bpf: New decoder namespace for 32-bit subregister load/store
When -mattr=+alu32 passed to the disassembler, use decoder namespace for
32-bit subregister.
This is to disassemble load and store instructions in preferred B format
as described in previous commit:
w = *(u8 *) (r + off) // BPF_LDX | BPF_B
w = *(u16 *)(r + off) // BPF_LDX | BPF_H
w = *(u32 *)(r + off) // BPF_LDX | BPF_W
*(u8 *) (r + off) = w // BPF_STX | BPF_B
*(u16 *)(r + off) = w // BPF_STX | BPF_H
*(u32 *)(r + off) = w // BPF_STX | BPF_W
NOTE: all other instructions should still use the default decoder
namespace.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Yonghong Song <yhs@fb.com>
llvm-svn: 325990
diff --git a/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp b/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp
index 6fc87d7..e7790dd 100644
--- a/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp
+++ b/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp
@@ -35,6 +35,34 @@
/// A disassembler class for BPF.
class BPFDisassembler : public MCDisassembler {
public:
+ enum BPF_CLASS {
+ BPF_LD = 0x0,
+ BPF_LDX = 0x1,
+ BPF_ST = 0x2,
+ BPF_STX = 0x3,
+ BPF_ALU = 0x4,
+ BPF_JMP = 0x5,
+ BPF_RES = 0x6,
+ BPF_ALU64 = 0x7
+ };
+
+ enum BPF_SIZE {
+ BPF_W = 0x0,
+ BPF_H = 0x1,
+ BPF_B = 0x2,
+ BPF_DW = 0x3
+ };
+
+ enum BPF_MODE {
+ BPF_IMM = 0x0,
+ BPF_ABS = 0x1,
+ BPF_IND = 0x2,
+ BPF_MEM = 0x3,
+ BPF_LEN = 0x4,
+ BPF_MSH = 0x5,
+ BPF_XADD = 0x6
+ };
+
BPFDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
: MCDisassembler(STI, Ctx) {}
~BPFDisassembler() override = default;
@@ -43,6 +71,10 @@
ArrayRef<uint8_t> Bytes, uint64_t Address,
raw_ostream &VStream,
raw_ostream &CStream) const override;
+
+ uint8_t getInstClass(uint64_t Inst) const { return (Inst >> 56) & 0x7; };
+ uint8_t getInstSize(uint64_t Inst) const { return (Inst >> 59) & 0x3; };
+ uint8_t getInstMode(uint64_t Inst) const { return (Inst >> 61) & 0x7; };
};
} // end anonymous namespace
@@ -141,8 +173,17 @@
Result = readInstruction64(Bytes, Address, Size, Insn, IsLittleEndian);
if (Result == MCDisassembler::Fail) return MCDisassembler::Fail;
- Result = decodeInstruction(DecoderTableBPF64, Instr, Insn,
- Address, this, STI);
+ uint8_t InstClass = getInstClass(Insn);
+ if ((InstClass == BPF_LDX || InstClass == BPF_STX) &&
+ getInstSize(Insn) != BPF_DW &&
+ getInstMode(Insn) == BPF_MEM &&
+ STI.getFeatureBits()[BPF::ALU32])
+ Result = decodeInstruction(DecoderTableBPFALU3264, Instr, Insn, Address,
+ this, STI);
+ else
+ Result = decodeInstruction(DecoderTableBPF64, Instr, Insn, Address, this,
+ STI);
+
if (Result == MCDisassembler::Fail) return MCDisassembler::Fail;
switch (Instr.getOpcode()) {