[RISCV][MC] Reject bare symbols for the simm6 and simm6nonzero operand types

[apazos]

Summary

Fixed assertions due to invalid fixup when encoding compressed instructions
(c.addi, c.addiw, c.li, c.andi) with bare symbols with/without modifiers.

This matches GAS behavior as well.

This bug was uncovered by a LLVM MC Disassembler Protocol Buffer Fuzzer
for the RISC-V assembly language.

[asb]

Thanks, looks good to me. Note that the IsValid local variables can now be removed.

lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

330 ↗

(On Diff #165170)

IsValid can now be deleted.

341 ↗

(On Diff #165170)

IsValid can now be deleted.

[apazos]

Removed unused var.

llvm/trunk/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

return IsConstantImm && isUInt<5>(Imm) && (Imm != 0) &&
            VK == RISCVMCExpr::VK_RISCV_None;
   }
 
   bool isSImm6() const {
     if (!isImm())
       return false;
     RISCVMCExpr::VariantKind VK;
     int64_t Imm;
-    bool IsValid;
     bool IsConstantImm = evaluateConstantImm(Imm, VK);
-    if (!IsConstantImm)
-      IsValid = RISCVAsmParser::classifySymbolRef(getImm(), VK, Imm);
-    else
-      IsValid = isInt<6>(Imm);
-    return IsValid &&
-           (VK == RISCVMCExpr::VK_RISCV_None || VK == RISCVMCExpr::VK_RISCV_LO);
+    return IsConstantImm && isInt<6>(Imm) &&
+           VK == RISCVMCExpr::VK_RISCV_None;
   }
 
   bool isSImm6NonZero() const {
     if (!isImm())
       return false;
     RISCVMCExpr::VariantKind VK;
     int64_t Imm;
-    bool IsValid;
     bool IsConstantImm = evaluateConstantImm(Imm, VK);
-    if (!IsConstantImm)
-      IsValid = RISCVAsmParser::classifySymbolRef(getImm(), VK, Imm);
-    else
-      IsValid = ((Imm != 0) && isInt<6>(Imm));
-    return IsValid &&
-           (VK == RISCVMCExpr::VK_RISCV_None || VK == RISCVMCExpr::VK_RISCV_LO);
+    return IsConstantImm && isInt<6>(Imm) && (Imm != 0) &&
+           VK == RISCVMCExpr::VK_RISCV_None;
   }
 
   bool isCLUIImm() const {
     if (!isImm())
       return false;
     int64_t Imm;
     RISCVMCExpr::VariantKind VK;
     bool IsConstantImm = evaluateConstantImm(Imm, VK);

llvm/trunk/test/MC/RISCV/rv32c-invalid.s

 
 ## uimmlog2xlennonzero
 c.slli t0, 64 # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 31]
 c.srli a0, 32 # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 31]
 c.srai a0, 0  # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 31]
 
 ## simm6
 c.li t0, 128 # CHECK: :[[@LINE]]:10: error: immediate must be an integer in the range [-32, 31]
+c.li t0, foo # CHECK: :[[@LINE]]:10: error: immediate must be an integer in the range [-32, 31]
+c.li t0, %lo(foo) # CHECK: :[[@LINE]]:10: error: immediate must be an integer in the range [-32, 31]
+c.li t0, %hi(foo) # CHECK: :[[@LINE]]:10: error: immediate must be an integer in the range [-32, 31]
 c.andi a0, -33 # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [-32, 31]
+c.andi a0, foo # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [-32, 31]
+c.andi a0, %lo(foo) # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [-32, 31]
+c.andi a0, %hi(foo) # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [-32, 31]
 
 ## simm6nonzero
 c.addi t0, 0 # CHECK: :[[@LINE]]:12: error: immediate must be non-zero in the range [-32, 31]
 c.addi t0, -33 # CHECK: :[[@LINE]]:12: error: immediate must be non-zero in the range [-32, 31]
 c.addi t0, 32 # CHECK: :[[@LINE]]:12: error: immediate must be non-zero in the range [-32, 31]
+c.addi t0, foo # CHECK: :[[@LINE]]:12: error: immediate must be non-zero in the range [-32, 31]
+c.addi t0, %lo(foo) # CHECK: :[[@LINE]]:12: error: immediate must be non-zero in the range [-32, 31]
+c.addi t0, %hi(foo) # CHECK: :[[@LINE]]:12: error: immediate must be non-zero in the range [-32, 31]
 
 ## c_lui_imm
 c.lui t0, 0 # CHECK: :[[@LINE]]:11: error: immediate must be in [0xfffe0, 0xfffff] or [1, 31]
 c.lui t0, 32 # CHECK: :[[@LINE]]:11: error: immediate must be in [0xfffe0, 0xfffff] or [1, 31]
 c.lui t0, 0xffffdf # CHECK: :[[@LINE]]:11: error: immediate must be in [0xfffe0, 0xfffff] or [1, 31]
 c.lui t0, 0x1000000 # CHECK: :[[@LINE]]:11: error: immediate must be in [0xfffe0, 0xfffff] or [1, 31]
 
 ## uimm8_lsb00

llvm/trunk/test/MC/RISCV/rv64c-invalid.s

 ## uimmlog2xlennonzero
 c.slli t0, 64 # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 63]
 c.srli a0, -1 # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 63]
 c.srai a0, 0  # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [1, 63]
 
 ## simm6
 c.addiw t0, -33 # CHECK: :[[@LINE]]:13: error: immediate must be an integer in the range [-32, 31]
 c.addiw t0, 32 # CHECK: :[[@LINE]]:13: error: immediate must be an integer in the range [-32, 31]
+c.addiw t0, foo # CHECK: :[[@LINE]]:13: error: immediate must be an integer in the range [-32, 31]
+c.addiw t0, %lo(foo) # CHECK: :[[@LINE]]:13: error: immediate must be an integer in the range [-32, 31]
+c.addiw t0, %hi(foo) # CHECK: :[[@LINE]]:13: error: immediate must be an integer in the range [-32, 31]
 
 ## uimm9_lsb000
 c.ldsp  ra, 512(sp) # CHECK: :[[@LINE]]:13: error: immediate must be a multiple of 8 bytes in the range [0, 504]
 c.sdsp  ra, -8(sp) # CHECK: :[[@LINE]]:13: error: immediate must be a multiple of 8 bytes in the range [0, 504]
 ## uimm8_lsb000
 c.ld  s0, -8(sp) # CHECK: :[[@LINE]]:11: error: immediate must be a multiple of 8 bytes in the range [0, 248]
 c.sd  s0, 256(sp) # CHECK: :[[@LINE]]:11: error: immediate must be a multiple of 8 bytes in the range [0, 248]