Add R_HEX_B13_PCREL relocation support

[sidneym]

Summary

While the _X extended version of this relocation is documented there is no practical way to make use of it in the ISA.

[ruiu]

LGTM

ELF/Arch/Hexagon.cpp

static uint32_t applyMask(uint32_t Mask, uint32_t Data) {
   return Result;
 }
 
 RelExpr Hexagon::getRelExpr(RelType Type, const Symbol &S,
                             const uint8_t *Loc) const {
   switch (Type) {
   case R_HEX_B9_PCREL:
   case R_HEX_B9_PCREL_X:
+  case R_HEX_B13_PCREL:
   case R_HEX_B15_PCREL:
   case R_HEX_B15_PCREL_X:
   case R_HEX_B22_PCREL:
   case R_HEX_B22_PCREL_X:
   case R_HEX_B32_PCREL_X:
   case R_HEX_6_PCREL_X:
     return R_PC;
   default:
case R_HEX_32_6_X:
     or32le(Loc, applyMask(0x0fff3fff, Val >> 6));
     break;
   case R_HEX_B9_PCREL:
     or32le(Loc, applyMask(0x003000fe, Val >> 2));
     break;
   case R_HEX_B9_PCREL_X:
     or32le(Loc, applyMask(0x003000fe, Val & 0x3f));
     break;
+  case R_HEX_B13_PCREL:
+    or32le(Loc, applyMask(0x00202ffe, Val >> 2));
+    break;
   case R_HEX_B15_PCREL:
     or32le(Loc, applyMask(0x00df20fe, Val >> 2));
     break;
   case R_HEX_B15_PCREL_X:
     or32le(Loc, applyMask(0x00df20fe, Val & 0x3f));
     break;
   case R_HEX_B22_PCREL:
     or32le(Loc, applyMask(0x1ff3ffe, Val >> 2));

test/ELF/hexagon.s

 
 # R_HEX_B9_PCREL:
 {r0=#1 ; jump #_start}
 # CHECK: jump 0x11000
 
 # R_HEX_B9_PCREL_X:
 {r0=#1 ; jump ##_start}
 # CHECK: jump 0x11000
+
+# R_HEX_B13_PCREL
+if (r0 == #0) jump:t #_start
+# CHECK: if (r0==#0) jump:t 0x11000