Verify before printing

examples/arithmetic.rs

@@ -1,9 +1,9 @@
 use reid::compile;
 
-pub static EASY: &str = include_str!("./reid/easy.reid");
+pub static ARITHMETIC: &str = include_str!("./reid/arithmetic.reid");
 
 fn main() {
-    let text = match compile(EASY) {
+    let text = match compile(ARITHMETIC) {
         Ok(t) => t,
         Err(e) => panic!("{}", e),
     };

examples/reid/arithmetic.reid

@@ -3,8 +3,12 @@
 fn main() {
     let test = 9;
     let simpleAdd = 2 + 2;
-    let simpleMult = 7 * 2;
-    let arithmetic = 3 + 2 * 5 + 1 * 2;
+    let simpleMult = 7 * 2; // 14
+    let arithmetic = 3 + 2 * 5 + 1 * 2; // 15
+    
+    if simpleAdd < test {
+        return 3;
+    }
 
     return arithmetic + simpleMult * arithmetic;
 }

examples/reid/fibonacci.reid

@@ -1,17 +1,9 @@
-// Hello, comment here!
-
-import std::print;
-
+// Main
 fn main() {
-    let hello = 32 + {
-        2 + 3
-    };
-    let beep = hello + fibonacci();
-    return beep;
+    return fibonacci(10);
 }
 
 // Fibonacci
-
 fn fibonacci(value: i32) -> i32 {
     if value < 3 {
         return 1;

src/ast.rs

@@ -214,7 +214,7 @@ impl Parse for FunctionCallExpression {
 }
 
 #[derive(Debug, Clone)]
-pub struct IfExpression(Expression, pub Block, pub TokenRange);
+pub struct IfExpression(pub Expression, pub Block, pub TokenRange);
 
 impl Parse for IfExpression {
     fn parse(mut stream: TokenStream) -> Result<Self, Error> {

src/codegen/llvm.rs

@@ -1,6 +1,9 @@
+use std::borrow::BorrowMut;
 use std::ffi::{CStr, CString};
 use std::mem;
+use std::ptr::null_mut;
 
+use llvm_sys::analysis::LLVMVerifyModule;
 use llvm_sys::{
     core::*, prelude::*, LLVMBasicBlock, LLVMBuilder, LLVMContext, LLVMModule, LLVMType, LLVMValue,
 };
@@ -21,14 +24,16 @@ pub enum Error {
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub enum IRType {
     I32,
+    Boolean,
 }
 
 impl IRType {
-    fn in_context(&self, context: &mut IRContext) -> *mut LLVMType {
+    fn in_context(&self, context: &IRContext) -> *mut LLVMType {
         use IRType::*;
         unsafe {
             return match self {
                 I32 => LLVMInt32TypeInContext(context.context),
+                Boolean => LLVMInt1TypeInContext(context.context),
             };
         }
     }
@@ -38,14 +43,14 @@ impl IRType {
 pub struct IRValue(pub IRType, *mut LLVMValue);
 
 impl IRValue {
-    pub fn from_literal(literal: &ast::Literal, block: &mut IRBlock) -> Self {
+    pub fn from_literal(literal: &ast::Literal, module: &IRModule) -> Self {
         use ast::Literal;
         match literal {
             Literal::I32(v) => {
                 let ir_type = IRType::I32;
                 unsafe {
                     let ir_value = LLVMConstInt(
-                        ir_type.in_context(block.function.module.context),
+                        ir_type.in_context(module.context),
                         mem::transmute(*v as i64),
                         1,
                     );
@@ -102,7 +107,14 @@ impl<'a> IRModule<'a> {
     }
 
     pub fn print_to_string(&mut self) -> Result<&str, std::str::Utf8Error> {
-        unsafe { CStr::from_ptr(LLVMPrintModuleToString(self.module)).to_str() }
+        unsafe {
+            LLVMVerifyModule(
+                self.module,
+                llvm_sys::analysis::LLVMVerifierFailureAction::LLVMPrintMessageAction,
+                null_mut(),
+            );
+            CStr::from_ptr(LLVMPrintModuleToString(self.module)).to_str()
+        }
     }
 }
 
@@ -116,18 +128,17 @@ impl<'a> Drop for IRModule<'a> {
 }
 
 pub struct IRFunction<'a, 'b> {
-    module: &'b mut IRModule<'a>,
+    pub module: &'b IRModule<'a>,
     /// The actual function
     value: *mut LLVMValue,
 }
 
 impl<'a, 'b> IRFunction<'a, 'b> {
-    pub fn new(name: &String, module: &'b mut IRModule<'a>) -> IRFunction<'a, 'b> {
+    pub fn new(name: &String, module: &'b IRModule<'a>) -> IRFunction<'a, 'b> {
         unsafe {
             // TODO, fix later!
 
