ps][microMIPS] Add R_MICROMIPS_PC21_S1 relocation

Differential Revision: http://reviews.llvm.org/D15526

llvm-svn: 270048
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
index 76afeb6..8292d6b 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
@@ -189,7 +189,15 @@
       return 0;
     }
     break;
-
+  case Mips::fixup_MICROMIPS_PC21_S1:
+    // Forcing a signed division because Value can be negative.
+    Value = (int64_t)Value / 2;
+    // We now check if Value can be encoded as a 21-bit signed immediate.
+    if (!isInt<21>(Value) && Ctx) {
+      Ctx->reportError(Fixup.getLoc(), "out of range PC21 fixup");
+      return 0;
+    }
+    break;
   }
 
   return Value;
@@ -343,6 +351,7 @@
     { "fixup_MICROMIPS_PC26_S1", 0,     26,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_PC19_S2", 0,     19,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_PC18_S3", 0,     18,   MCFixupKindInfo::FKF_IsPCRel },
+    { "fixup_MICROMIPS_PC21_S1", 0,     21,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_CALL16",  0,     16,   0 },
     { "fixup_MICROMIPS_GOT_DISP",        0,     16,   0 },
     { "fixup_MICROMIPS_GOT_PAGE",        0,     16,   0 },
@@ -411,6 +420,7 @@
     { "fixup_MICROMIPS_PC26_S1", 6,     26,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_PC19_S2",13,     19,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_PC18_S3",14,     18,   MCFixupKindInfo::FKF_IsPCRel },
+    { "fixup_MICROMIPS_PC21_S1",11,     21,   MCFixupKindInfo::FKF_IsPCRel },
     { "fixup_MICROMIPS_CALL16", 16,     16,   0 },
     { "fixup_MICROMIPS_GOT_DISP",        16,     16,   0 },
     { "fixup_MICROMIPS_GOT_PAGE",        16,     16,   0 },
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
index a5e6385..cdad7ce1 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
@@ -247,6 +247,8 @@
       return ELF::R_MICROMIPS_PC19_S2;
     case Mips::fixup_MICROMIPS_PC18_S3:
       return ELF::R_MICROMIPS_PC18_S3;
+    case Mips::fixup_MICROMIPS_PC21_S1:
+      return ELF::R_MICROMIPS_PC21_S1;
     case Mips::fixup_MIPS_PC19_S2:
       return ELF::R_MIPS_PC19_S2;
     case Mips::fixup_MIPS_PC18_S3:
@@ -608,7 +610,7 @@
   case ELF::R_MICROMIPS_TLS_TPREL_LO16:
   case ELF::R_MICROMIPS_GPREL7_S2:
   case ELF::R_MICROMIPS_PC23_S2:
-  case ELF::R_MICROMIPS_PC21_S2:
+  case ELF::R_MICROMIPS_PC21_S1:
   case ELF::R_MICROMIPS_PC26_S1:
   case ELF::R_MICROMIPS_PC18_S3:
   case ELF::R_MICROMIPS_PC19_S2:
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h b/llvm/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h
index 1a15a64..b4d8e94 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h
@@ -176,6 +176,9 @@
     // resulting in - R_MICROMIPS_PC18_S3
     fixup_MICROMIPS_PC18_S3,
 
+    // resulting in - R_MICROMIPS_PC21_S1
+    fixup_MICROMIPS_PC21_S1,
+
     // resulting in - R_MICROMIPS_CALL16
     fixup_MICROMIPS_CALL16,
 
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
index 7e0fc30..3806b68 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
@@ -384,7 +384,10 @@
   assert(MO.isExpr() &&
     "getBranchTarget21OpValueMM expects only expressions or immediates");
 
-  // TODO: Push fixup.
+  const MCExpr *FixupExpression = MCBinaryExpr::createAdd(
+      MO.getExpr(), MCConstantExpr::create(-4, Ctx), Ctx);
+  Fixups.push_back(MCFixup::create(0, FixupExpression,
+                                   MCFixupKind(Mips::fixup_MICROMIPS_PC21_S1)));
   return 0;
 }