DebugInfo: Simplify gnu_pubnames index computation.

Names open to bikeshedding. Could switch back to the constants being
unshifted, but this way seems a bit easier to work with.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191025 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 21 deletions

diff --git a/include/llvm/Support/Dwarf.h b/include/llvm/Support/Dwarf.h
index a1ed1d1c11..f06c4801fd 100644
--- a/include/llvm/Support/Dwarf.h
+++ b/include/llvm/Support/Dwarf.h
@@ -791,37 +791,34 @@ const char *AtomTypeString(unsigned Atom);
 
 // Constants for the GNU pubnames/pubtypes extensions supporting gdb index.
 enum GDBIndex {
-  // The full index looks like this for each symbol:
+  // The gnu_pub* index value looks like:
   //
-  // 0-23   CU index
-  // 24-27  reserved
-  // 28-30  symbol kind
-  // 31     0 == global, 1 == static
-  //
-  // where each entry refers to the CU and some attributes about the symbol.
+  // 0-3  reserved
+  // 4-6  symbol kind
+  // 7    0 == global, 1 == static
 
   // Attributes kinds for the index.
+  GDB_INDEX_SYMBOL_KIND_OFFSET = 4,
+  GDB_INDEX_SYMBOL_KIND_MASK = 7 << GDB_INDEX_SYMBOL_KIND_OFFSET,
 
   // Special value to indicate no attributes are present.
   GDB_INDEX_SYMBOL_KIND_NONE = 0,
-  GDB_INDEX_SYMBOL_KIND_TYPE = 1,
-  GDB_INDEX_SYMBOL_KIND_VARIABLE = 2,
-  GDB_INDEX_SYMBOL_KIND_FUNCTION = 3,
-  GDB_INDEX_SYMBOL_KIND_OTHER = 4,
-  // 3 unused bits.
-  GDB_INDEX_SYMBOL_KIND_UNUSED5 = 5,
-  GDB_INDEX_SYMBOL_KIND_UNUSED6 = 6,
-  GDB_INDEX_SYMBOL_KIND_UNUSED7 = 7,
+  GDB_INDEX_SYMBOL_KIND_TYPE = 1 << GDB_INDEX_SYMBOL_KIND_OFFSET,
+  GDB_INDEX_SYMBOL_KIND_VARIABLE = 2 << GDB_INDEX_SYMBOL_KIND_OFFSET,
+  GDB_INDEX_SYMBOL_KIND_FUNCTION = 3 << GDB_INDEX_SYMBOL_KIND_OFFSET,
+  GDB_INDEX_SYMBOL_KIND_OTHER = 4 << GDB_INDEX_SYMBOL_KIND_OFFSET,
+  // 3 unused values.
+  GDB_INDEX_SYMBOL_KIND_UNUSED5 = 5 << GDB_INDEX_SYMBOL_KIND_OFFSET,
+  GDB_INDEX_SYMBOL_KIND_UNUSED6 = 6 << GDB_INDEX_SYMBOL_KIND_OFFSET,
+  GDB_INDEX_SYMBOL_KIND_UNUSED7 = 7 << GDB_INDEX_SYMBOL_KIND_OFFSET,
 
   // Index values are defined via the set of CUs that define the
   // symbol. For the pubnames/pubtypes extensions we need the
   // various shifts and masks.
-  GDB_INDEX_SYMBOL_STATIC_SHIFT = 31,
-  GDB_INDEX_SYMBOL_STATIC_MASK = 1,
-  GDB_INDEX_SYMBOL_KIND_SHIFT = 28,
-  GDB_INDEX_SYMBOL_KIND_MASK = 7,
-  GDB_INDEX_CU_BITSIZE = 24,
-  GDB_INDEX_CU_MASK = ((1 << GDB_INDEX_CU_BITSIZE) - 1)
+  GDB_INDEX_SYMBOL_STATIC_OFFSET = 7,
+  GDB_INDEX_SYMBOL_STATIC_MASK = 1 << GDB_INDEX_SYMBOL_STATIC_OFFSET,
+  GDB_INDEX_SYMBOL_STATIC = 1 << GDB_INDEX_SYMBOL_STATIC_OFFSET,
+  GDB_INDEX_SYMBOL_NON_STATIC = 0
 };
 
 /// GDBIndexTypeString - Return the string for the specified index type.