[clang] 9715af4 - [AIX][clang] Storage Locations for Constant Pointers
Qiongsi Wu via cfe-commits
cfe-commits at lists.llvm.org
Mon May 15 08:34:01 PDT 2023
Author: Qiongsi Wu
Date: 2023-05-15T11:31:00-04:00
New Revision: 9715af434579022b5ef31781be40b722d7e63bee
URL: https://github.com/llvm/llvm-project/commit/9715af434579022b5ef31781be40b722d7e63bee
DIFF: https://github.com/llvm/llvm-project/commit/9715af434579022b5ef31781be40b722d7e63bee.diff
LOG: [AIX][clang] Storage Locations for Constant Pointers
This patch adds clang options `-mxcoff-roptr` and `-mno-xcoff-roptr` to specify storage locations for constant pointers on AIX.
When the `-mxcoff-roptr` option is in effect, constant pointers, virtual function tables, and virtual type tables are placed in read-only storage. When the `-mno-xcoff-roptr` option is in effect, pointers, virtual function tables, and virtual type tables are placed are placed in read/write storage.
This patch depends on https://reviews.llvm.org/D144189.
Reviewed By: hubert.reinterpretcast, stephenpeckham
Differential Revision: https://reviews.llvm.org/D144190
Added:
clang/test/CodeGen/PowerPC/aix-roptr.c
clang/test/Driver/ppc-roptr.c
Modified:
clang/docs/ReleaseNotes.rst
clang/include/clang/Basic/CodeGenOptions.def
clang/include/clang/Basic/DiagnosticDriverKinds.td
clang/include/clang/Driver/Options.td
clang/lib/CodeGen/BackendUtil.cpp
clang/lib/Driver/ToolChains/AIX.cpp
clang/lib/Driver/ToolChains/Clang.cpp
clang/lib/Driver/ToolChains/CommonArgs.cpp
clang/lib/Frontend/CompilerInvocation.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 00edb842ae715..7e8dca8b31871 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -543,6 +543,12 @@ AIX Support
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
index 7151fe9d65682..c026d8e30551f 100644
--- a/clang/include/clang/Basic/CodeGenOptions.def
+++ b/clang/include/clang/Basic/CodeGenOptions.def
@@ -52,6 +52,7 @@ CODEGENOPT(UniqueBasicBlockSectionNames, 1, 1) ///< Set for -funique-basic-block
///< 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
index 27dcc0dd59f37..8a5a3ad3b7fcf 100644
--- a/clang/include/clang/Basic/DiagnosticDriverKinds.td
+++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -649,6 +649,8 @@ def err_drv_invalid_object_mode : Error<
"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
index ac2c3c2fa718b..9d765cc6329b8 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3907,6 +3907,9 @@ def maix_struct_return : Flag<["-"], "maix-struct-return">,
def msvr4_struct_return : Flag<["-"], "msvr4-struct-return">,
Group<m_Group>, Flags<[CC1Option]>,
HelpText<"Return small structs in registers (PPC32 only)">;
+def mxcoff_roptr : Flag<["-"], "mxcoff-roptr">, Group<m_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<m_Group>;
def mvx : Flag<["-"], "mvx">, Group<m_Group>;
def mno_vx : Flag<["-"], "mno-vx">, Group<m_Group>;
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index a0cf26006d16f..4e80c58c09e87 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -435,6 +435,7 @@ static bool initTargetOptions(DiagnosticsEngine &Diags,
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
index 0ac261b548718..46ad8231764db 100644
--- a/clang/lib/Driver/ToolChains/AIX.cpp
+++ b/clang/lib/Driver/ToolChains/AIX.cpp
@@ -122,6 +122,17 @@ void aix::Linker::ConstructJob(Compilation &C, const JobAction &JA,
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 need 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
index 189cbd19e1499..31f2881be6b62 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5241,6 +5241,19 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
<< 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(), V1 = V;
unsigned Size;
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index 7131c26d24a48..4a11be78f37f4 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -749,6 +749,26 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
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) {
+ 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
index cbd2663a56278..c111607b98193 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1560,6 +1560,9 @@ void CompilerInvocation::GenerateCodeGenArgs(
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);
@@ -1933,6 +1936,25 @@ bool CompilerInvocation::ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args,
}
}
+ 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
index 0000000000000..415bfd47bd41f
--- /dev/null
+++ b/clang/test/CodeGen/PowerPC/aix-roptr.c
@@ -0,0 +1,25 @@
+// 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* 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'
diff --git a/clang/test/Driver/ppc-roptr.c b/clang/test/Driver/ppc-roptr.c
new file mode 100644
index 0000000000000..0ab740da9e04a
--- /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
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