Title: Export unique symbol list with llvm-nm new option "--export-symbols"

Summary:

the patch implement of following functionality.
1. export the symbols from archive or object files.
2. sort the export symbols. (based on same symbol name and visibility)
3. delete the duplicate export symbols (based on same symbol name and visibility)
4. print out the  unique and sorted export symbols (print the symbol name and visibility).

there are two new options are add in the patch
1. --export-symbols (enable the functionality of export unique symbol)
2. --no-rsrc (exclude the symbol name begin with "__rsrc" from be exporting from xcoff object file)

Export symbol list for xcoff object file has the same functionality as
The patch has the same functionality as
https://www.ibm.com/docs/en/xl-c-aix/13.1.0?topic=library-exporting-symbols-createexportlist-utility

Reviewers: James Henderson,Fangrui Song
Differential Revision: https://reviews.llvm.org/D112735

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/Object/XCOFFObjectFile.cpp b/llvm/lib/Object/XCOFFObjectFile.cpp
index f2f6d70..d9ecb0a 100644
--- a/llvm/lib/Object/XCOFFObjectFile.cpp
+++ b/llvm/lib/Object/XCOFFObjectFile.cpp
@@ -615,6 +615,16 @@ Expected<uint32_t> XCOFFObjectFile::getSymbolFlags(DataRefImpl Symb) const {
   if (XCOFFSym.getSectionNumber() == XCOFF::N_UNDEF)
     Result |= SymbolRef::SF_Undefined;
 
+  // There is no visibility in old 32 bit XCOFF object file interpret.
+  if (is64Bit() || (auxiliaryHeader32() && (auxiliaryHeader32()->getVersion() ==
+                                            NEW_XCOFF_INTERPRET))) {
+    uint16_t SymType = XCOFFSym.getSymbolType();
+    if ((SymType & VISIBILITY_MASK) == SYM_V_HIDDEN)
+      Result |= SymbolRef::SF_Hidden;
+
+    if ((SymType & VISIBILITY_MASK) == SYM_V_EXPORTED)
+      Result |= SymbolRef::SF_Exported;
+  }
   return Result;
 }