Add getSymbolAlignment to the ObjectFile interface.

For regular object files this is only meaningful for common symbols. An object
file format with direct support for atoms should be able to provide alignment
information for all symbols.

This replaces getCommonSymbolAlignment and fixes
test-common-symbols-alignment.ll on darwin. This also includes a fix to
MachOObjectFile::getSymbolFlags. It was marking undefined symbols as common
(already tested by existing mcjit tests now that it is used).

llvm-svn: 180736

1 files changed, 19 insertions, 2 deletions

diff --git a/llvm/lib/Object/MachOObjectFile.cpp b/llvm/lib/Object/MachOObjectFile.cpp
index bb6ca93..f6840b8 100644
--- a/llvm/lib/Object/MachOObjectFile.cpp
+++ b/llvm/lib/Object/MachOObjectFile.cpp
@@ -495,6 +495,19 @@ MachOObjectFile::getSymbolFileOffset(DataRefImpl Symb,
   return object_error::success;
 }
 
+error_code MachOObjectFile::getSymbolAlignment(DataRefImpl DRI,
+                                               uint32_t &Result) const {
+  uint32_t flags;
+  this->getSymbolFlags(DRI, flags);
+  if (flags & SymbolRef::SF_Common) {
+    SymbolTableEntryBase Entry = getSymbolTableEntryBase(this, DRI);
+    Result = 1 << MachO::GET_COMM_ALIGN(Entry.Flags);
+  } else {
+    Result = 0;
+  }
+  return object_error::success;
+}
+
 error_code MachOObjectFile::getSymbolSize(DataRefImpl DRI,
                                           uint64_t &Result) const {
   uint64_t BeginOffset;
@@ -609,8 +622,12 @@ error_code MachOObjectFile::getSymbolFlags(DataRefImpl DRI,
 
   if (MachOType & MachO::NlistMaskExternal) {
     Result |= SymbolRef::SF_Global;
-    if ((MachOType & MachO::NlistMaskType) == MachO::NListTypeUndefined)
-      Result |= SymbolRef::SF_Common;
+    if ((MachOType & MachO::NlistMaskType) == MachO::NListTypeUndefined) {
+      uint64_t Value;
+      getSymbolAddress(DRI, Value);
+      if (Value)
+        Result |= SymbolRef::SF_Common;
+    }
   }
 
   if (MachOFlags & (MachO::NListDescWeakRef | MachO::NListDescWeakDef))