[llvm] r325775 - [RISCV][NFC] Make logic in RISCVMCCodeEmitter::getImmOpValue more defensive

[Alex Bradbury via llvm-commits]

Author: asb
Date: Thu Feb 22 05:24:25 2018
New Revision: 325775

URL: http://llvm.org/viewvc/llvm-project?rev=325775&view=rev
Log:
[RISCV][NFC] Make logic in RISCVMCCodeEmitter::getImmOpValue more defensive

As pointed out by @sabuasal in a comment on D23568, the logic in  
RISCVMCCodeEmitter::getImmOpValue could be more defensive. Although with the  
current instruction definitions it is always the case that `VK_RISCV_LO` is  
always used with either an I- or S-format instruction, this may not always be  
the case in the future. Add a check to ensure we will get an assertion in  
debug builds if that changes.

Modified:
    llvm/trunk/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp

Modified: llvm/trunk/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp?rev=325775&r1=325774&r2=325775&view=diff
==============================================================================
--- llvm/trunk/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp (original)
+++ llvm/trunk/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp Thu Feb 22 05:24:25 2018
@@ -161,16 +161,24 @@ unsigned RISCVMCCodeEmitter::getImmOpVal
     case RISCVMCExpr::VK_RISCV_Invalid:
       llvm_unreachable("Unhandled fixup kind!");
     case RISCVMCExpr::VK_RISCV_LO:
-      FixupKind = MIFrm == RISCVII::InstFormatI ? RISCV::fixup_riscv_lo12_i
-                                                : RISCV::fixup_riscv_lo12_s;
+      if (MIFrm == RISCVII::InstFormatI)
+        FixupKind = RISCV::fixup_riscv_lo12_i;
+      else if (MIFrm == RISCVII::InstFormatS)
+        FixupKind = RISCV::fixup_riscv_lo12_s;
+      else
+        llvm_unreachable("VK_RISCV_LO used with unexpected instruction format");
       break;
     case RISCVMCExpr::VK_RISCV_HI:
       FixupKind = RISCV::fixup_riscv_hi20;
       break;
     case RISCVMCExpr::VK_RISCV_PCREL_LO:
-      FixupKind = MIFrm == RISCVII::InstFormatI
-                      ? RISCV::fixup_riscv_pcrel_lo12_i
-                      : RISCV::fixup_riscv_pcrel_lo12_s;
+      if (MIFrm == RISCVII::InstFormatI)
+        FixupKind = RISCV::fixup_riscv_pcrel_lo12_i;
+      else if (MIFrm == RISCVII::InstFormatS)
+        FixupKind = RISCV::fixup_riscv_pcrel_lo12_s;
+      else
+        llvm_unreachable(
+            "VK_RISCV_PCREL_LO used with unexpected instruction format");
       break;
     case RISCVMCExpr::VK_RISCV_PCREL_HI:
       FixupKind = RISCV::fixup_riscv_pcrel_hi20;