chakra-core/ChakraCore

Wrong Assertion in GlobOpt::CollectMemOpInfo

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#6,476 建立於 2020年7月1日

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 (3 留言) (1 反應) (0 負責人)JavaScript (9,000 star) (1,374 fork)batch import
BugLinuxgood first issue

描述

Hello, running following code in ch 1.11.19 debug version. An Assertion will be throw.

'use strict';
function func(b, c) {
    b[0] = c;
}
function main() {
    let b = new Uint32Array(100);

    for (let i = 0; i < 1000; i++) {
        i += 1;
        i += 0;
        func(b, {});
    }
}
main();

Output:

ASSERTION 19136: (...\chakracore-1.11.19\lib\backend\globopt.cpp, line 2325) !instr->GetDst() || instr->m_opcode == Js::OpCode::IncrLoopBodyCount || !loop->memOpInfo || (instr->m_opcode == Js::OpCode::Ld_I4 && prevInstr && (prevInstr->m_opcode == Js::OpCode::Add_I4 || prevInstr->m_opcode == Js::OpCode::Sub_I4) && instr->GetSrc1()->IsRegOpnd() && instr->GetDst()->IsRegOpnd() && prevInstr->GetDst()->IsRegOpnd() && instr->GetDst()->GetStackSym() == prevInstr->GetSrc1()->GetStackSym() && instr->GetSrc1()->GetStackSym() == prevInstr->GetDst()->GetStackSym()) || !loop->memOpInfo->inductionVariableChangeInfoMap->ContainsKey(GetVarSymID(instr->GetDst()->GetStackSym()))
 Failure: (!instr->GetDst() || instr->m_opcode == Js::OpCode::IncrLoopBodyCount || !loop->memOpInfo || (instr->m_opcode == Js::OpCode::Ld_I4 && prevInstr && (prevInstr->m_opcode == Js::OpCode::Add_I4 || prevInstr->m_opcode == Js::OpCode::Sub_I4) && instr->GetSrc1()->IsRegOpnd() && instr->GetDst()->IsRegOpnd() && prevInstr->GetDst()->IsRegOpnd() && instr->GetDst()->GetStackSym() == prevInstr->GetSrc1()->GetStackSym() && instr->GetSrc1()->GetStackSym() == prevInstr->GetDst()->GetStackSym()) || !loop->memOpInfo->inductionVariableChangeInfoMap->ContainsKey(GetVarSymID(instr->GetDst()->GetStackSym())))
FATAL ERROR: ch.exe failed due to exception code c0000420

I think this is likely just a wrong assertion since the assumption strict too much, may miss some cases. https://github.com/microsoft/ChakraCore/blob/33db8efd9f02cd528a7305391d7d10765a2e85f3/lib/Backend/GlobOpt.cpp#L2360-2374

ISec Lab 2020.7.1

貢獻者指南

技術棧
cpp
領域
backend
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
1-3 hours
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
fresh
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
C++ knowledgeunderstanding of JIT compiler optimizations
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
20
研究方向
Reproduce the assertion failure using the provided JavaScript code in ChakraCore debug build. Examine the assertion at GlobOpt.cpp line 2360-2374 to understand the assumed invariant. The issue suggests the assertion is too strict; consider removing or relaxing the condition to handle cases where the induction variable change info map does not contain the expected key. Verify the fix by running the test case and ensuring no regression.