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JVM opcode and ASM instruction coverage

Legend:

  • S — direct cppsnippets.properties expansion.
  • H+S — handler supplies operands/cache setup, then expands a snippet.
  • H — handler emits C++ directly or composes helper snippets.
  • P — bytecode preprocessor must lower it before code generation.
  • N — ASM normalizes this class-file encoding to another listed opcode/node.
  • U — unsupported: processing throws, or the class reader cannot supply a handled node.

The evidence chain is the handler registration table (MethodProcessor.java:55-79), generic snippet lookup (GenericInstructionHandler.java:19-61), concrete stack switches, and all snippet definitions (obfuscator/src/main/resources/sources/cppsnippets.properties:13-574).

Every JVM opcode

Value(s) Opcode(s) Status and implementation
0 nop S, NOP.
1 aconst_null S.
2-8 iconst_m1, iconst_0, iconst_1, iconst_2, iconst_3, iconst_4, iconst_5 S.
9-10 lconst_0, lconst_1 S.
11-13 fconst_0, fconst_1, fconst_2 S.
14-15 dconst_0, dconst_1 S.
16-17 bipush, sipush H+S via IntHandler (IntHandler.java:10-32).
18 ldc H+S for String, int, float, long, double, and class Type; P for method Type and Handle; U for ConstantDynamic and every other constant kind (LdcHandler.java:40-89; LdcPreprocessor.java:10-39).
19-20 ldc_w, ldc2_w N to ASM LdcInsnNode/opcode LDC; same type-dependent result as 18.
21-25 iload, lload, fload, dload, aload H+S via VarHandler (VarHandler.java:10-38).
26-45 iload_0..3, lload_0..3, fload_0..3, dload_0..3, aload_0..3 N to 21-25 plus local index by ASM.
46-53 iaload, laload, faload, daload, aaload, baload, caload, saload S; JNI array access and explicit null/exception handling (cppsnippets.properties:42-73).
54-58 istore, lstore, fstore, dstore, astore H+S via VarHandler.
59-78 istore_0..3, lstore_0..3, fstore_0..3, dstore_0..3, astore_0..3 N to 54-58 plus local index by ASM.
79-86 iastore, lastore, fastore, dastore, aastore, bastore, castore, sastore S; JNI array access (cppsnippets.properties:79-110).
87-95 pop, pop2, dup, dup_x1, dup_x2, dup2, dup2_x1, dup2_x2, swap S; stack-pointer effects are enumerated in InsnHandler.java:19-136.
96-115 iadd, ladd, fadd, dadd, isub, lsub, fsub, dsub, imul, lmul, fmul, dmul, idiv, ldiv, fdiv, ddiv, irem, lrem, frem, drem S; integer zero/overflow cases are special snippets (cppsnippets.properties:120-151).
116-119 ineg, lneg, fneg, dneg S.
120-125 ishl, lshl, ishr, lshr, iushr, lushr S.
126-131 iand, land, ior, lor, ixor, lxor S.
132 iinc H+S via IincHandler (IincHandler.java:8-21).
133-147 i2l, i2f, i2d, l2i, l2f, l2d, f2i, f2l, f2d, d2i, d2l, d2f, i2b, i2c, i2s S.
148-152 lcmp, fcmpl, fcmpg, dcmpl, dcmpg S, including explicit NaN ordering (cppsnippets.properties:184-188).
153-158 ifeq, ifne, iflt, ifge, ifgt, ifle H+S via JumpHandler (JumpHandler.java:10-44).
159-166 if_icmpeq, if_icmpne, if_icmplt, if_icmpge, if_icmpgt, if_icmple, if_acmpeq, if_acmpne H+S; reference comparisons use IsSameObject.
167 goto H+S.
168 jsr U: JumpHandler has no case and no snippet; it throws (JumpHandler.java:21-44).
169 ret U: VarHandler has no case and no snippet; it throws (VarHandler.java:21-38).
170 tableswitch H, composed from four switch snippets (TableSwitchHandler.java:11-52; cppsnippets.properties:234-237).
171 lookupswitch H, composed from four switch snippets (LookupSwitchHandler.java:11-52; cppsnippets.properties:238-241).
172-177 ireturn, lreturn, freturn, dreturn, areturn, return S.
178-181 getstatic, putstatic, getfield, putfield H+S; specialized by field sort, with lazy class/field-ID setup (FieldHandler.java:14-65; cppsnippets.properties:248-360).
182-185 invokevirtual, invokespecial, invokestatic, invokeinterface H+S; specialized by return sort, with argument snippets and lazy class/method-ID setup (MethodHandler.java:151-224; cppsnippets.properties:395-565). Method-handle invocation and synthetic preprocessor calls are further H special cases (MethodHandler.java:32-149).
186 invokedynamic P. IndyPreprocessor replaces every node (IndyPreprocessor.java:374-381); reaching InvokeDynamicHandler throws on all methods (InvokeDynamicHandler.java:6-20).
187 new H+S via TypeHandler; uses AllocObject, while the following constructor call is invokespecial.
188 newarray H+S, selected by atype 4-11 (IntHandler.java:11-15; cppsnippets.properties:362-393).
189 anewarray H+S via TypeHandler.
190-191 arraylength, athrow S.
192-193 checkcast, instanceof H+S via TypeHandler.
194-195 monitorenter, monitorexit S.
196 wide N: ASM exposes the widened load/store/ret/iinc as the ordinary node. Widened supported operations work; widened ret remains U.
197 multianewarray H+S; primitive and reference paths use runtime recursive helpers (MultiANewArrayHandler.java:13-36; cppsnippets.properties:567-570; native_jvm.cpp:180-237; native_jvm.hpp:31-76). The source retains a // TODO, so coverage is implemented but not evidence of semantic completeness (MultiANewArrayHandler.java:26).
198-199 ifnull, ifnonnull H+S via JumpHandler.
200 goto_w N to ASM GOTO; supported as 167.
201 jsr_w N to ASM JSR, then U as 168.
202 breakpoint U; reserved for JVM implementation use and absent from handlers/snippets.
203-253 reserved U; not defined class-file instructions and absent from handlers/snippets.
254-255 impdep1, impdep2 U; reserved for JVM implementation use and absent from handlers/snippets.

