llvm/llvm-project

crash when section has `.cfi_startproc` but no `.cfi_endproc`

已关闭

#177,852 创建于 2026年1月25日

在 GitHub 查看贡献者指南
 (7 条评论) (0 个反应) (1 位负责人)C++ (10,782 个派生)batch import
crashgood first issuellvm:mc

仓库指标

星标
 (26,378 个星标)
PR 合并指标
 (平均合并 1天 2小时) (30 天内合并 1,000 个 PR)

描述

LLVM crashes on this program

https://godbolt.org/z/9W51vc3bW

module asm ".pushsection .text.foo,\22ax\22, @progbits"
module asm ".type foo, @function"
module asm "foo:"
module asm ".cfi_startproc"
module asm ".popsection"

module asm ".type bar, @function"
module asm "bar:"
module asm ".cfi_startproc"
module asm ".cfi_endproc"

llc: /root/llvm-project/llvm/lib/MC/MCExpr.cpp:223: llvm::MCSymbolRefExpr::MCSymbolRefExpr(const llvm::MCSymbol*, llvm::MCExpr::Spec, const llvm::MCAsmInfo*, llvm::SMLoc): Assertion `Symbol' failed.

This assembly is malformed (but in a way that might come up during development). When the .popsection is removed, we actually get a nice error:

<inline asm>:8:1: error: starting new .cfi frame before finishing the previous one
.cfi_endproc
^
Compiler returned: 1

I think that .popsection should emit an error when the section opened a CFI scope that wasn't yet closed.

贡献者指南

研究方向
Investigate the assembly parsing code, likely in llvm/lib/MC/MCParser/AsmParser.cpp or MCStreamer.cpp, to understand how .cfi startproc and .cfi endproc directives are tracked. The issue suggests that .popsection should emit an error when a CFI scope is left open. Look for where section push/pop operations are handled and add a check for pending CFI frames before allowing a section pop. The existing error message 'starting new .cfi frame before finishing the previous one' indicates the tracking mechanism exists; extend it to .popsection.
技术栈
cpp
领域
tooling
议题类型
缺陷
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。
半天
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。
活跃
清晰度议题是否清楚说明期望改动、验收标准和下一步。
清晰
前置要求
understanding of CFI directivesfamiliarity with LLVM MC layer
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。
40