Tilde Requests

[gingerBill]

I will add to this as I go along when I see things which may be missing.

API

• Any function that takes a const char* also take a length where possible
  • Maybe using your convention of when ptrdiff_t is -1, it's NUL terminated
• Function Signature ABI handling
  • Documentation
  • Better Abstraction that handles it for you, maybe?
• f16 type
  • Even if it is just u16 internally or whatever
• Range bounds on values to improve generation of bounds checks
  • If a pointer-like array has a specific range to it, and an integer is know to have a specific range, then a bounds check may be omitted
• Minimum alignment of a TB_Node* (useful in some instructions that require an explicit alignment)

Instructions

• alloca equivalent
• tb_inst_ptr is missing
• tb_inst_sint/tb_inst_uint for types >64 bits (e.g. 128-bits)
• tb_inst_memmove
  • High Priority
• TB_(SHL|SHR|SAR) with slightly different to C semantics
  • Instead of C-like, I want Odin-like which is defined to have x<<2 == (x<<1)<<1
• TB_BSWAP work with floats
  • useful for endian specific types and file formats
• add/sub/mul with overflow check
  • Low priority, and for mul it can be done with TB_MULPAIR
• add/sub/mul with saturation
  • Extension to TB_ArithmeticBehavior maybe?
  • Very low priority
• fused multiply add (fma)
  • Very low priority
• nontemporal stores and loads
  • Low priority
• Fixed point arithmetic? (I'm not sure about this one)
  • Very low priority
• Prefetch (read/write data/instruction)
  • Very low priority
• WASM intrinsics (when WASM is needed)
  • wasm.memory.grow
  • wasm.memory.size
  • wasm.memory.atomic.wait32
  • wasm.memory.atomic.notify
• tb_inst_memzero helper?
  • Is this even a needed?

TB_API void tb_inst_memzero(TB_Function* f, TB_Node* dst, TB_Node* val, TB_Node* count, TB_CharUnits align, bool is_volatile) {
    tb_inst_memset(f, dst, tb_inst_uint(f, TB_TYPE_I8, 0), count, align, is_volatile);
}

"Intrinsics"

• cpu_relax
  • pause on amd64
  • isb on arm64
• x86_cpuid
• x86_xgetbv
• Valgrind client request
  • It's just a weird set of instructions that does nothing but Valgrind et al looks for

IR Debugging

• Linearized Textual IR Printer (not GraphViz)

Debug Information

• Set column information along with file and line information
• Ability to set scopes
• Enum Types
• Named types

Questions

• Does tb_inst_set_region_name require that the name passed is in unique to that function or does Tilde handle this?
• How to get the previous instruction?—i.e. of a region

[RealNeGate]

For the questions, currently tb_inst_set_region_name does not require unique names but it will bite you once i make the flattened IR form if you reuse the same name.

If you wanna know the previous "instructions" to a region, you can check the inputs list and it'll tell you all the predecessors, you can do tb_get_parent_region(region->inputs[i]) if you want the top of that predecessor, but the actual inputs[i] is almost always a projection (TB_PROJ) stemming from a branch, you can reach the branch with another ->inputs[0].

[RealNeGate]

There we go, linearized IR printing. It uses the TB_FuncOpt which is usually is preserved for optimizations but i might rename it because it's really just for analysis/transformations and flattening the IR is a form of analysis.

[gingerBill]

Feature Request:

• Debug type for functions
• From debug type, it can produce the function prototype type for the specified ABI.

[ngortheone]

@gingerBill @RealNeGate I have a crazy off-topic idea/question for you guys.
Odin is "done". So why not write a C compiler(or at least compiler backend) in Odin?

I imagine Odin will provide great productivity gains and correctness as well.

(I am currently playing with Odin and I love it, and I heard that GB wants to replace LLVM with Tilde)