[ELF][Hexagon] Add duplex to R_HEX_GOT_16_X

[bcain]

Summary

Building 'espresso' from llvm-test-suite revealed missing support
for duplex instructions with R_HEX_GOT_16_X.

[sidneym]

LGTM

[ruiu]

LGTM

lld/ELF/Arch/Hexagon.cpp

168

You can remove the extraneous parentheses after return. Also, 0x0 should probably be just 0. Thus

return (0xC000 & insn) == 0;

[MaskRay]

LGTM, with the return (0xC000 & insn) == 0; change.

[bcain]

Fixed per review comments: removed superfluous parens around return expression, changed 0x0 to just 0.

lld/ELF/Arch/Hexagon.cpp

case R_HEX_TPREL_LO16:
     return R_TLS;
   default:
     error(getErrorLocation(loc) + "unknown relocation (" + Twine(type) +
           ") against symbol " + toString(s));
     return R_NONE;
   }
 }
 
+static bool isDuplex(uint32_t insn) {
+  // Duplex forms have a fixed mask and parse bits 15:14 are always
+  // zero.  Non-duplex insns will always have at least one bit set in the
+  // parse field.
+  return (0xC000 & insn) == 0;
+}
+
 static uint32_t findMaskR6(uint32_t insn) {
   // There are (arguably too) many relocation masks for the DSP's
   // R_HEX_6_X type.  The table below is used to select the correct mask
   // for the given instruction.
   struct InstructionMask {
     uint32_t cmpMask;
     uint32_t relocMask;
   };
 
   static const InstructionMask r6[] = {
       {0x38000000, 0x0000201f}, {0x39000000, 0x0000201f},
       {0x3e000000, 0x00001f80}, {0x3f000000, 0x00001f80},
       {0x40000000, 0x000020f8}, {0x41000000, 0x000007e0},
       {0x42000000, 0x000020f8}, {0x43000000, 0x000007e0},
       {0x44000000, 0x000020f8}, {0x45000000, 0x000007e0},
       {0x46000000, 0x000020f8}, {0x47000000, 0x000007e0},
       {0x6a000000, 0x00001f80}, {0x7c000000, 0x001f2000},
       {0x9a000000, 0x00000f60}, {0x9b000000, 0x00000f60},
       {0x9c000000, 0x00000f60}, {0x9d000000, 0x00000f60},
       {0x9f000000, 0x001f0100}, {0xab000000, 0x0000003f},
       {0xad000000, 0x0000003f}, {0xaf000000, 0x00030078},
       {0xd7000000, 0x006020e0}, {0xd8000000, 0x006020e0},
       {0xdb000000, 0x006020e0}, {0xdf000000, 0x006020e0}};
 
-  // Duplex forms have a fixed mask and parse bits 15:14 are always
-  // zero.  Non-duplex insns will always have at least one bit set in the
-  // parse field.
-  if ((0xC000 & insn) == 0x0)
+  if (isDuplex(insn))
     return 0x03f00000;
 
   for (InstructionMask i : r6)
     if ((0xff000000 & insn) == i.cmpMask)
       return i.relocMask;
 
   error("unrecognized instruction for R_HEX_6 relocation: 0x" +
         utohexstr(insn));
if ((0xff000000 & insn) == 0x48000000)
     return 0x061f20ff;
   if ((0xff000000 & insn) == 0x49000000)
     return 0x061f3fe0;
   if ((0xff000000 & insn) == 0x78000000)
     return 0x00df3fe0;
   if ((0xff000000 & insn) == 0xb0000000)
     return 0x0fe03fe0;
 
+  if (isDuplex(insn))
+    return 0x03f00000;
+
   error("unrecognized instruction for R_HEX_16_X relocation: 0x" +
         utohexstr(insn));
   return 0;
 }
 
 static void or32le(uint8_t *p, int32_t v) { write32le(p, read32le(p) | v); }
 
 void Hexagon::relocate(uint8_t *loc, const Relocation &rel,

lld/test/ELF/hexagon-shared.s

 # R_HEX_GOT_11_X and R_HEX_GOT_32_6_X
 r2=add(pc,##_GLOBAL_OFFSET_TABLE_@PCREL)
 r0 = memw (r2+##bar@GOT)
 jumpr r0
 
 # R_HEX_GOT_16_X
 r0 = add(r1,##bar@GOT)
 
+# R_HEX_GOT_16_X, duplex
+{ r0 = add(r0,##bar@GOT)
+  memw(r0) = r2 }
+
+
 # foo is local so no plt will be generated
 foo:
   jumpr lr
 
 hidden_symbol:
   jumpr lr
 
 # R_HEX_32

 # PLT-NEXT: r28 = memw(r14+#0) }
 # PLT-NEXT: jumpr r28 }
 
 # TEXT:  8c 00 01 00 0001008c
 # TEXT: {   call 0x102d0 }
 # TEXT: if (p0) jump:nt 0x102d0
 # TEXT: r0 = #0 ; jump 0x102d0
 # TEXT: r0 = add(r1,##-65548)
+# TEXT: r0 = add(r0,##-65548); memw(r0+#0) = r2 }
 
 # GOT: .got:
 # GOT:  00 00 00 00 00000000 <unknown>
 
 # RELO: R_HEX_GLOB_DAT
 # RELO: R_HEX_32
 # RELO: Relocation section '.rela.plt' at offset 0x22c contains 2 entries:
 # RELO: R_HEX_JMP_SLOT {{.*}} foo
 # RELO-NEXT: R_HEX_JMP_SLOT {{.*}} bar
 # RELO-NOT: R_HEX_JMP_SLOT {{.*}} hidden
 
 # Make sure that no PLT is generated for a local call.
 # SYMBOLIC: Relocation section '.rela.plt' at offset 0x22c contains 1 entries:
 # SYMBOLIC: R_HEX_JMP_SLOT {{.*}} bar
 # SYMBOLIC-NOT: R_HEX_JMP_SLOT {{.*}} foo