more codegen

Cargo.lock

@@ -109,6 +109,7 @@ dependencies = [
  "iced-x86",
  "object",
  "parser",
+ "rustc-hash",
 ]
 
 [[package]]

analysis/src/ir.rs

@@ -104,7 +104,7 @@ pub struct RegisterData<'cx> {
     pub name: Option<Symbol>,
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Register(pub u32);
 
 #[derive(Debug, Clone)]
@@ -245,6 +245,14 @@ impl ConstValue {
     pub fn u64(int: u64) -> Self {
         Self::Int(int.into())
     }
+
+    pub fn as_i32(self) -> i32 {
+        match self {
+            Self::StaticPtr(_) => panic!("StaticPtr cannot be converted to integer"),
+            Self::Void => panic!("Void cannot be converted to integer"),
+            Self::Int(int) => int.try_into().unwrap(),
+        }
+    }
 }
 
 impl Operand {

analysis/src/ir/pretty.rs

@@ -184,6 +184,8 @@ impl<W: Write> PrettyPrinter<W> {
             }
         }
 
+        writeln!(self.out, "}}")?;
+
         Ok(())
     }
 }

codegen/Cargo.toml

@@ -18,3 +18,4 @@ iced-x86 = { version = "1.18.0", default-features = false, features = [
 ] }
 object = { version = "0.31.1", features = ["write"] }
 parser = { path = "../parser" }
+rustc-hash = "1.1.0"

codegen/src/lib.rs

@@ -10,7 +10,7 @@ use object::{
 
 type Result<T, E = analysis::Error> = std::result::Result<T, E>;
 
-pub fn generate<'cx>(lcx: &LoweringCx<'cx>, ir: &Ir<'cx>) -> Result<()> {
+pub fn generate<'cx>(lcx: &'cx LoweringCx<'cx>, ir: &Ir<'cx>) -> Result<()> {
     let mut obj = Object::new(
         object::BinaryFormat::Elf,
         object::Architecture::X86_64,
@@ -61,11 +61,11 @@ pub fn generate<'cx>(lcx: &LoweringCx<'cx>, ir: &Ir<'cx>) -> Result<()> {
             "linking with `cc` failed"
         )));
     } else {
-        std::fs::remove_file("main.o").map_err(|err| {
-            analysis::Error::new_without_span(format!(
-                "failed to remove temporary file main.o: {err}"
-            ))
-        })?;
+        // std::fs::remove_file("main.o").map_err(|err| {
+        //     analysis::Error::new_without_span(format!(
+        //         "failed to remove temporary file main.o: {err}"
+        //     ))
+        // })?;
     }
 
     Ok(())

codegen/src/x86.rs

@@ -1,6 +1,13 @@
-use analysis::{ir::Func, LoweringCx};
-use iced_x86::{code_asm as x, IcedError};
+use analysis::{
+    ir::{BbIdx, ConstValue, Func, Operand, Register, Statement, StatementKind},
+    LoweringCx,
+};
+use iced_x86::{
+    code_asm::{self as x, CodeAssembler},
+    IcedError, Instruction,
+};
 use parser::Span;
+use rustc_hash::FxHashMap;
 
 use crate::Result;
 
