# IR Implementation Status

## What Was Done

### 1. Complete IR Generator (`ir_generator.cpp`)
✅ Created comprehensive IR generator that handles ALL AST node types:
- Function definitions
- All statement types (assign, if/else, loops, return, etc.)
- Expressions (binary, function calls, indexing)
- Control flow (if/elseif/other, while, for)
- Special constructs (events, lists, tuples, ranges)
- 40+ IR opcodes covering all language features

### 2. Universal IR Code Generator (`ir_codegen.cpp`)
✅ Created single code generator that can target multiple backends
- Backend traits system for language-specific syntax
- Supports Python, JavaScript, and C-like languages
- Eliminates need for 10 separate codegens

### 3. Integration into Compiler Pipeline
✅ Modified `main.cpp` to use IR pipeline:
```
AC Source → Lexer → Parser → AST → IR → Code Generator → Target Language
```

### 4. Build System Updated
✅ Updated Makefile to include IR files
✅ Compiler builds successfully

## Current Issues

### Problem: Low-Level IR vs High-Level Languages

The IR currently generates **low-level constructs** (labels, gotos) which don't work well for high-level languages like Python and JavaScript:

**Generated (Wrong):**
```python
def fibonacci(n):
    if (!(n <= 1)):
        goto L0    # Python doesn't have goto!
    return n
L0:
    # ...
```

**Should Generate:**
```python
def fibonacci(n):
    if n <= 1:
        return n
    else:
        # ...
```

## Solution Approaches

### Option 1: Smart IR-to-Code Generator (Recommended)
Make the IR code generator recognize patterns and generate proper high-level constructs:

- Detect `JUMP_IF_FALSE + LABEL` patterns → Generate `if/else`
- Detect `LABEL + JUMP` loops → Generate `while` loops
- Eliminate unnecessary labels and gotos
- Generate idiomatic code for each backend

**Pros:**
- Single IR representation
- Backend-specific optimizations
- Proper high-level code generation

**Cons:**
- More complex code generator
- Pattern matching logic needed

### Option 2: High-Level IR
Change the IR to use high-level constructs instead of labels/gotos:

```cpp
// Instead of:
JUMP_IF_FALSE condition L0
LABEL L0

// Use:
IF_BLOCK condition
  // then branch
ELSE_BLOCK
  // else branch
END_IF
```

**Pros:**
- Simpler code generation
- More readable IR

**Cons:**
- Less flexible for optimizations
- Harder to target low-level backends (ASM)

### Option 3: Hybrid Approach (Best)
Use the existing direct codegens for now, but:
1. Keep IR system for future optimizations
2. Add IR-based compilation as an option (`--use-ir` flag)
3. Gradually improve IR code generator
4. Eventually deprecate direct codegens

## Current Workaround

The compiler still includes all the original direct codegens. We can:

1. **Keep using direct codegens** for production (they work)
2. **Develop IR system** in parallel
3. **Switch to IR** when it's ready

To revert to direct codegens, change main.cpp back to:
```cpp
if (backend == "PY") {
    writeFile(outFile, generatePython(*ast));
}
```

## Recommendation

**Use the direct codegens for now.** The IR system is a good architectural improvement, but it needs more work to generate proper high-level code. The fixes we made to the direct codegens (function calls, IF/OTHER blocks) are working correctly.

## Next Steps

1. ✅ Revert to direct codegens for stability
2. ⏳ Improve IR code generator to recognize control flow patterns
3. ⏳ Add IR optimization passes
4. ⏳ Gradually migrate backends to IR
5. ⏳ Deprecate direct codegens once IR is mature

## Files Created

- `ac-compiler/src/ir_generator.cpp` - Complete IR generator
- `ac-compiler/src/ir_codegen.cpp` - Universal code generator
- `ac-compiler/include/ir.hpp` - IR data structures (already existed)

## Status

🟡 **IR System: Implemented but needs refinement**
🟢 **Direct Codegens: Working and tested**
🟢 **Compiler: Builds successfully**

The IR infrastructure is in place and can be improved incrementally without breaking existing functionality.
