adding backend agnostic IR

src/compiler/ir/ir.zig

@@ -0,0 +1,58 @@
+//! ## Intermediate Representation
+//!
+//! The IR is the compiler's target-independent shader representation. It keeps
+//! shader structure explicit while hiding SPIR-V's binary encoding and large
+//! instruction surface.
+//!
+//! `module.Module` owns types, constants, values, instructions, blocks, functions,
+//! interfaces, and resources in typed ID stores. Values are in SSA form: each value
+//! is defined by a constant, parameter, instruction, or `undef`.
+//!
+//! Control flow is represented with basic blocks and terminators. Phi-like values
+//! are modeled as block parameters, with branch edge arguments supplying incoming
+//! values. Blocks can also record structured selection or loop metadata.
+//!
+//! Use `Builder` to construct modules, `validator.validate` to check invariants,
+//! `cfg` for control-flow queries, `Rewriter` for common edits, and
+//! `parser`/`printer` for the textual IR format used by tests and debugging.
+//!
+//! Here's a simple text representation of a shader module that `parser.Parser` and `printer` can handle/produce:
+//! ```
+//! shader vertex @main
+//! {
+//!     @color: vec4[f32] = input[location(0), component(0), index(0)]
+//!     @out_color: vec4[f32] = output[location(0), component(0), index(0)]
+//!     %0: constant bool = true
+//!     %1: constant f32 = bits(0x3f800000)
+//!
+//!     fn @main() -> void
+//!     {
+//!         .entry():
+//!             %3: vec4[f32] = load_interface @color
+//!             conditional_branch %0, .pass(), .merge(%3)
+//!
+//!         .pass():
+//!             %4: vec4[f32] = composite_construct %1, %1, %1, %1
+//!             branch .merge(%4)
+//!
+//!         .merge(%2: vec4[f32]):
+//!             store_interface @out_color, %2
+//!             return
+//!     }
+//! }
+//! ```
+
+pub const Builder = @import("Builder.zig");
+pub const Rewriter = @import("Rewriter.zig");
+pub const cfg = @import("cfg.zig");
+pub const constant = @import("constant.zig");
+pub const id = @import("id.zig");
+pub const instruction = @import("instruction.zig");
+pub const module = @import("module.zig");
+pub const parser = @import("parser/parser.zig");
+pub const pass_manager = @import("pass_manager.zig");
+pub const printer = @import("printer.zig");
+pub const types = @import("type.zig");
+pub const validator = @import("validator/validator.zig");
+pub const value = @import("value.zig");
+pub const visitor = @import("visitor.zig");