[AIX][XCOFF] emit symbol visibility for xcoff object file.

SUMMARY:

Reviewers:  Jason liu

Differential Revision: https://reviews.llvm.org/D84265

Author: diggerlin

llvm/include/llvm/MC/MCSectionXCOFF.h

@@ -66,6 +66,11 @@ class MCSectionXCOFF final : public MCSection {
   XCOFF::StorageClass getStorageClass() const {
     return QualName->getStorageClass();
   }
+
+  XCOFF::VisibilityType getVisibilityType() const {
+    return QualName->getVisibilityType();
+  }
+
   XCOFF::SymbolType getCSectType() const { return Type; }
   MCSymbolXCOFF *getQualNameSymbol() const { return QualName; }
 

llvm/lib/MC/XCOFFObjectWriter.cpp

@@ -68,6 +68,11 @@ struct Symbol {
   XCOFF::StorageClass getStorageClass() const {
     return MCSym->getStorageClass();
   }
+
+  XCOFF::VisibilityType getVisibilityType() const {
+    return MCSym->getVisibilityType();
+  }
+
   StringRef getSymbolTableName() const { return MCSym->getSymbolTableName(); }
   Symbol(const MCSymbolXCOFF *MCSym) : MCSym(MCSym), SymbolTableIndex(-1) {}
 };
@@ -561,13 +566,12 @@ void XCOFFObjectWriter::writeSymbolTableEntryForCsectMemberLabel(
   W.write<uint32_t>(CSectionRef.Address + SymbolOffset);
   W.write<int16_t>(SectionIndex);
   // Basic/Derived type. See the description of the n_type field for symbol
-  // table entries for a detailed description. Since we don't yet support
-  // visibility, and all other bits are either optionally set or reserved, this
-  // is always zero.
-  // TODO FIXME How to assert a symbol's visibilty is default?
+  // table entries for a detailed description. Since we support visibility, and
+  // all other bits are either optionally set or reserved, we only set bits 0-3
+  // for symbol's visibility and leave other bits to zero.
   // TODO Set the function indicator (bit 10, 0x0020) for functions
   // when debugging is enabled.
-  W.write<uint16_t>(0);
+  W.write<uint16_t>(SymbolRef.getVisibilityType());
   W.write<uint8_t>(SymbolRef.getStorageClass());
   // Always 1 aux entry for now.
   W.write<uint8_t>(1);
@@ -598,13 +602,12 @@ void XCOFFObjectWriter::writeSymbolTableEntryForControlSection(
   // n_scnum
   W.write<int16_t>(SectionIndex);
   // Basic/Derived type. See the description of the n_type field for symbol
-  // table entries for a detailed description. Since we don't yet support
-  // visibility, and all other bits are either optionally set or reserved, this
-  // is always zero.
-  // TODO FIXME How to assert a symbol's visibilty is default?
+  // table entries for a detailed description. Since we support visibility, and
+  // all other bits are either optionally set or reserved, we only set bits 0-3
+  // for symbol's visibility and leave other bits to zero.
   // TODO Set the function indicator (bit 10, 0x0020) for functions
   // when debugging is enabled.
-  W.write<uint16_t>(0);
+  W.write<uint16_t>(CSectionRef.MCCsect->getVisibilityType());
   // n_sclass
   W.write<uint8_t>(StorageClass);
   // Always 1 aux entry for now.