diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -343,6 +343,12 @@ This option is an alternative to the `--build-id=0xHEXSTRING` GNU linker option which is currently not supported by the AIX linker. +- Introduced the ``-mxcoff-roptr`` option to place constant objects with + relocatable address values in the read-only data section. This option should + be used with the ``-fdata-sections`` option, and is not supported with + ``-fno-data-sections``. When ``-mxcoff-roptr`` is in effect at link time, + read-only data sections with relocatable address values that resolve to + imported symbols are made writable. WebAssembly Support ^^^^^^^^^^^^^^^^^^^ diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def --- a/clang/include/clang/Basic/CodeGenOptions.def +++ b/clang/include/clang/Basic/CodeGenOptions.def @@ -52,6 +52,7 @@ ///< Produce unique section names with ///< basic block sections. CODEGENOPT(EnableAIXExtendedAltivecABI, 1, 0) ///< Set for -mabi=vec-extabi. Enables the extended Altivec ABI on AIX. +CODEGENOPT(XCOFFReadOnlyPointers, 1, 0) ///< Set for -mxcoff-roptr. ENUM_CODEGENOPT(FramePointer, FramePointerKind, 2, FramePointerKind::None) /// frame-pointer: all,non-leaf,none CODEGENOPT(ClearASTBeforeBackend , 1, 0) ///< Free the AST before running backend code generation. Only works with -disable-free. diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td --- a/clang/include/clang/Basic/DiagnosticDriverKinds.td +++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td @@ -643,6 +643,8 @@ "OBJECT_MODE setting %0 is not recognized and is not a valid setting">; def err_aix_unsupported_tls_model : Error<"TLS model '%0' is not yet supported on AIX">; +def err_roptr_requires_data_sections: Error<"-mxcoff-roptr is supported only with -fdata-sections">; +def err_roptr_cannot_build_shared: Error<"-mxcoff-roptr is not supported with -shared">; def err_invalid_cxx_abi : Error<"invalid C++ ABI name '%0'">; def err_unsupported_cxx_abi : Error<"C++ ABI '%0' is not supported on target triple '%1'">; diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -3894,6 +3894,9 @@ def msvr4_struct_return : Flag<["-"], "msvr4-struct-return">, Group, Flags<[CC1Option]>, HelpText<"Return small structs in registers (PPC32 only)">; +def mxcoff_roptr : Flag<["-"], "mxcoff-roptr">, Group, Flags<[CC1Option]>, + HelpText<"Place constant objects with relocatable address values in the RO data section and add -bforceimprw to the linker flags (AIX only)">; +def mno_xcoff_roptr : Flag<["-"], "mno-xcoff-roptr">, Group; def mvx : Flag<["-"], "mvx">, Group; def mno_vx : Flag<["-"], "mno-vx">, Group; diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp --- a/clang/lib/CodeGen/BackendUtil.cpp +++ b/clang/lib/CodeGen/BackendUtil.cpp @@ -436,6 +436,7 @@ Options.ObjectFilenameForDebug = CodeGenOpts.ObjectFilenameForDebug; Options.Hotpatch = CodeGenOpts.HotPatch; Options.JMCInstrument = CodeGenOpts.JMCInstrument; + Options.XCOFFReadOnlyPointers = CodeGenOpts.XCOFFReadOnlyPointers; switch (CodeGenOpts.getSwiftAsyncFramePointer()) { case CodeGenOptions::SwiftAsyncFramePointerKind::Auto: diff --git a/clang/lib/Driver/ToolChains/AIX.cpp b/clang/lib/Driver/ToolChains/AIX.cpp --- a/clang/lib/Driver/ToolChains/AIX.cpp +++ b/clang/lib/Driver/ToolChains/AIX.cpp @@ -122,6 +122,17 @@ CmdArgs.push_back("-bnoentry"); } + if (Args.hasFlag(options::OPT_mxcoff_roptr, options::OPT_mno_xcoff_roptr, + false)) { + if (Args.hasArg(options::OPT_shared)) + D.Diag(diag::err_roptr_cannot_build_shared); + + // The `-mxcoff-roptr` option places constants in RO sections as much as + // possible. Then `-bforceimprw` changes such sections to RW if they contain + // imported symbols that needs to be resolved. + CmdArgs.push_back("-bforceimprw"); + } + // PGO instrumentation generates symbols belonging to special sections, and // the linker needs to place all symbols in a particular section