MokaIR is an intermediate representation of JVM bytecode in mokapot.
It is in a register-based, SSA form, and is designed to be easy to analyze.
Please checkout the module mokapot::ir for more information.
To generate MokaIR from a method, use the following code.
use mokapot::ir::{MokaIRMethod, MokaIRMethodExt};
fn moka_ir() -> Result<MokaIRMethod, Box<dyn std::error::Error>> {
let method: Method = todo!("Some method");
let moka_ir_method = method.brew()?;
Ok(moka_ir_method)
}The following is an example of the generated IR from the method test() in test_data/TestAnalysis.java.
You may notice that there are lots of nops in the generated MokaIR.
This because we indent to maintain a bijection between the original bytecode and the generated MokaIR.
Such a bijection facilitates the analysis involving dynamic execution - the runtime information (e.g., coverage) can be applied to MokaIR without needing any remapping.
#00000: ldc => %0 = String("233")
#00002: astore_3 => nop
#00003: iconst_2 => %3 = int(2)
#00004: istore => nop
#00006: iload_1 => nop
#00007: iload => nop
#00009: iadd => %9 = %3 + %arg0
#00010: istore => nop
#00012: iload_1 => nop
#00013: ifge => if %arg0 >= 0 goto #00019
#00016: iconst_3 => %16 = int(3)
#00017: istore => nop
#00019: aload_0 => nop
#00020: aload_3 => nop
#00021: iload => nop
#00023: iload_2 => nop
#00024: invokevirtual => %24 = call int %this@org/mokapot/test/TestAnalysis::callMe(%0, Phi(%3, %16), %arg1)
#00027: istore => nop
#00029: iload => nop
#00031: ireturn => return %24
#00032: astore_3 => nop
#00033: getstatic => %33 = read java/lang/System.out
#00036: aload_3 => nop
#00037: invokevirtual => %37 = call void %33@java/io/PrintStream::println(%caught_exception)
#00040: iconst_0 => %40 = int(0)
#00041: istore_3 => nop
#00042: iload_3 => nop
#00043: iload_2 => nop
#00044: if_icmpge => if %arg1 >= Phi(%40, %64) goto #00070
#00047: getstatic => %47 = read java/lang/System.out
#00050: ldc => %50 = String(0x61 0x02 0xED 0xA0 0x80 0x62 0x63 0x64 0x65 0x66) // Invalid UTF-8
#00052: invokevirtual => %52 = call void %47@java/io/PrintStream::println(%50)
#00055: aload_0 => nop
#00056: ldc => %56 = String("233")
#00058: iconst_0 => %58 = int(0)
#00059: iconst_0 => %59 = int(0)
#00060: invokevirtual => %60 = call int %this@org/mokapot/test/TestAnalysis::callMe(%56, %58, %59)
#00063: pop => nop
#00064: iinc => %64 = Phi(%40, %64) + 1
#00067: goto => goto #00042
#00070: iload_1 => nop
#00071: ifle => if %arg0 <= 0 goto #00081
#00074: iload_2 => nop
#00075: ifle => if %arg1 <= 0 goto #00087
#00078: goto => goto #00085
#00081: iload_2 => nop
#00082: ifge => if %arg1 >= 0 goto #00087
#00085: iconst_0 => %85 = int(0)
#00086: ireturn => return %85
#00087: iload_1 => nop
#00088: invokedynamic => %88 = closure java/util/function/IntUnaryOperator applyAsInt#0(%arg0)
#00093: astore_3 => nop
#00094: aload_3 => nop
#00095: iconst_0 => %95 = int(0)
#00096: invokeinterface => %96 = call int %88@java/util/function/IntUnaryOperator::applyAsInt(%95)
#00101: istore => nop
#00103: iconst_3 => %103 = int(3)
#00104: newarray => %104 = new I[%103]
#00106: dup => nop
#00107: iconst_0 => %107 = int(0)
#00108: iconst_0 => %108 = int(0)
#00109: iastore => %109 = %104[%107] = %108
#00110: dup => nop
#00111: iconst_1 => %111 = int(1)
#00112: iconst_1 => %112 = int(1)
#00113: iastore => %113 = %104[%111] = %112
#00114: dup => nop
#00115: iconst_2 => %115 = int(2)
#00116: iconst_2 => %116 = int(2)
#00117: iastore => %117 = %104[%115] = %116
#00118: astore => nop
#00120: aload => nop
#00122: iconst_0 => %122 = int(0)
#00123: iload_1 => nop
#00124: iadd => %124 = %arg0 + %122
#00125: iaload => %125 = %104[%124]
#00126: istore => nop
#00128: aload => nop
#00130: iload => nop
#00132: iload => nop
#00134: iastore => %134 = %104[%125] = %125
#00135: iload_2 => nop
#00136: ireturn => return %arg1