ASM node-type map

AbstractInsnNode type Handler Result
INSN InsnHandler S for all accepted zero-operand opcodes.
INT_INSN IntHandler H+S: BIPUSH, SIPUSH, NEWARRAY.
VAR_INSN VarHandler H+S: typed loads/stores; RET is U.
TYPE_INSN TypeHandler H+S: NEW, ANEWARRAY, CHECKCAST, INSTANCEOF.
FIELD_INSN FieldHandler H+S, field-sort variants.
METHOD_INSN MethodHandler H+S, plus synthetic/method-handle H paths.
INVOKE_DYNAMIC_INSN InvokeDynamicHandler U if reached; required P path should remove it.
JUMP_INSN JumpHandler H+S except JSR U.
LABEL LabelHandler H: active-catch tracking and C++ label; deliberately bypasses snippet lookup (LabelHandler.java:9-35).
LDC_INSN LdcHandler Type-dependent H+S/P/U, as opcode 18.
IINC_INSN IincHandler H+S.
TABLESWITCH_INSN TableSwitchHandler H.
LOOKUPSWITCH_INSN LookupSwitchHandler H.
MULTIANEWARRAY_INSN MultiANewArrayHandler H+S.
FRAME FrameHandler H metadata: simulated types/reference cleanup, no JVM opcode (FrameHandler.java:17-116).
LINE LineNumberHandler H metadata: updates generated exception line, no JVM opcode (LineNumberHandler.java:7-19).

All 16 ASM node-type slots are registered. That does not imply all legal constant kinds or legacy subroutine opcodes are supported.