// parseInst converts the provided LLVM IR instruction into an equivalent Go AST
// node (a statement).
func parseInst(inst llvm.Value) (ast.Stmt, error) {
// TODO: Remove debug output.
if flagVerbose {
fmt.Println("parseInst:")
fmt.Println(" nops:", inst.OperandsCount())
inst.Dump()
fmt.Println()
}
// Assignment operation.
// %foo = ...
opcode := inst.InstructionOpcode()
if _, err := getResult(inst); err == nil {
// Binary Operations
switch opcode {
case llvm.Add, llvm.FAdd:
return parseBinOp(inst, token.ADD)
case llvm.Sub, llvm.FSub:
return parseBinOp(inst, token.SUB)
case llvm.Mul, llvm.FMul:
return parseBinOp(inst, token.MUL)
case llvm.UDiv, llvm.SDiv, llvm.FDiv:
// TODO: Handle signed and unsigned div separately.
return parseBinOp(inst, token.QUO)
case llvm.URem, llvm.SRem, llvm.FRem:
// TODO: Handle signed and unsigned mod separately.
return parseBinOp(inst, token.REM)
// Bitwise Binary Operations
case llvm.Shl:
return parseBinOp(inst, token.SHL)
case llvm.LShr, llvm.AShr:
// TODO: Handle logical and arithmetic shift right separately.
return parseBinOp(inst, token.SHR)
case llvm.And:
return parseBinOp(inst, token.AND)
case llvm.Or:
return parseBinOp(inst, token.OR)
case llvm.Xor:
return parseBinOp(inst, token.XOR)
// Other Operators
case llvm.ICmp, llvm.FCmp:
pred, err := getCmpPred(inst)
if err != nil {
return nil, errutil.Err(err)
}
return parseBinOp(inst, pred)
}
}
return nil, errutil.Newf("support for LLVM IR instruction %q not yet implemented", prettyOpcode(opcode))
}
// addTerm adds the provided terminator instruction to the basic block. If the
// terminator instruction doesn't have a target basic block (e.g. ret) it is
// parsed and added to the statements list of the basic block instead.
func (bb *basicBlock) addTerm(term llvm.Value) error {
// TODO: Check why there is no opcode in the llvm library for the resume
// terminator instruction.
switch opcode := term.InstructionOpcode(); opcode {
case llvm.Ret:
// The return instruction doesn't have any target basic blocks so treat it
// like a regular instruction and append it to the list of statements.
ret, err := parseRetInst(term)
if err != nil {
return err
}
bb.stmts = append(bb.stmts, ret)
case llvm.Br, llvm.Switch, llvm.IndirectBr, llvm.Invoke, llvm.Unreachable:
// Parse the terminator instruction during the control flow analysis.
bb.term = term
default:
return errutil.Newf("non-terminator instruction %q at end of basic block", prettyOpcode(opcode))
}
return nil
}
