chakra-core/ChakraCore

Wrong Assertion in GlobOpt::CollectMemOpInfo

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#6,476 创建于 2020年7月1日

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 (3 评论) (1 反应) (0 负责人)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

贡献者指南

技术栈
cpp
领域
backend
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-3 hours
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
fresh
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
C++ knowledgeunderstanding of JIT compiler optimizations
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
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.