@@ -17,16 +24,127 @@ impl<T> IcedErrExt for Result<T, IcedError> {
     }
 }
 
-pub fn generate_func<'cx>(_lcx: &LoweringCx<'cx>, func: &Func<'cx>) -> Result<Vec<u8>> {
+#[derive(Debug, Clone, Copy)]
+enum RegValue {
+    Stack { offset: u64 },
+}
+
+struct AsmCtxt<'cx> {
+    lcx: &'cx LoweringCx<'cx>,
+    a: CodeAssembler,
+    reg_map: FxHashMap<Register, RegValue>,
+    current_stack_offset: u64,
+    bb_idx: BbIdx,
+}
+
+impl<'cx> AsmCtxt<'cx> {
+    fn generate_func(&mut self, func: &Func<'cx>) -> Result<()> {
+        // TODO: Prologue
+
+        loop {
+            let bb = &func.bbs[self.bb_idx.as_usize()];
+            for stmt in &bb.statements {
+                let Statement {
+                    span: st_sp,
+                    ref kind,
+                } = *stmt;
+
+                match *kind {
+                    StatementKind::Alloca {
+                        reg,
+                        size,
+                        align: _,
+                    } => {
+                        // TODO: Align
+                        match size {
+                            Operand::Const(c) => {
+                                let offset = c.as_i32();
+                                self.a.sub(x::rsp, offset).sp(st_sp)?;
+                                self.current_stack_offset += offset as u64;
+                            }
+                            Operand::Reg(_) => todo!("dynamic alloca is not supported"),
+                        };
+                        self.reg_map.insert(
+                            reg,
+                            RegValue::Stack {
+                                offset: self.current_stack_offset,
+                            },
+                        );
+                    }
+                    StatementKind::Store {
+                        ptr,
+                        value,
+                        size,
+                        align,
+                    } => match ptr {
+                        Operand::Const(_) => todo!("const stores not implemented"),
+                        Operand::Reg(reg) => {
+                            let value = self.reg_map[&reg];
+                            let stack_offset = match value {
+                                RegValue::Stack { offset } => offset,
+                            };
+                            //let rhs = match value {
+                            //    Operand::Const(c) => {}
+                            //    Operand::Reg(reg) => {}
+                            //};
+
+                            // mov [rbp + OFFSET], RHS
+
+                            //self.a.add_instruction(Instruction::with2(Code::Mov, op0, op1))
+
+                            self.a.mov(x::ptr(x::rax), x::rbx);
+                        }
+                    },
+                    StatementKind::Load {
+                        result,
+                        ptr,
+                        size,
+                        align,
+                    } => todo!(),
+                    StatementKind::BinOp {
+                        kind,
+                        lhs,
+                        rhs,
+                        result,
+                    } => todo!(),
+                    StatementKind::UnaryOperation { rhs, kind, result } => todo!(),
+                    StatementKind::PtrOffset {
+                        result,
+                        reg,
+                        amount,
+                    } => todo!(),
+                    StatementKind::Call {
+                        result,
+                        func,
+                        ref args,
+                    } => todo!(),
+                }
+            }
+
+            todo!("next bbs");
+        }
+
+        Ok(())
+    }
+}
+
+pub fn generate_func<'cx>(lcx: &'cx LoweringCx<'cx>, func: &Func<'cx>) -> Result<Vec<u8>> {
     assert_eq!(func.arity, 0, "arguments??? in MY uwucc????");
 
-    let sp = func.def_span;
-    let mut a = x::CodeAssembler::new(64).sp(sp)?;
+    let fn_sp = func.def_span;
+    let mut a = CodeAssembler::new(64).sp(fn_sp)?;
 
-    a.xor(x::rax, x::rax).sp(sp)?;
-    a.ret().sp(sp)?;
+    let mut cx = AsmCtxt {
+        lcx,
+        a,
+        reg_map: FxHashMap::default(),
+        current_stack_offset: 0,
+        bb_idx: BbIdx(0),
+    };
 
-    let code = a.assemble(0x4000).sp(sp)?;
+    cx.generate_func(func)?;
+
+    let code = cx.a.assemble(0x4000).sp(fn_sp)?;
 
     Ok(code)
 }

notes.md

@@ -0,0 +1,69 @@
+# lowering
+
+This C program
+
+```c
+long main() {
+    long a = 0;
+    int b = 0;
+    return 0;
+}
+```
+
+should lower into the following unoptimized IR
+
+```llvmir
+def main() {
+  bb0:
+    %a = alloca, size=8, align=8
+    store %a, 0, size=8, align=8
+    %b = alloca, size=4, align=4
+    store %b, 0, size=4, align=4
+    ret 0
+}
+```
+
+this IR can then be lowered to very sane machine code ignoring stack alignment which also like matters
+
+```x86asm
+sub rbp, 8    ; a
+mov [rbp], 0
+sub rbp, 4    ; b
+xor rax, rax
+ret
+```
+
+---
+
+```c
+int main()
+{
+    int a = 1 + 3 * 4;
+    return 0;
+}
+```
+
+```llvmir
+def main() {
+  bb0:
+    %a = alloca, size=4, align=4
+    %1 = mul 3, 4
+    %2 = add 1, %1
+    store %a, %2, size=4, align=4
+    ret 0
+}
+```
+
+```x86asm
+sub rbp, 4  ; a
+sub rbp, 4  ; %1
+mov rbx, 3
+mul rbx, 4
+mov dword ptr [rbp], rbx
+sub rbp, 4  ; %2
+mov rbx, 1
+add rbx, dword ptr [rbp + 4]
+mov dword ptr [rbp + 8], dword ptr [rbp]
+xor rax, rax
+ret
+```