[libc-commits] [libc] 6066530 - [libc] build with -Werror (#73966)

[via libc-commits]

Author: Nick Desaulniers
Date: 2023-12-04T11:08:59-08:00
New Revision: 606653091d1a66d1a83a1bfdea2883cc8d46687e

URL: https://github.com/llvm/llvm-project/commit/606653091d1a66d1a83a1bfdea2883cc8d46687e
DIFF: https://github.com/llvm/llvm-project/commit/606653091d1a66d1a83a1bfdea2883cc8d46687e.diff

LOG: [libc] build with -Werror (#73966)

A recent commit introduced warnings observable when building unit tests.
If the
unit tests don't fail when warnings are introduced into the build, then
we
might fail to notice them in the stream of output from check-libc.

Link: https://github.com/llvm/llvm-project/pull/72763/files#r1410932348

Added: 
    

Modified: 
    libc/cmake/modules/LLVMLibCObjectRules.cmake
    libc/docs/dev/code_style.rst

Removed: 
    


################################################################################
diff  --git a/libc/cmake/modules/LLVMLibCObjectRules.cmake b/libc/cmake/modules/LLVMLibCObjectRules.cmake
index 5fbbfd58db2d0..ef654bd7b34ab 100644
--- a/libc/cmake/modules/LLVMLibCObjectRules.cmake
+++ b/libc/cmake/modules/LLVMLibCObjectRules.cmake
@@ -43,6 +43,10 @@ function(_get_common_compile_options output_var flags)
     list(APPEND compile_options "-fno-rtti")
     list(APPEND compile_options "-Wall")
     list(APPEND compile_options "-Wextra")
+    # -DLIBC_WNO_ERROR=ON if you can't build cleanly with -Werror.
+    if(NOT LIBC_WNO_ERROR)
+      list(APPEND compile_options "-Werror")
+    endif()
     list(APPEND compile_options "-Wconversion")
     list(APPEND compile_options "-Wno-sign-conversion")
     list(APPEND compile_options "-Wimplicit-fallthrough")

diff  --git a/libc/docs/dev/code_style.rst b/libc/docs/dev/code_style.rst
index a050a4c1d3dd7..eeeced0359adb 100644
--- a/libc/docs/dev/code_style.rst
+++ b/libc/docs/dev/code_style.rst
@@ -178,3 +178,11 @@ these functions do not call the constructors and destructors of the
 allocated/deallocated objects. So, use these functions carefully and only
 when it is absolutely clear that constructor and destructor invocation is
 not required.
+
+Warnings in sources
+===================
+
+We expect contributions to be free of warnings from the `minimum supported
+compiler versions`__ (and newer).
+
+.. __: https://libc.llvm.org/compiler_support.html#minimum-supported-versions