v0.2.4-pre-beta

Major Development Areas

Wave ABI

• Define a Wave-specific calling convention
• Completely separate the C ABI from the Wave ABI
• Define scalar argument and return passing rules
• Define pointer argument and return passing rules
• Define aggregate argument and return passing rules
• Separate object representation from ABI transport representation
• Define target-specific register classification
• Define stack argument passing rules
• Define stack and aggregate alignment rules
• Define padding handling rules
• Define indirect argument passing rules
• Define hidden return pointer rules
• Define function symbol rules
• Define name mangling rules
• Define symbol visibility rules
• Define export/import ABI contracts
• Define cross-module interface contracts
• Define ABI boundary handling rules for generic types
• Define ABI lowering rules for Wave-specific types such as variants
• Add an ABI versioning scheme
• Add ABI compatibility determination mechanisms

Target-Specific ABIs

• Define the x86_64 Wave ABI
• Define the AArch64 Wave ABI
• Define the RV64 RISC-V Wave ABI
• Define the scope of the Wave ABI for WebAssembly
• Separate target-specific register, stack, alignment, and aggregate transport rules

C ABI Separation

• Keep the C ABI classifier independent from the Wave ABI
• Separate extern(c) and export(c) paths from the Wave ABI
• Separate the implementation structure so Wave ABI rules are not implicitly reused for the C ABI
• Separate C ABI aggregate classification from Wave ABI aggregate classification
• Preserve Clang-comparison-based C ABI regression fixtures

ABI Validation Infrastructure

• Add dedicated Wave ABI contract fixtures
• Separate C ABI fixtures from Wave ABI fixtures
• Add argument and return lowering validation
• Add aggregate transport validation
• Add register and stack placement validation
• Add symbol and name mangling validation
• Add cross-module ABI regression tests
• Add ABI version compatibility tests
• Add ABI contract tests for the LLVM backend
• Add an ABI contract fixture format reusable by Whale

Common Backend Contract

• Organize the type information required by ABI lowering in the frontend
• Establish a common contract so the LLVM backend and Whale follow the same Wave ABI definition
• Separate backend-specific implementation details from language-level ABI rules
• Organize ABI-related target metadata structures
• Establish a foundation for comparing ABI results across backends

Documentation

• Add a Wave ABI specification
• Document the calling convention
• Document target-specific argument and return rules
• Document aggregate transport rules
• Document name mangling and symbol rules
• Document cross-module interfaces
• Document ABI rules for generics and Wave-specific types
• Document ABI versioning and compatibility policies
• Document the differences between the Wave ABI and the C ABI