{"record":{"id":"28b36025df4f7ad6","repo":"NationalSecurityAgency/ghidra","slug":"no-defining-p-code-op-for","errorCode":null,"errorMessage":"No defining p-code op for {}","messagePattern":"No defining p-code op for (.+?)","errorType":"exception","errorClass":"PcodeExecutionException","httpStatus":null,"severity":"error","filePath":"Ghidra/Debug/ProposedUtils/src/main/java/ghidra/pcode/eval/AbstractVarnodeEvaluator.java","lineNumber":218,"sourceCode":"\t\tfor (Varnode vn : storage.getVarnodes()) {\n\t\t\tT piece = evaluateVarnode(program, vn);\n\t\t\tvalue = catenate(total, value, piece, vn.getSize());\n\t\t}\n\t\treturn value;\n\t}\n\n\t/**\n\t * Evaluate the given varnode's defining p-code op\n\t * \n\t * @param program the program defining the static context\n\t * @param vn the varnode\n\t * @param already a cache of already-evaluated varnodes and their values\n\t * @return the value\n\t */\n\tprotected T evaluateBranch(Program program, Varnode vn, Map<Varnode, T> already) {\n\t\tPcodeOp def = vn.getDef();\n\t\tif (def == null || def.getOutput() != vn) {\n\t\t\tthrow new PcodeExecutionException(\"No defining p-code op for \" + vn);\n\t\t}\n\t\treturn evaluateOp(program, def, already);\n\t}\n\n\t/**\n\t * Evaluate a constant\n\t * \n\t * @param value the constant value\n\t * @param size the size of the value in bytes\n\t * @return the value\n\t */\n\tprotected abstract T evaluateConstant(long value, int size);\n\n\t/**\n\t * Evaluate the given register variable\n\t * \n\t * @param address the address of the register\n\t * @param size the size of the variable in bytes","sourceCodeStart":200,"sourceCodeEnd":236,"githubUrl":"https://github.com/NationalSecurityAgency/ghidra/blob/d5f144c24d6bc53c9cbf4448c6d11143e7696206/Ghidra/Debug/ProposedUtils/src/main/java/ghidra/pcode/eval/AbstractVarnodeEvaluator.java#L200-L236","documentation":"Thrown (unchecked PcodeExecutionException) by evaluateBranch when a varnode's defining p-code op is null (def == null) or when the op's output is not the varnode itself (def.getOutput() != vn). evaluateBranch assumes the varnode is the result of a p-code op; an undefined or already-consumed varnode violates that.","triggerScenarios":"Evaluating a varnode that is an instruction input/operand rather than an op output (def is null because it's a leaf/input), or a varnode whose defining op was rewritten so its output no longer matches. Also when the 'already' cache doesn't contain a leaf varnode and evaluation falls through to branch mode.","commonSituations":"Walking p-code and trying to evaluate a register/constant input varnode through evaluateBranch instead of treating it as a leaf; analyzing p-code after the op graph was mutated/cleared; a varnode reached before its defining op was evaluated.","solutions":["Route input/leaf varnodes through evaluateLeaf/evaluateVarnode (which checks the cache and handles constants) rather than evaluateBranch.","Ensure the defining op is evaluated first so the varnode is cached before you need its value.","Guard with vn.getDef() != null && vn.getDef().getOutput() == vn before calling evaluateBranch.","If the varnode is genuinely undefined, treat it as an unknown symbol rather than throwing."],"exampleFix":"// before\nT val = evaluator.evaluateBranch(program, vn, cache); // throws if vn is an input\n\n// after: only use evaluateBranch when vn is genuinely an op output\nPcodeOp def = vn.getDef();\nT val = (def != null && def.getOutput() == vn)\n    ? evaluator.evaluateBranch(program, vn, cache)\n    : evaluator.evaluateVarnode(program, vn, cache);","handlingStrategy":"validation","validationCode":"// Only evaluate via branch when vn is genuinely an op output\nPcodeOp def = vn.getDef();\nif (def == null || def.getOutput() != vn) {\n    // not an op output: use leaf evaluation instead\n}","typeGuard":null,"tryCatchPattern":"try {\n    T val = evaluator.evaluateBranch(program, vn, cache);\n} catch (PcodeExecutionException e) {\n    if (e.getMessage().startsWith(\"No defining p-code op\")) { /* evaluate as leaf instead */ }\n    else throw e;\n}","preventionTips":["Route input/leaf varnodes through evaluateVarnode, not evaluateBranch.","Evaluate defining ops first so results are cached.","Guard on vn.getDef() != null && vn.getDef().getOutput() == vn before branch evaluation."],"tags":["pcode","emulation","varnode","defining-op","unchecked-exception"],"backgroundTag":null,"analyzedSha":"d5f144c24d6bc53c9cbf4448c6d11143e7696206","analyzedAt":"2026-08-14T01:00:57.564Z","schemaVersion":2},"datasetVersion":"2026-08-14T05:17:29.042Z"}