             let return_type = LLVMInt32TypeInContext(module.context.context);
-
             let mut argts = [];
             let func_type =
                 LLVMFunctionType(return_type, argts.as_mut_ptr(), argts.len() as u32, 0);
@@ -143,18 +154,15 @@ impl<'a, 'b> IRFunction<'a, 'b> {
 }
 
 pub struct IRBlock<'a, 'b, 'c> {
-    function: &'a mut IRFunction<'b, 'c>,
+    pub function: &'c IRFunction<'a, 'b>,
     blockref: *mut LLVMBasicBlock,
 }
 
 impl<'a, 'b, 'c> IRBlock<'a, 'b, 'c> {
-    pub fn new(function: &'a mut IRFunction<'b, 'c>) -> IRBlock<'a, 'b, 'c> {
+    pub fn new(function: &'c IRFunction<'a, 'b>, name: &CStr) -> IRBlock<'a, 'b, 'c> {
         unsafe {
-            let blockref = LLVMCreateBasicBlockInContext(
-                function.module.context.context,
-                into_cstring("entryblock").as_ptr(),
-            );
-            LLVMPositionBuilderAtEnd(function.module.context.builder, blockref);
+            let blockref =
+                LLVMCreateBasicBlockInContext(function.module.context.context, name.as_ptr());
 
             IRBlock { function, blockref }
         }
@@ -166,6 +174,7 @@ impl<'a, 'b, 'c> IRBlock<'a, 'b, 'c> {
         IRValue(rhs_t, rhs_v): IRValue,
     ) -> Result<IRValue, Error> {
         unsafe {
+            LLVMPositionBuilderAtEnd(self.function.module.context.builder, self.blockref);
             if lhs_t == rhs_t {
                 Ok(IRValue(
                     lhs_t,
@@ -188,6 +197,7 @@ impl<'a, 'b, 'c> IRBlock<'a, 'b, 'c> {
         IRValue(rhs_t, rhs_v): IRValue,
     ) -> Result<IRValue, Error> {
         unsafe {
+            LLVMPositionBuilderAtEnd(self.function.module.context.builder, self.blockref);
             if lhs_t == rhs_t {
                 Ok(IRValue(
                     lhs_t,
@@ -204,8 +214,33 @@ impl<'a, 'b, 'c> IRBlock<'a, 'b, 'c> {
         }
     }
 
-    pub fn add_return(self, value: Option<IRValue>) {
+    pub fn less_than(
+        &mut self,
+        IRValue(lhs_t, lhs_v): IRValue,
+        IRValue(rhs_t, rhs_v): IRValue,
+    ) -> Result<IRValue, Error> {
         unsafe {
+            LLVMPositionBuilderAtEnd(self.function.module.context.builder, self.blockref);
+            if lhs_t == rhs_t {
+                Ok(IRValue(
+                    IRType::Boolean,
+                    LLVMBuildICmp(
+                        self.function.module.context.builder,
+                        llvm_sys::LLVMIntPredicate::LLVMIntULT,
+                        lhs_v,
+                        rhs_v,
+                        c"IntULT".as_ptr(),
+                    ),
+                ))
+            } else {
+                Err(Error::TypeMismatch(lhs_t, rhs_t))
+            }
+        }
+    }
+
+    pub fn add_return(&mut self, value: Option<IRValue>) {
+        unsafe {
+            LLVMPositionBuilderAtEnd(self.function.module.context.builder, self.blockref);
             if let Some(IRValue(_, value)) = value {
                 LLVMBuildRet(self.function.module.context.builder, value);
             } else {
@@ -213,6 +248,30 @@ impl<'a, 'b, 'c> IRBlock<'a, 'b, 'c> {
             }
         }
     }
+
+    pub fn branch(
+        &mut self,
+        IRValue(_, condition): IRValue,
+        then_block: &mut IRBlock,
+        else_block: &mut IRBlock,
+    ) {
+        unsafe {
+            LLVMPositionBuilderAtEnd(self.function.module.context.builder, self.blockref);
+            LLVMBuildCondBr(
+                self.function.module.context.builder,
+                condition,
+                then_block.blockref,
+                else_block.blockref,
+            );
+        }
+    }
+
+    pub fn move_into(&mut self, block: &mut IRBlock) {
+        unsafe {
+            LLVMPositionBuilderAtEnd(self.function.module.context.builder, self.blockref);
+            LLVMBuildBr(self.function.module.context.builder, block.blockref);
+        }
+    }
 }
 
 impl<'a, 'b, 'c> Drop for IRBlock<'a, 'b, 'c> {

src/codegen/mod.rs

@@ -6,7 +6,7 @@ use llvm::{Error, IRBlock, IRContext, IRFunction, IRModule, IRValue};
 
