[XCOFF][AIX] Emit TOC entries for object file generation

Summary:
Implement emitTCEntry for PPCTargetXCOFFStreamer.
Add TC csects to TOCCsects for object file writing.

Note:

1. I did not include any raw data testing for this object file generation
because TC entries raw data will all be 0 without relocation implemented.
I will add raw data testing as part of relocation testing later.
2. I removed "Symbol->setFragment(F);" for common symbols because we
 don't need it, and if we have it then we would hit assertions below:
Assertion `(SymbolContents == SymContentsUnset ||
            SymbolContents == SymContentsOffset) &&
            "Cannot get offset for a common/variable symbol"' failed.
3.Fixed incorrect TOC-base alignment.

Differential Revision: https://reviews.llvm.org/D70798

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/MC/XCOFFObjectWriter.cpp b/llvm/lib/MC/XCOFFObjectWriter.cpp
index ab0d9048ecf..773ca3a0909 100644
--- a/llvm/lib/MC/XCOFFObjectWriter.cpp
+++ b/llvm/lib/MC/XCOFFObjectWriter.cpp
@@ -275,6 +275,12 @@ CsectGroup &XCOFFObjectWriter::getCsectGroup(const MCSectionXCOFF *MCSec) {
            "We should have only one TOC-base, and it should be the first csect "
            "in this CsectGroup.");
     return TOCCsects;
+  case XCOFF::XMC_TC:
+    assert(XCOFF::XTY_SD == MCSec->getCSectType() &&
+           "Only an initialized csect can contain TC entry.");
+    assert(!TOCCsects.empty() &&
+           "We should at least have a TOC-base in this CsectGroup.");
+    return TOCCsects;
   default:
     report_fatal_error("Unhandled mapping of csect to section.");
   }