diff options
| author | Qiongsi Wu <qwu@ibm.com> | 2023-03-23 09:16:18 -0400 |
|---|---|---|
| committer | Qiongsi Wu <qwu@ibm.com> | 2023-03-23 09:44:47 -0400 |
| commit | 4f9929add5369490c9607fc9203761483d2bc916 (patch) | |
| tree | 1f3e3d4cf0d953c308fa89f93f5d452e82c2fb86 /llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp | |
| parent | fd4aeba307ca30da00a8db21a200cc9afcef63c6 (diff) | |
| download | llvm-4f9929add5369490c9607fc9203761483d2bc916.zip llvm-4f9929add5369490c9607fc9203761483d2bc916.tar.gz llvm-4f9929add5369490c9607fc9203761483d2bc916.tar.bz2 | |
[AIX][CodeGen] Storage Locations for Constant Pointers
This patch adds an `llc` option `-mroptr` to specify storage locations for constant pointers on AIX.
When the `-mroptr` option is specified, constant pointers, virtual function tables, and virtual type tables are placed in read-only storage. Otherwise, by default, pointers, virtual function tables, and virtual type tables are placed are placed in read/write storage.
https://reviews.llvm.org/D144190 enables the `-mroptr` option for `clang`.
Reviewed By: hubert.reinterpretcast, stephenpeckham, myhsu, MaskRay, serge-sans-paille
Differential Revision: https://reviews.llvm.org/D144189
Diffstat (limited to 'llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp index e2fbe02..c81b6bb 100644 --- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp +++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp @@ -2343,8 +2343,11 @@ MCSection *TargetLoweringObjectFileXCOFF::getExplicitSectionGlobal( XCOFF::StorageMappingClass MappingClass; if (Kind.isText()) MappingClass = XCOFF::XMC_PR; - else if (Kind.isData() || Kind.isReadOnlyWithRel() || Kind.isBSS()) + else if (Kind.isData() || Kind.isBSS()) MappingClass = XCOFF::XMC_RW; + else if (Kind.isReadOnlyWithRel()) + MappingClass = + TM.Options.XCOFFReadOnlyPointers ? XCOFF::XMC_RO : XCOFF::XMC_RW; else if (Kind.isReadOnly()) MappingClass = XCOFF::XMC_RO; else @@ -2429,9 +2432,18 @@ MCSection *TargetLoweringObjectFileXCOFF::SelectSectionForGlobal( return TextSection; } - // TODO: We may put Kind.isReadOnlyWithRel() under option control, because - // user may want to have read-only data with relocations placed into a - // read-only section by the compiler. + if (TM.Options.XCOFFReadOnlyPointers && Kind.isReadOnlyWithRel()) { + if (!TM.getDataSections()) + report_fatal_error( + "ReadOnlyPointers is supported only if data sections is turned on"); + + SmallString<128> Name; + getNameWithPrefix(Name, GO, TM); + return getContext().getXCOFFSection( + Name, SectionKind::getReadOnly(), + XCOFF::CsectProperties(XCOFF::XMC_RO, XCOFF::XTY_SD)); + } + // For BSS kind, zero initialized data must be emitted to the .data section // because external linkage control sections that get mapped to the .bss // section will be linked as tentative defintions, which is only appropriate |