llvm-project

History

Nick Desaulniers b7926ce6d7 [IR] add fn attr for no_stack_protector; prevent inlining on mismatch 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		2020-10-23 11:55:39 -07:00
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all_backends	Update the file headers across all of the LLVM projects in the monorepo	2019-01-19 08:50:56 +00:00
analysis	Update the file headers across all of the LLVM projects in the monorepo	2019-01-19 08:50:56 +00:00
backends	Update the file headers across all of the LLVM projects in the monorepo	2019-01-19 08:50:56 +00:00
bitreader	Update the file headers across all of the LLVM projects in the monorepo	2019-01-19 08:50:56 +00:00
bitwriter	Update the file headers across all of the LLVM projects in the monorepo	2019-01-19 08:50:56 +00:00
executionengine	Update the file headers across all of the LLVM projects in the monorepo	2019-01-19 08:50:56 +00:00
irreader	Update the file headers across all of the LLVM projects in the monorepo	2019-01-19 08:50:56 +00:00
linker	Update the file headers across all of the LLVM projects in the monorepo	2019-01-19 08:50:56 +00:00
llvm	[IR] add fn attr for no_stack_protector; prevent inlining on mismatch	2020-10-23 11:55:39 -07:00
target	Update the file headers across all of the LLVM projects in the monorepo	2019-01-19 08:50:56 +00:00
transforms	[OCaml] Remove add_constant_propagation	2020-08-27 09:30:21 -07:00
CMakeLists.txt	…
README.txt	…

README.txt

This directory contains LLVM bindings for the OCaml programming language
(http://ocaml.org).

Prerequisites
-------------

* OCaml 4.00.0+.
* ctypes 0.4+.
* oUnit 2+ (only required for tests).
* CMake (to build LLVM).

Building the bindings
---------------------

If all dependencies are present, the bindings will be built and installed
as a part of the default CMake configuration, with no further action.
They will only work with the specific OCaml compiler detected during the build.

The bindings can also be built out-of-tree, i.e. targeting a preinstalled
LLVM. To do this, configure the LLVM build tree as follows:

    $ cmake -DLLVM_OCAML_OUT_OF_TREE=TRUE \
            -DCMAKE_INSTALL_PREFIX=[OCaml install prefix] \
            [... any other options]

then build and install it as:

    $ make ocaml_all
    $ cmake -P bindings/ocaml/cmake_install.cmake