bpf: initial 32-bit ALU encoding support in assembler

This patch adds instruction patterns for operations in BPF_ALU. After this,
assembler could recognize some 32-bit ALU statement. For example, those listed
int the unit test file.

Separate MOV patterns are unnecessary as MOV is ALU operation that could reuse
ALU encoding infrastructure, this patch removed those redundant patterns.

Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Yonghong Song <yhs@fb.com>
llvm-svn: 313961

1 files changed, 15 insertions, 0 deletions

diff --git a/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp b/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp
index a1d732c339e..f5b621f9f8f 100644
--- a/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp
+++ b/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp
@@ -79,6 +79,21 @@ static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
   return MCDisassembler::Success;
 }
 
+static const unsigned GPR32DecoderTable[] = {
+    BPF::W0,  BPF::W1,  BPF::W2,  BPF::W3,  BPF::W4,  BPF::W5,
+    BPF::W6,  BPF::W7,  BPF::W8,  BPF::W9,  BPF::W10, BPF::W11};
+
+static DecodeStatus DecodeGPR32RegisterClass(MCInst &Inst, unsigned RegNo,
+                                             uint64_t /*Address*/,
+                                             const void * /*Decoder*/) {
+  if (RegNo > 11)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = GPR32DecoderTable[RegNo];
+  Inst.addOperand(MCOperand::createReg(Reg));
+  return MCDisassembler::Success;
+}
+
 static DecodeStatus decodeMemoryOpValue(MCInst &Inst, unsigned Insn,
                                         uint64_t Address, const void *Decoder) {
   unsigned Register = (Insn >> 16) & 0xf;