together in // memory; the AIX linker does that under an option. diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -5245,6 +5245,19 @@ << A->getSpelling() << RawTriple.str(); } + if (Args.hasArg(options::OPT_mxcoff_roptr) || + Args.hasArg(options::OPT_mno_xcoff_roptr)) { + bool HasRoptr = Args.hasFlag(options::OPT_mxcoff_roptr, + options::OPT_mno_xcoff_roptr, false); + StringRef OptStr = HasRoptr ? "-mxcoff-roptr" : "-mno-xcoff-roptr"; + if (!Triple.isOSAIX()) + D.Diag(diag::err_drv_unsupported_opt_for_target) + << OptStr << RawTriple.str(); + + if (HasRoptr) + CmdArgs.push_back("-mxcoff-roptr"); + } + if (Arg *A = Args.getLastArg(options::OPT_Wframe_larger_than_EQ)) { StringRef v = A->getValue(); // FIXME: Validate the argument here so we don't produce meaningless errors diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp --- a/clang/lib/Driver/ToolChains/CommonArgs.cpp +++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp @@ -704,6 +704,28 @@ CmdArgs.push_back( Args.MakeArgString(Twine(PluginOptPrefix) + "-data-sections=0")); + if (Args.hasArg(options::OPT_mxcoff_roptr) || + Args.hasArg(options::OPT_mno_xcoff_roptr)) { + bool HasRoptr = Args.hasFlag(options::OPT_mxcoff_roptr, + options::OPT_mno_xcoff_roptr, false); + StringRef OptStr = HasRoptr ? "-mxcoff-roptr" : "-mno-xcoff-roptr"; + + if (!IsOSAIX) + D.Diag(diag::err_drv_unsupported_opt_for_target) + << OptStr << ToolChain.getTriple().str(); + + if (HasRoptr) { + // On AIX, data_sections is on by default. We only need to check + // if data_sections is explicitly turned off. + if (!Args.hasFlag(options::OPT_fdata_sections, + options::OPT_fno_data_sections, UseSeparateSections)) + D.Diag(diag::err_roptr_requires_data_sections); + + CmdArgs.push_back( + Args.MakeArgString(Twine(PluginOptPrefix) + "-mxcoff-roptr")); + } + } + // Pass an option to enable split machine functions. if (auto *A = Args.getLastArg(options::OPT_fsplit_machine_functions, options::OPT_fno_split_machine_functions)) { diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -1560,6 +1560,9 @@ if (Opts.EnableAIXExtendedAltivecABI) GenerateArg(Args, OPT_mabi_EQ_vec_extabi, SA); + if (Opts.XCOFFReadOnlyPointers) + GenerateArg(Args, OPT_mxcoff_roptr, SA); + if (!Opts.OptRecordPasses.empty()) GenerateArg(Args, OPT_opt_record_passes, Opts.OptRecordPasses, SA); @@ -1949,6 +1952,25 @@ Opts.EnableAIXExtendedAltivecABI = O.matches(OPT_mabi_EQ_vec_extabi); } + if (Arg *A = Args.getLastArg(OPT_mxcoff_roptr)) { + if (!T.isOSAIX()) + Diags.Report(diag::err_drv_unsupported_opt_for_target) + << A->getSpelling() << T.str(); + + // Since the storage mapping class is specified per csect, + // without using data sections, it is less effective to use read-only + // pointers. Using read-only pointers may cause other RO variables in the + // same csect to become RW when the linker acts upon `-bforceimprw`; + // therefore, we require that separate data sections + // are used when `-mxcoff-roptr` is in effect. We respect the setting of + // data-sections since we have not found reasons to do otherwise that + // overcome the user surprise of not respecting the setting. + if (!Args.hasFlag(OPT_fdata_sections, OPT_fno_data_sections, false)) + Diags.Report(diag::err_roptr_requires_data_sections); + + Opts.XCOFFReadOnlyPointers = true; + } + if (Arg *A = Args.getLastArg(OPT_mabi_EQ_quadword_atomics)) { if (!T.isOSAIX() || T.isPPC32()) Diags.Report(diag::err_drv_unsupported_opt_for_target) diff --git a/clang/test/CodeGen/PowerPC/aix-roptr.c b/clang/test/CodeGen/PowerPC/aix-roptr.c new file mode 100644 --- /dev/null +++ b/clang/test/CodeGen/PowerPC/aix-roptr.c @@ -0,0 +1,30 @@ +// RUN: %clang_cc1 -triple=powerpc-ibm-aix-xcoff -mxcoff-roptr -fdata-sections \ +// RUN: -S <%s | FileCheck %s --check-prefix=CHECK32 +// RUN: %clang_cc1 -triple=powerpc64-ibm-aix-xcoff -mxcoff-roptr -fdata-sections \ +// RUN: -S <%s | FileCheck %s --check-prefix=CHECK64 +// RUN: not %clang_cc1 -triple=powerpc-ibm-aix-xcoff -mxcoff-roptr \ +// RUN: -S <%s 2>&1 | FileCheck %s --check-prefix=DATA_SECTION_ERR +// RUN: not %clang_cc1 -triple=powerpc64-ibm-aix-xcoff -mxcoff-roptr \ +// RUN: -S <%s 2>&1 | FileCheck %s --check-prefix=DATA_SECTION_ERR +// RUN: not %clang_cc1 -triple=powerpc64le-unknown-linux-gnu -mxcoff-roptr \ +// RUN: %s 2>&1 | FileCheck %s --check-prefix=TARGET_ROPTR_ERR + +char c1 = 10; +char c2 = 20; +char* const c1_ptr = &c1; +// CHECK32: .csect c1_ptr[RO],2 +// CHECK32-NEXT: .globl c1_ptr[RO] +// CHECK32-NEXT: .align 2 +// CHECK32-NEXT: .vbyte 4, c1[RW] + +// CHECK64: .csect c1_ptr[RO],3 +// CHECK64-NEXT: .globl c1_ptr[RO] +// CHECK64-NEXT: .align 3 +// CHECK64-NEXT: .vbyte 8, c1[RW] + +// DATA_SECTION_ERR: error: -mxcoff-roptr is supported only with -fdata-sections +// TARGET_ROPTR_ERR: error: unsupported option '-mxcoff-roptr' for target 'powerpc64le-unknown-linux-gnu' + +int main() { + *(char**)&c1_ptr = &c2; +} diff --git a/clang/test/Driver/ppc-roptr.c b/clang/test/Driver/ppc-roptr.c new file mode 100644 --- /dev/null +++ b/clang/test/Driver/ppc-roptr.c @@ -0,0 +1,46 @@ +// RUN: %clang -### --target=powerpc-ibm-aix-xcoff -mxcoff-roptr %s 2>&1 | \ +// RUN: FileCheck %s --check-prefixes=ROPTR,LINK +// RUN: %clang -### --target=powerpc-ibm-aix-xcoff -c -mxcoff-roptr %s 2>&1 | \ +// RUN: FileCheck %s --check-prefix=ROPTR +// RUN: %clang -### --target=powerpc-ibm-aix-xcoff -mxcoff-roptr -mno-xcoff-roptr %s 2>&1 | \ +// RUN: FileCheck %s --check-prefix=NO_ROPTR + +// RUN: %clang -### --target=powerpc64-ibm-aix-xcoff -mxcoff-roptr %s 2>&1 | \ +// RUN: FileCheck %s --check-prefixes=ROPTR,LINK +// RUN: %clang -### --target=powerpc64-ibm-aix-xcoff -S -mxcoff-roptr %s 2>&1 | \ +// RUN: FileCheck %s --check-prefix=ROPTR +// RUN: %clang -### --target=powerpc-ibm-aix-xcoff %s 2>&1 | \ +// RUN: FileCheck %s --check-prefix=NO_ROPTR +// RUN: %clang -### --target=powerpc64-ibm-aix-xcoff -mxcoff-roptr -flto %s 2>&1 | \ +// RUN: FileCheck %s --check-prefixes=ROPTR,LINK,LTO_ROPTR +// RUN: touch %t.o +// RUN: %clang -### --target=powerpc64-ibm-aix-xcoff -mxcoff-roptr %t.o 2>&1 | \ +// RUN: FileCheck %s --check-prefix=LINK + +// RUN: %clang -### --target=powerpc64le-unknown-linux-gnu -mxcoff-roptr \ +// RUN: %s 2>&1 | FileCheck %s --check-prefix=TARGET_ROPTR_ERR +// RUN: %clang -### --target=powerpc64le-unknown-linux-gnu -mno-xcoff-roptr \ +// RUN: %s 2>&1 | FileCheck %s --check-prefix=TARGET_NOROPTR_ERR +// RUN: touch %t.o +// RUN: %clang -### --target=powerpc64-ibm-aix-xcoff -mxcoff-roptr -shared \ +// RUN: %t.o 2>&1 | FileCheck %s --check-prefix=SHARED_ERR +// RUN: %clang -### --target=powerpc64le-unknown-linux-gnu -mxcoff-roptr -flto \ +// RUN: %t.o 2>&1 | FileCheck %s --check-prefix=TARGET_ROPTR_ERR +// RUN: %clang -### --target=powerpc64-ibm-aix-xcoff -mxcoff-roptr -flto -fno-data-sections \ +// RUN: %t.o 2>&1 | FileCheck %s --check-prefix=DATA_SECTION_ERR +// RUN: %clang -### --target=powerpc64-ibm-aix-xcoff -mno-xcoff-roptr -flto -fno-data-sections \ +// RUN: %t.o 2>&1 | FileCheck %s --check-prefix=NO_DATA_SECTION_ERR +// RUN: %clang -### --target=powerpc64le-unknown-linux-gnu -mno-xcoff-roptr -flto \ +// RUN: %t.o 2>&1 | FileCheck %s --check-prefix=TARGET_NOROPTR_ERR + +// ROPTR: "-mxcoff-roptr" +// LINK: "-bforceimprw" +// LTO_ROPTR: "-bplugin_opt:-mxcoff-roptr" +// NO_ROPTR-NOT: "-mxcoff-roptr" +// NO_ROPTR-NOT: "-bforceimprw" + +// DATA_SECTION_ERR: error: -mxcoff-roptr is supported only with -fdata-sections +// NO_DATA_SECTION_ERR-NOT: error: -mxcoff-roptr is supported only with -fdata-sections +// TARGET_ROPTR_ERR: error: unsupported option '-mxcoff-roptr' for target 'powerpc64le-unknown-linux-gnu' +// TARGET_NOROPTR_ERR: error: unsupported option '-mno-xcoff-roptr' for target 'powerpc64le-unknown-linux-gnu' +// SHARED_ERR: error: -mxcoff-roptr is not supported with -shared