define __STDC_UTF_16__ 1

// MIPSN32EL: #define __STDC_UTF_32__ 1

// MIPSN32EL: #define __STDC_VERSION__ 201112L

// MIPSN32EL: #define __STDC_VERSION__ 201710L

// MIPSN32EL: #define __STDC__ 1

// MIPSN32EL: #define __UINT16_C_SUFFIX__

// MIPSN32EL: #define __UINT16_FMTX__ "hX"
@@ -5390,7 +5390,7 @@ 
// PPC-DARWIN:#define __SIZE_TYPE__ long unsigned int

// PPC-DARWIN:#define __SIZE_WIDTH__ 32

// PPC-DARWIN:#define __STDC_HOSTED__ 0

// PPC-DARWIN:#define __STDC_VERSION__ 201112L

// PPC-DARWIN:#define __STDC_VERSION__ 201710L

// PPC-DARWIN:#define __STDC__ 1

// PPC-DARWIN:#define __UINT16_C_SUFFIX__

// PPC-DARWIN:#define __UINT16_MAX__ 65535
@@ -6602,7 +6602,7 @@ 
// X86_64-CLOUDABI:#define __STDC_ISO_10646__ 201206L

// X86_64-CLOUDABI:#define __STDC_UTF_16__ 1

// X86_64-CLOUDABI:#define __STDC_UTF_32__ 1

// X86_64-CLOUDABI:#define __STDC_VERSION__ 201112L

// X86_64-CLOUDABI:#define __STDC_VERSION__ 201710L

// X86_64-CLOUDABI:#define __STDC__ 1

// X86_64-CLOUDABI:#define __UINT16_C_SUFFIX__

// X86_64-CLOUDABI:#define __UINT16_FMTX__ "hX"
@@ -7601,7 +7601,7 @@ 
// WEBASSEMBLY-NOT:#define __STDC_NO_THREADS__

// WEBASSEMBLY-NEXT:#define __STDC_UTF_16__ 1

// WEBASSEMBLY-NEXT:#define __STDC_UTF_32__ 1

// WEBASSEMBLY-NEXT:#define __STDC_VERSION__ 201112L

// WEBASSEMBLY-NEXT:#define __STDC_VERSION__ 201710L

// WEBASSEMBLY-NEXT:#define __STDC__ 1

// WEBASSEMBLY-NEXT:#define __UINT16_C_SUFFIX__

// WEBASSEMBLY-NEXT:#define __UINT16_FMTX__ "hX"
@@ -8166,7 +8166,7 @@ 
// RISCV32: #define __STDC_HOSTED__ 0

// RISCV32: #define __STDC_UTF_16__ 1

// RISCV32: #define __STDC_UTF_32__ 1

// RISCV32: #define __STDC_VERSION__ 201112L

// RISCV32: #define __STDC_VERSION__ 201710L

// RISCV32: #define __STDC__ 1

// RISCV32: #define __UINT16_C_SUFFIX__

// RISCV32: #define __UINT16_MAX__ 65535
@@ -8373,7 +8373,7 @@ 
// RISCV64: #define __STDC_HOSTED__ 0

// RISCV64: #define __STDC_UTF_16__ 1

// RISCV64: #define __STDC_UTF_32__ 1

// RISCV64: #define __STDC_VERSION__ 201112L

// RISCV64: #define __STDC_VERSION__ 201710L

// RISCV64: #define __STDC__ 1

// RISCV64: #define __UINT16_C_SUFFIX__

// RISCV64: #define __UINT16_MAX__ 65535