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This patch adds clang options `-mroptr` and `-mno-roptr` to specify storage
locations for constant pointers on AIX.
When the `-mroptr` option is in effect, constant pointers, virtual function
tables, and virtual type tables are placed in read-only storage. When the
`-mno-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.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D144190
Files:
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/Frontend/CompilerInvocation.cpp
clang/test/CodeGen/PowerPC/aix-roptr.c
clang/test/Driver/ppc-roptr.c
Index: clang/test/Driver/ppc-roptr.c
===================================================================
--- /dev/null
+++ clang/test/Driver/ppc-roptr.c
@@ -0,0 +1,18 @@
+// RUN: %clang -### -target powerpc-ibm-aix-xcoff -mroptr %s 2>&1 | FileCheck %s
+// RUN: %clang -### -target powerpc-ibm-aix-xcoff -mroptr -mno-roptr %s 2>&1 | \
+// RUN: FileCheck %s --check-prefix=ROPTR
+// RUN: %clang -### -target powerpc64-ibm-aix-xcoff -mroptr %s 2>&1 | FileCheck %s
+// RUN: %clang -### -target powerpc64-ibm-aix-xcoff -mroptr -mno-roptr %s 2>&1 | \
+// RUN: FileCheck %s --check-prefix=ROPTR
+// CHECK: "-mroptr"
+// CHECK: "-bforceimprw"
+// ROPTR-NOT: "-mroptr"
+// ROPTR-NOT: "-bforceimprw"
+
+char c1 = 10;
+char c2 = 20;
+char* const c1_ptr = &c1;
+
+int main() {
+ *(char**)&c1_ptr = &c2;
+}
Index: clang/test/CodeGen/PowerPC/aix-roptr.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/PowerPC/aix-roptr.c
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -triple=powerpc-ibm-aix-xcoff -mroptr -fdata-sections \
+// RUN: -S <%s | FileCheck %s --check-prefix=CHECK32
+// RUN: %clang_cc1 -triple=powerpc64-ibm-aix-xcoff -mroptr -fdata-sections \
+// RUN: -S <%s | FileCheck %s --check-prefix=CHECK64
+// RUN: not %clang_cc1 -triple=powerpc-ibm-aix-xcoff -mroptr \
+// RUN: -S <%s 2>&1 | FileCheck %s --check-prefix=DATA_SECTION_ERR
+// RUN: not %clang_cc1 -triple=powerpc64-ibm-aix-xcoff -mroptr \
+// RUN: -S <%s 2>&1 | FileCheck %s --check-prefix=DATA_SECTION_ERR
+// RUN: not %clang_cc1 -triple=powerpc64le-unknown-linux-gnu -mroptr \
+// RUN: -S <%s 2>&1 | FileCheck %s --check-prefix=TARGET_ERR
+// RUN: not %clang -Xclang -triple=powerpc-ibm-aix-xcoff -mroptr -shared \
+// RUN: -S %s 2>&1 | FileCheck %s --check-prefix=SHARED_ERR
+// RUN: not %clang -Xclang -triple=powerpc64-ibm-aix-xcoff -mroptr -shared \
+// RUN: -S %s 2>&1 | FileCheck %s --check-prefix=SHARED_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: -mroptr is supported only with -fdata-sections
+// TARGET_ERR: error: unsupported option '-mroptr' for target 'powerpc64le-unknown-linux-gnu'
+// SHARED_ERR: error: -mroptr is not suppored with -shared
+
+int main() {
+ *(char**)&c1_ptr = &c2;
+}
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -1560,6 +1560,9 @@
if (Opts.EnableAIXExtendedAltivecABI)
GenerateArg(Args, OPT_mabi_EQ_vec_extabi, SA);
+ if (Opts.ReadOnlyPointers)
+ GenerateArg(Args, OPT_mroptr, SA);
+
if (!Opts.OptRecordPasses.empty())
GenerateArg(Args, OPT_opt_record_passes, Opts.OptRecordPasses, SA);
@@ -1949,6 +1952,17 @@
Opts.EnableAIXExtendedAltivecABI = O.matches(OPT_mabi_EQ_vec_extabi);
}
+ if (Arg *A = Args.getLastArg(OPT_mroptr)) {
+ if (!T.isOSAIX())
+ Diags.Report(diag::err_drv_unsupported_opt_for_target)
+ << A->getSpelling() << T.str();
