/JitInspector

JIT codegen inspector for Unity

Primary LanguageC#MIT LicenseMIT

JIT Inspector

A tool for inspecting Mono JIT code in Unity.

Usage

Open the tool from the Window -> JIT Inspector View menu option.

JIT Configuration

You can configure the JIT using the following class:

#if ENABLE_MONO
using System.Text;
using System.Runtime.InteropServices;

internal static unsafe class MonoJitConfig
{
    private const string Optimizations = "-float32";

    [DllImport("__Internal")]
    private static extern void mono_jit_parse_options(int argc, byte** argv);

#if UNITY_EDITOR
    [UnityEditor.InitializeOnLoadMethod]
#else
    [UnityEngine.RuntimeInitializeOnLoadMethod(UnityEngine.RuntimeInitializeLoadType.SubsystemRegistration)]
#endif
    private static void ParseOptions()
    {
        fixed (byte* arg = Encoding.UTF8.GetBytes("-O=" + Optimizations + "\0"))
        {
            mono_jit_parse_options(1, &arg);
        }
    }
}
#endif

The Optimizations string is a comma-separated (without spaces) list of optimization passes for the JIT to perform. Prefixing an optimization with a minus (-) will disable it.

You may use all to enable all optimizations and -all to disable all optimizations.

Entries later in the list will override entries before them, meaning -branch,branch will result in branch being enabled. -all,branch will result in only branch being enabled.

Available optimization passes are:

Name Description Enabled By Default
peephole Peephole postpass Yes
branch Branch optimizations Yes
inline Inline method calls Yes
cfold Constant folding Yes
consprop Constant propagation Yes
copyprop Copy propagation Yes
deadce Dead code elimination Yes
linears Linear scan global reg allocation Yes
cmov Conditional moves Yes
shared Emit per-domain code No1
sched Instruction scheduling No
intrins Intrinsic method implementations Yes
tailc Tail recursion and tailcalls No
loop Loop related optimizations Yes
fcmov Fast x86 FP compares No
leaf Leaf procedures and optimizations No
aot Usage of Ahead Of Time compiled code Yes
precomp Precompile all methods before executing No1
abcrem Array bound checks removal No
ssapre SSA based Partial Redundancy No
exception Optimize exception catch blocks Yes
ssa Use plain SSA form No
float32 Use 32 bit float arithmetic if possible No2
sse2 SSE2 instructions on x86 No
gsharedvt Generic sharing for valuetypes No1
gshared Generic Sharing Yes
simd Simd intrinsics Yes
unsafe Remove bound checks and perform other dangerous changes No1
alias-analysis Alias analysis of locals Yes
aggressive-inlining Aggressive Inlining No

1 These optimizations are not enabled by all and must be specified manually.

2 Enabled by default in Mono, disabled by default in Unity.