Metering for Bulk Memory Opcodes + Opcode Version

[laurci]

Bulk memory opcodes and versioned opcode configuration

Summary

This PR adds support for WebAssembly bulk-memory operations and makes opcode configuration explicitly versioned across the Rust and C APIs.

• Add OpcodeVersion and OpcodeConfig; V1 remains the default legacy opcode set, while V2 enables memory.copy and memory.fill.
• Remove unsupported exception-handling, reference-type, and table-manipulation instructions from the V2 whitelist. memory.init and data.drop remain unsupported.
• Meter bulk-memory operations in both the production Wasmer executor and the experimental executor with independent base and per-byte costs for copy and fill.
• Refactor opcode-cost handling into dedicated shared structures and replace the former opcode-usage mechanism.
• Harden the C ABI with explicit repr(C) mirrors for compilation options and opcode costs, and replace vm_exec_set_opcode_costs with version-aware vm_exec_set_opcode_config.
• Regenerate VM hooks, remove the retired hook entries, and update the Rust toolchain to 1.98.

Gas accounting

For both memory.copy and memory.fill, the charged gas is:

base_cost + (byte_count * per_byte_cost)

The base cost applies to zero-byte operations as well. The instrumentation preserves the size operand on the WebAssembly stack.

Compatibility

• Existing users remain on OpcodeVersion::V1 by default and cannot instantiate modules that use bulk-memory operations.
• Consumers that need memory.copy or memory.fill must configure OpcodeVersion::V2 with the corresponding opcode costs.
• C API consumers must migrate from vm_exec_set_opcode_costs to vm_exec_set_opcode_config, passing the opcode-version code and the ABI-safe opcode-cost structure.

Tests

• Add production and experimental executor tests covering base costs, per-byte costs, zero-byte operations, and preservation of a local size operand.
• Add an opcode-version test confirming that a memory.copy module is rejected by V1 and accepted by V2.

[Copilot]

Copilot review overview

🟡 Changes recommended

Critical metering correctness, cache enforcement, import compatibility, and public ABI regressions remain unresolved.

Get a fresh assessment by requesting another Copilot review.

Review effort: Balanced
Findings: 8

Open (8)

• Removing managed crypto hooks breaks the public C/Wasm ABI · New
• Renaming the opcode cost symbol breaks existing native consumers · New
• Removing hook table fields breaks the public ABI layout · New
• Removing pairing imports breaks existing Wasm modules · New
• Cached modules bypass opcode version configuration checks · New
• Missing i32-to-i64 conversion breaks backup GlobalSet typing · New
• Missing i64-to-i32 conversion breaks injected GlobalGet typing · New
• Removing VM hooks breaks host and contract compatibility · New