+
+ if (!Args.hasFlag(OPT_fdata_sections, OPT_fno_data_sections, false))
+ Diags.Report(diag::err_roptr_requires_data_sections);
+
+ Opts.ReadOnlyPointers = 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)
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -5253,6 +5253,17 @@
<< A->getSpelling() << RawTriple.str();
}
+ if (Args.hasFlag(options::OPT_mroptr, options::OPT_mno_roptr, false)) {
+ if (!Triple.isOSAIX())
+ D.Diag(diag::err_drv_unsupported_opt_for_target)
+ << "-mroptr" << RawTriple.str();
+
+ if (Args.hasArg(options::OPT_shared))
+ D.Diag(diag::err_roptr_cannot_build_shared);
+
+ CmdArgs.push_back("-mroptr");
+ }
+
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
Index: clang/lib/Driver/ToolChains/AIX.cpp
===================================================================
--- clang/lib/Driver/ToolChains/AIX.cpp
+++ clang/lib/Driver/ToolChains/AIX.cpp
@@ -122,6 +122,14 @@
CmdArgs.push_back("-bnoentry");
}
+ // `-mroptr` implies the `-bforceimprw` linker option.
+ // The `-mroptr` option places constants in RO sections as much as possible.
+ // Then `-bforceimprw` changes such sections to RW if they contain import
+ // symbols that needs to be resolved.
+ if (Args.hasFlag(options::OPT_mroptr, options::OPT_mno_roptr, false)) {
+ 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.
Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -438,6 +438,7 @@
Options.ObjectFilenameForDebug = CodeGenOpts.ObjectFilenameForDebug;
Options.Hotpatch = CodeGenOpts.HotPatch;
Options.JMCInstrument = CodeGenOpts.JMCInstrument;
+ Options.ReadOnlyPointers = CodeGenOpts.ReadOnlyPointers;
switch (CodeGenOpts.getSwiftAsyncFramePointer()) {
case CodeGenOptions::SwiftAsyncFramePointerKind::Auto:
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -3891,6 +3891,9 @@
def msvr4_struct_return : Flag<["-"], "msvr4-struct-return">,
Group<m_Group>, Flags<[CC1Option]>,
HelpText<"Return small structs in registers (PPC32 only)">;
+def mroptr : Flag<["-"], "mroptr">, Group<m_Group>, Flags<[CC1Option]>,
+ HelpText<"Place constant objects with relocatable address values in the RO data section">;
+def mno_roptr : Flag<["-"], "mno-roptr">, Group<m_Group>;
def mvx : Flag<["-"], "mvx">, Group<m_Group>;
def mno_vx : Flag<["-"], "mno-vx">, Group<m_Group>;
Index: clang/include/clang/Basic/DiagnosticDriverKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticDriverKinds.td
+++ clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -649,6 +649,8 @@
"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<"-mroptr is supported only with -fdata-sections">;
+def err_roptr_cannot_build_shared: Error<"-mroptr is not suppored 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'">;
Index: clang/include/clang/Basic/CodeGenOptions.def
===================================================================
--- clang/include/clang/Basic/CodeGenOptions.def
+++ 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(ReadOnlyPointers, 1, 0) ///< Set for -mroptr.
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.
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -118,6 +118,8 @@
AIX Support
-----------
+- Introduced the ``-mroptr`` option to place constant objects with relocatable
+ address values in the ready-only data section.
C Language Changes in Clang
---------------------------
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