From: David Tenty Date: Mon, 2 May 2022 21:06:04 +0000 (-0400) Subject: [clang][AIX] Don't ignore XCOFF visibility by default X-Git-Tag: upstream/15.0.7~8014 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d9c1d3cbcb9751a6a82cc5e4ada0533cbbc79a1a;p=platform%2Fupstream%2Fllvm.git [clang][AIX] Don't ignore XCOFF visibility by default D87451 added -mignore-xcoff-visibility for AIX targets and made it the default (which mimicked the behaviour of the XL 16.1 compiler on AIX). However, ignoring hidden visibility has unwanted side effects and some libraries depend on visibility to hide non-ABI facing entities from user headers and reserve the right to change these implementation details based on this (https://libcxx.llvm.org/DesignDocs/VisibilityMacros.html). This forces us to use internal linkage fallbacks for these cases on AIX and creates an unwanted divergence in implementations on the plaform. For these reasons, it's preferable to not add -mignore-xcoff-visibility by default, which is what this patch does. Reviewed By: DiggerLin Differential Revision: https://reviews.llvm.org/D125141 --- diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 5a3b206..6d2a1b8 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -298,6 +298,17 @@ Windows Support JustMyCode feature. Note, you may need to manually add ``/JMC`` as additional compile options in the Visual Studio since it currently assumes clang-cl does not support ``/JMC``. +AIX Support +----------- + +- The driver no longer adds ``-mignore-xcoff-visibility`` by default for AIX + targets when no other visibility command-line options are in effect, as + ignoring hidden visibility can silently have undesirable side effects (e.g + when libraries depend on visibility to hide non-ABI facing entities). The + ``-mignore-xcoff-visibility`` option can be manually specified on the + command-line to recover the previous behavior if desired. + + C Language Changes in Clang --------------------------- diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index a9dd4ca..05988cb 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -5922,9 +5922,7 @@ def stack_protector_buffer_size : Separate<["-"], "stack-protector-buffer-size"> MarshallingInfoInt, "8">; def fvisibility : Separate<["-"], "fvisibility">, HelpText<"Default type and symbol visibility">, - MarshallingInfoVisibility, "DefaultVisibility">, - // Always emitting because of the relation to `-mignore-xcoff-visibility`. - AlwaysEmit; + MarshallingInfoVisibility, "DefaultVisibility">; def ftype_visibility : Separate<["-"], "ftype-visibility">, HelpText<"Default type visibility">, MarshallingInfoVisibility, fvisibility.KeyPath>; diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index 847766a..2e205f34 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -3739,28 +3739,7 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args, Opts.GNUCVersion = Major * 100 * 100 + Minor * 100 + Patch; } - // In AIX OS, the -mignore-xcoff-visibility is enable by default if there is - // no -fvisibility=* option. - // This is the reason why '-fvisibility' needs to be always generated: - // its absence implies '-mignore-xcoff-visibility'. - // - // Suppose the original cc1 command line does contain '-fvisibility default': - // '-mignore-xcoff-visibility' should not be implied. - // * If '-fvisibility' is not generated (as most options with default values - // don't), its absence would imply '-mignore-xcoff-visibility'. This changes - // the command line semantics. - // * If '-fvisibility' is generated regardless of its presence and value, - // '-mignore-xcoff-visibility' won't be implied and the command line - // semantics are kept intact. - // - // When the original cc1 command line does **not** contain '-fvisibility', - // '-mignore-xcoff-visibility' is implied. The generated command line will - // contain both '-fvisibility default' and '-mignore-xcoff-visibility' and - // subsequent calls to `CreateFromArgs`/`generateCC1CommandLine` will always - // produce the same arguments. - - if (T.isOSAIX() && (Args.hasArg(OPT_mignore_xcoff_visibility) || - !Args.hasArg(OPT_fvisibility))) + if (T.isOSAIX() && (Args.hasArg(OPT_mignore_xcoff_visibility))) Opts.IgnoreXCOFFVisibility = 1; if (Args.hasArg(OPT_ftrapv)) { diff --git a/clang/test/CodeGen/PowerPC/aix-ignore-xcoff-visibility.cpp b/clang/test/CodeGen/PowerPC/aix-ignore-xcoff-visibility.cpp index 0dc383b..c5b7c77 100644 --- a/clang/test/CodeGen/PowerPC/aix-ignore-xcoff-visibility.cpp +++ b/clang/test/CodeGen/PowerPC/aix-ignore-xcoff-visibility.cpp @@ -1,8 +1,8 @@ // RUN: %clang_cc1 -no-opaque-pointers -triple powerpc-unknown-aix -emit-llvm -o - -x c++ %s | \ -// RUN: FileCheck -check-prefix=NOVISIBILITY-IR %s +// RUN: FileCheck -check-prefix=VISIBILITY-IR %s // RUN: %clang_cc1 -no-opaque-pointers -triple powerpc-unknown-aix -emit-llvm -round-trip-args -o - -x c++ %s | \ -// RUN: FileCheck -check-prefix=NOVISIBILITY-IR %s +// RUN: FileCheck -check-prefix=VISIBILITY-IR %s // RUN: %clang_cc1 -no-opaque-pointers -triple powerpc-unknown-aix -mignore-xcoff-visibility -fvisibility default -emit-llvm -o - -x c++ %s | \ // RUN: FileCheck -check-prefix=NOVISIBILITY-IR %s diff --git a/clang/test/CodeGen/PowerPC/aix-visibility-inlines-hidden.cpp b/clang/test/CodeGen/PowerPC/aix-visibility-inlines-hidden.cpp index aadca29..27d1c11 100644 --- a/clang/test/CodeGen/PowerPC/aix-visibility-inlines-hidden.cpp +++ b/clang/test/CodeGen/PowerPC/aix-visibility-inlines-hidden.cpp @@ -1,13 +1,13 @@ // RUN: %clang_cc1 -triple powerpc-unknown-aix -mcmodel=large -emit-llvm -o - -x c++ %s | \ -// RUN: FileCheck -check-prefix=NOVISIBILITY-IR %s +// RUN: FileCheck -check-prefix=VISIBILITY-IR %s // RUN: %clang_cc1 -triple powerpc-unknown-aix -mcmodel=large \ // RUN: -fvisibility-inlines-hidden -emit-llvm -o - -x c++ %s | \ -// RUN: FileCheck -check-prefix=NOVISIBILITY-IR %s +// RUN: FileCheck -check-prefixes=VISIBILITY-IR,HIDDENINLINE-IR %s // RUN: %clang_cc1 -triple powerpc-unknown-aix -mcmodel=large -fvisibility-inlines-hidden \ // RUN: -fvisibility default -emit-llvm -o - -x c++ %s | \ -// RUN: FileCheck -check-prefix=VISIBILITY-IR %s +// RUN: FileCheck -check-prefixes=VISIBILITY-IR,HIDDENINLINE-IR %s // RUN: %clang_cc1 -triple powerpc-unknown-aix -mcmodel=large -mignore-xcoff-visibility -emit-llvm \ // RUN: -fvisibility-inlines-hidden -fvisibility default -o - -x c++ %s | \ @@ -30,7 +30,7 @@ int bar() { return x; } -// VISIBILITY-IR: define linkonce_odr hidden void @_Z1fv() +// HIDDENINLINE-IR: define linkonce_odr hidden void @_Z1fv() // NOVISIBILITY-IR: define linkonce_odr void @_Z1fv() // VISIBILITY-IR: define linkonce_odr hidden void @_Z3foov()