[XCOFF][AIX] Generate LSDA data and compact unwind section on AIX

Summary:
AIX uses the existing EH infrastructure in clang and llvm.
The major differences would be
1. AIX do not have CFI instructions.
2. AIX uses a new personality routine, named __xlcxx_personality_v1.
   It doesn't use the GCC personality rountine, because the
   interoperability is not there yet on AIX.
3. AIX do not use eh_frame sections. Instead, it would use a eh_info
section (compat unwind section) to store the information about
personality routine and LSDA data address.

Reviewed By: daltenty, hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D91455

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index fbc7cf1..a67e4b33 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -883,6 +883,14 @@ void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
   // The TOC-base always has 0 size, but 4 byte alignment.
   TOCBaseSection->setAlignment(Align(4));
 
+  LSDASection = Ctx->getXCOFFSection(".gcc_except_table",
+                                     XCOFF::StorageMappingClass::XMC_RO,
+                                     XCOFF::XTY_SD, SectionKind::getReadOnly());
+
+  CompactUnwindSection =
+      Ctx->getXCOFFSection(".eh_info_table", XCOFF::StorageMappingClass::XMC_RW,
+                           XCOFF::XTY_SD, SectionKind::getData());
+
   // DWARF sections for XCOFF are not csects. They are special STYP_DWARF
   // sections, and the individual DWARF sections are distinguished by their
   // section subtype.