 use crate::{
     ast::{
-        BinaryOperator, Block, BlockLevelStatement, Expression, ExpressionKind, FunctionDefinition,
+        Block, BlockLevelStatement, Expression, ExpressionKind, FunctionDefinition, IfExpression,
         LetStatement, ReturnType,
     },
     TopLevelStatement,
@@ -41,21 +41,30 @@ impl TopLevelStatement {
 impl FunctionDefinition {
     fn codegen(&self, scope: &mut ScopeData, module: &mut IRModule) {
         let FunctionDefinition(signature, block, _) = self;
-        let mut ir_function = IRFunction::new(&signature.name, module);
-        let ir_block = IRBlock::new(&mut ir_function);
-        block.codegen(scope.with_block(ir_block));
+        let ir_function = IRFunction::new(&signature.name, module);
+
+        let ir_block = IRBlock::new(&ir_function, c"entry");
+        let mut scope = scope.inner(ir_block);
+        if let Some((_, val)) = block.codegen(&mut scope) {
+            scope.block.add_return(Some(val));
+        } else {
+            scope.block.add_return(None);
+        }
     }
 }
 
 impl Block {
-    fn codegen(&self, mut scope: Scope) {
+    #[must_use]
+    fn codegen(&self, scope: &mut Scope) -> Option<(ReturnType, IRValue)> {
         for statement in &self.0 {
-            statement.codegen(&mut scope);
+            statement.codegen(scope);
         }
 
-        if let Some((_, return_exp)) = &self.1 {
-            let value = return_exp.codegen(&mut scope);
-            scope.block.add_return(Some(value));
+        if let Some((ret_type, return_exp)) = &self.1 {
+            let value = return_exp.codegen(scope);
+            Some((*ret_type, value))
+        } else {
+            None
         }
     }
 }
@@ -83,7 +92,7 @@ impl Expression {
 
         use ExpressionKind::*;
         match kind {
-            Literal(lit) => IRValue::from_literal(lit, &mut scope.block),
+            Literal(lit) => IRValue::from_literal(lit, &scope.block.function.module),
             VariableName(v) => scope.data.fetch(v),
             Binop(op, lhs, rhs) => {
                 let lhs = lhs.codegen(scope);
@@ -92,10 +101,30 @@ impl Expression {
                 match op {
                     Add => scope.block.add(lhs, rhs).unwrap(),
                     Mult => scope.block.mult(lhs, rhs).unwrap(),
+                    LessThan => scope.block.less_than(lhs, rhs).unwrap(),
                     _ => panic!("operator not supported: {:?}", op),
                 }
             }
-            _ => panic!("expression type not supported"),
+            IfExpr(ifx) => {
+                let IfExpression(expr, block, _) = ifx.as_ref();
+                let condition = expr.codegen(scope);
+
+                let mut thenb = IRBlock::new(scope.block.function, c"then");
+                let mut afterb = IRBlock::new(scope.block.function, c"merge");
+
+                scope.block.branch(condition, &mut thenb, &mut afterb);
+                scope.block = afterb;
+
+                let mut then = scope.inner(thenb);
+                match block.codegen(&mut then) {
+                    Some((ReturnType::Hard, v)) => then.block.add_return(Some(v)),
+                    _ => then.block.move_into(&mut scope.block),
+                }
+
+                IRValue::from_literal(&crate::ast::Literal::I32(1), scope.block.function.module)
+            }
+            BlockExpr(_) => panic!("block expr not supported"),
+            FunctionCall(_) => panic!("function call expr not supported"),
         }
     }
 }
@@ -112,11 +141,12 @@ impl ScopeData {
         }
     }
 
-    fn with_block<'a, 'b, 'c>(&self, block: IRBlock<'a, 'b, 'c>) -> Scope<'a, 'b, 'c> {
-        Scope {
-            data: self.clone(),
-            block,
+    fn with_block<'a, 'b, 'c>(self, block: IRBlock<'a, 'b, 'c>) -> Scope<'a, 'b, 'c> {
+        Scope { data: self, block }
     }
+
+    fn inner<'a, 'b, 'c>(&self, block: IRBlock<'a, 'b, 'c>) -> Scope<'a, 'b, 'c> {
+        self.clone().with_block(block)
     }
 
     fn fetch(&self, name: &String) -> IRValue {
@@ -138,3 +168,9 @@ struct Scope<'a, 'b, 'c> {
     data: ScopeData,
     block: IRBlock<'a, 'b, 'c>,
 }
+
+impl<'a, 'b, 'c> Scope<'a, 'b, 'c> {
+    fn inner(&self, block: IRBlock<'a, 'b, 'c>) -> Scope<'a, 'b, 'c> {
+        self.data.clone().with_block(block)
+    }
+}