In #3038 we introduced the initial version of the Cranelift CLIF-level differential fuzzer.

This fuzzer generates CLIF modules that are run on the interpreter and subsequently on the host machine (assuming no traps / invalid memory accesses) comparing the outputs of each run.

Roadmap:

• Initial introduction (Cranelift CLIF-level differential fuzzer #3038)
• Generating test inputs with control flow
  • Generate multiple blocks and basic jump instructions (Cranelift CLIF Fuzzer generate blocks and branches #3094)
  • Generate br_table's and other jump table jumps (Cranelift CLIF Fuzzer add jump tables and br_table #3299)
• Generating memory loads/stores
  • Stack
    • Interpreter Support (cranelift: Add stack support to the interpreter with virtual addresses #3187)
    • Fuzzer Support (fuzzgen: Generate stack load/store instructions #4438)
  • Heap
    • Interpreter Support (cranelift: Add heap support to the interpreter #3302)
    • Fuzzer Support
  • Table
    • Interpreter Support (cranelift: Implement table_addr in interpreter #4433)
    • Fuzzer Support
  • Symbols
    • Interpreter Support
    • Fuzzer Support
  • Others
    • Cross endianness loads/stores
    • notrap MemFlags
    • aligned MemFlags
    • readonly MemFlags
• Generating calls
  • Generating LibCall's (cranelift: Add LibCalls to the interpreter #4782)
  • Generating Function Calls
  • Indirect Function Calls
• Full coverage of arithmetic ops
  • Extend the codegen in the cranelift-meta crate to provide a table of acceptable opcodes and types
• Full coverage of SIMD ops
• Misc
  • Add SourceLoc to instructions
  • Add ValueLabels to instructions