forked from OSchip/llvm-project
b7926ce6d7
It's currently ambiguous in IR whether the source language explicitly did not want a stack a stack protector (in C, via function attribute no_stack_protector) or doesn't care for any given function. It's common for code that manipulates the stack via inline assembly or that has to set up its own stack canary (such as the Linux kernel) would like to avoid stack protectors in certain functions. In this case, we've been bitten by numerous bugs where a callee with a stack protector is inlined into an __attribute__((__no_stack_protector__)) caller, which generally breaks the caller's assumptions about not having a stack protector. LTO exacerbates the issue. While developers can avoid this by putting all no_stack_protector functions in one translation unit together and compiling those with -fno-stack-protector, it's generally not very ergonomic or as ergonomic as a function attribute, and still doesn't work for LTO. See also: https://lore.kernel.org/linux-pm/20200915172658.1432732-1-rkir@google.com/ https://lore.kernel.org/lkml/20200918201436.2932360-30-samitolvanen@google.com/T/#u Typically, when inlining a callee into a caller, the caller will be upgraded in its level of stack protection (see adjustCallerSSPLevel()). By adding an explicit attribute in the IR when the function attribute is used in the source language, we can now identify such cases and prevent inlining. Block inlining when the callee and caller differ in the case that one contains `nossp` when the other has `ssp`, `sspstrong`, or `sspreq`. Fixes pr/47479. Reviewed By: void Differential Revision: https://reviews.llvm.org/D87956 |
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README
-*- llvm/utils/vim/README -*-
This directory contains settings for the vim editor to work on llvm *.ll and
tablegen *.td files. It comes with filetype detection rules in the (ftdetect),
syntax highlighting (syntax), some minimal sensible default settings (ftplugin)
and indentation plugins (indent).
To install copy all subdirectories to your $HOME/.vim or if you prefer create
symlinks to the files here. Do not copy the vimrc file here it is only meant as
an inspiration and starting point for those working on llvm c++ code.
Note: If you notice missing or incorrect syntax highlighting, please contact
<llvm-bugs [at] lists.llvm.org>; if you wish to provide a patch to improve the
functionality, it will be most appreciated. Thank you.
If you find yourself working with LLVM Makefiles often, but you don't get syntax
highlighting (because the files have names such as Makefile.rules or
TEST.nightly.Makefile), add the following to your ~/.vimrc:
" LLVM Makefile highlighting mode
augroup filetype
au! BufRead,BufNewFile *Makefile* set filetype=make
augroup END