+buildExpr (Var n) = do
+ binds <- ask
+ case binds Map.!? n of
+ Just x -> pure x
+ Nothing -> error $ "'" <> n <> "' doesn't exist in scope"
+
+buildExpr (BinOp op a b) = do
+ opA <- buildExpr a
+ opB <- buildExpr b
+ tmp <- instr opA opB
+ if isCmp
+ then uitofp tmp Type.double
+ else return tmp
+ where isCmp
+ | Cmp _ <- op = True
+ | otherwise = False
+ instr = case op of
+ K.Add -> fadd
+ K.Sub -> fsub
+ K.Mul -> fmul
+ K.Cmp LT -> fcmp OLT
+ K.Cmp GT -> fcmp OGT
+ K.Cmp EQ -> fcmp OEQ
+
+buildExpr (Call callee params) = do
+ paramOps <- mapM buildExpr params
+ let nam = fromString callee
+ -- get a pointer to the function
+ typ = FunctionType Type.double (replicate (length params) Type.double) False
+ ptrTyp = Type.PointerType typ (AddrSpace 0)
+ ref = GlobalReference ptrTyp nam
+ call (ConstantOperand ref) (zip paramOps (repeat []))
+
+buildExpr (If cond thenE elseE) = mdo
+ _ifB <- block `named` "if"
+
+ -- since everything is a double, false == 0
+ let zero = ConstantOperand (Float (Double 0))
+ condV <- buildExpr cond
+ cmp <- fcmp ONE zero condV `named` "cmp"
+
+ condBr cmp thenB elseB
+
+ thenB <- block `named` "then"
+ thenOp <- buildExpr thenE
+ br mergeB
+
+ elseB <- block `named` "else"
+ elseOp <- buildExpr elseE
+ br mergeB
+
+ mergeB <- block `named` "ifcont"
+ phi [(thenOp, thenB), (elseOp, elseB)]
+
+buildExpr (For name init cond mStep body) = mdo
+ preheaderB <- block `named` "preheader"
+
+ initV <- buildExpr init `named` "init"
+
+ -- build the condition expression with 'i' in the bindings
+ initCondV <- withReaderT (Map.insert name initV) $
+ (buildExpr cond >>= fcmp ONE zero) `named` "initcond"
+
+ -- skip the loop if we don't meet the condition with the init
+ condBr initCondV loopB afterB
+
+ loopB <- block `named` "loop"
+ i <- phi [(initV, preheaderB), (nextVar, loopB)] `named` "i"
+
+ -- build the body expression with 'i' in the bindings
+ withReaderT (Map.insert name i) $ buildExpr body `named` "body"
+
+ -- default to 1 if there's no step defined
+ stepV <- case mStep of
+ Just step -> buildExpr step
+ Nothing -> return $ ConstantOperand (Float (Double 1))
+
+ nextVar <- fadd i stepV `named` "nextvar"
+
+ let zero = ConstantOperand (Float (Double 0))
+ -- again we need 'i' in the bindings
+ condV <- withReaderT (Map.insert name i) $
+ (buildExpr cond >>= fcmp ONE zero) `named` "cond"
+ condBr condV loopB afterB
+
+ afterB <- block `named` "after"
+ -- since a for loop doesn't really have a value, return 0
+ return $ ConstantOperand (Float (Double 0))
+