[lld] r233783 - [ELF][Hexagon] Add comments related to hexagon relocations.

[Shankar Easwaran]

Author: shankare
Date: Tue Mar 31 22:07:01 2015
New Revision: 233783

URL: http://llvm.org/viewvc/llvm-project?rev=233783&view=rev
Log:
[ELF][Hexagon] Add comments related to hexagon relocations.

No functional changes.

Modified:
    lld/trunk/lib/ReaderWriter/ELF/Hexagon/HexagonEncodings.h
    lld/trunk/lib/ReaderWriter/ELF/Hexagon/HexagonRelocationFunctions.h

Modified: lld/trunk/lib/ReaderWriter/ELF/Hexagon/HexagonEncodings.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/Hexagon/HexagonEncodings.h?rev=233783&r1=233782&r2=233783&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/ELF/Hexagon/HexagonEncodings.h (original)
+++ lld/trunk/lib/ReaderWriter/ELF/Hexagon/HexagonEncodings.h Tue Mar 31 22:07:01 2015
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 Instruction insn_encodings[] = {
+  // InsnMask   CompareMask BitMask IsDuplexInstruction
   { 0xffe00004, 0x40000000, 0x20f8, 0x0 },
   { 0xffe03080, 0x9ca03080, 0xf60, 0x0 },
   { 0xf9e00000, 0x48c00000, 0x61f20ff, 0x0 },

Modified: lld/trunk/lib/ReaderWriter/ELF/Hexagon/HexagonRelocationFunctions.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/Hexagon/HexagonRelocationFunctions.h?rev=233783&r1=233782&r2=233783&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/ELF/Hexagon/HexagonRelocationFunctions.h (original)
+++ lld/trunk/lib/ReaderWriter/ELF/Hexagon/HexagonRelocationFunctions.h Tue Mar 31 22:07:01 2015
@@ -16,12 +16,15 @@
 namespace lld {
 namespace elf {
 
-/// \brief HexagonInstruction which is used to store various values
+/// \brief Applying fixup on Hexagon requires the relocator to fetch the fixup
+/// mask from the instruction. To fetch the fixup encoding, the linker uses a
+/// static array that contains the instruction mask, the compare mask and the
+/// relocation mask.
 typedef struct {
-  uint32_t insnMask;
-  uint32_t insnCmpMask;
-  uint32_t insnBitMask;
-  bool isDuplex;
+  uint32_t insnMask;    // Instruction mask.
+  uint32_t insnCmpMask; // Compare mask.
+  uint32_t insnBitMask; // Relocation mask.
+  bool isDuplex;        // Indicates if the instruction is a duplex instruction.
 } Instruction;
 
 #include "HexagonEncodings.h"
@@ -37,7 +40,7 @@ inline uint32_t findv4bitmask(uint8_t *l
     if (((insn_encodings[i].insnMask) & insn) == insn_encodings[i].insnCmpMask)
       return insn_encodings[i].insnBitMask;
   }
-  llvm_unreachable("found unknown instruction");
+  llvm_unreachable("found unknown Hexagon instruction");
 }
 
 } // elf