more ir

analysis/src/ir.rs

@@ -0,0 +1,66 @@
+/// A low level IR used for codegen.
+/// 
+/// The following expression is lowered to the following IR:
+/// 
+/// ```c
+/// int i = 0;
+/// long l = 1;
+/// int y = ((int)&i)+l;
+/// ```
+/// 
+/// ```c
+/// int _0;   // i
+/// long _1;  // l
+/// int *_2;  // tmp &i
+/// int _3;   // tmp (int)&i
+/// int _4;   // tmp l (implicit cast to int)
+/// int _5;   // y
+/// 
+/// _0 = Const(0)
+/// _1 = Const(1)
+/// _2 = AddrOf(_0)
+/// _3 = Cast(Ptr, Int, _2)
+/// _4 = Cast(Long, Int, _1)
+/// _5 = _3 + _4
+/// ```
+
+use parser::Span;
+
+use crate::hir::Ty;
+
+struct Body {
+    locals: Vec<LocalDecl>,
+    statements: Vec<Statement>,
+}
+
+struct LocalDecl {
+    pub ty: Ty,
+}
+
+struct Statement {
+    pub span: Span,
+    pub kind: StatementKind,
+}
+
+enum StatementKind {
+    Assign(LValue, RValue),
+}
+
+enum RValue {
+    BinOp(BinOpKind, Operand),
+    Const,
+}
+
+enum BinOpKind {
+    Add,
+    Sub,
+    Mul,
+    Div,
+    Mod,
+}
+
+enum Operand {
+    Local(usize),
+}
+
+enum LValue {}

analysis/src/lib.rs

@@ -2,4 +2,5 @@
 #![warn(rust_2018_idioms)]
 
 mod hir;
+mod ir;
 mod lower;