Summary:
This patch does the following:
1. Make InitTargetOptionsFromCodeGenFlags() accepts Triple as a
parameter, because some options' default value is triple dependant.
2. DataSections is turned on by default on AIX for llc.
3. Test cases change accordingly because of the default behaviour change.
4. Clang Driver passes in -fdata-sections by default on AIX.
Reviewed By: MaskRay, DiggerLin
Differential Revision: https://reviews.llvm.org/D88737
SUMMARY:
In IBM compiler xlclang , there is an option -fnovisibility which suppresses visibility. For more details see: https://www.ibm.com/support/knowledgecenter/SSGH3R_16.1.0/com.ibm.xlcpp161.aix.doc/compiler_ref/opt_visibility.html.
We need to add the option -mignore-xcoff-visibility for compatibility with the IBM AIX OS (as the option is enabled by default in AIX). With this option llvm does not emit any visibility attribute to ASM or XCOFF object file.
The option only work on the AIX OS, for other non-AIX OS using the option will report an unsupported options error.
In AIX OS:
1.1 the option -mignore-xcoff-visibility is enabled by default , if there is not -fvisibility=* and -mignore-xcoff-visibility explicitly in the clang command .
1.2 if there is -fvisibility=* explicitly but not -mignore-xcoff-visibility explicitly in the clang command. it will generate visibility attributes.
1.3 if there are both -fvisibility=* and -mignore-xcoff-visibility explicitly in the clang command. The option "-mignore-xcoff-visibility" wins , it do not emit the visibility attribute.
The option -mignore-xcoff-visibility has no effect on visibility attribute when compile with -emit-llvm option to generated LLVM IR.
Reviewer: daltenty,Jason Liu
Differential Revision: https://reviews.llvm.org/D87451
jasonliu