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* [X86] Add a Pass that builds a Condensed CFG for Load Value Injection (LVI) ↵Scott Constable2020-06-241-1/+7
| | | | | | | | | | | | | | Gadgets Adds a new data structure, ImmutableGraph, and uses RDF to find LVI gadgets and add them to a MachineGadgetGraph. More specifically, a new X86 machine pass finds Load Value Injection (LVI) gadgets consisting of a load from memory (i.e., SOURCE), and any operation that may transmit the value loaded from memory over a covert channel, or use the value loaded from memory to determine a branch/call target (i.e., SINK). Also adds a new target feature to X86: +lvi-load-hardening The feature can be added via the clang CLI using -mlvi-hardening. Differential Revision: https://reviews.llvm.org/D75936
* Revert "[X86] Add a Pass that builds a Condensed CFG for Load Value ↵Craig Topper2020-06-241-7/+1
| | | | | | | | | Injection (LVI) Gadgets" This reverts commit c74dd640fd740c6928f66a39c7c15a014af3f66f. Reverting to address coding standard issues raised in post-commit review.
* [X86] Add a Pass that builds a Condensed CFG for Load Value Injection (LVI) ↵Scott Constable2020-06-241-1/+7
| | | | | | | | | | | | | | Gadgets Adds a new data structure, ImmutableGraph, and uses RDF to find LVI gadgets and add them to a MachineGadgetGraph. More specifically, a new X86 machine pass finds Load Value Injection (LVI) gadgets consisting of a load from memory (i.e., SOURCE), and any operation that may transmit the value loaded from memory over a covert channel, or use the value loaded from memory to determine a branch/call target (i.e., SINK). Also adds a new target feature to X86: +lvi-load-hardening The feature can be added via the clang CLI using -mlvi-hardening. Differential Revision: https://reviews.llvm.org/D75936
* [X86] Add Indirect Thunk Support to X86 to mitigate Load Value Injection (LVI)Scott Constable2020-06-241-0/+17
| | | | | | | | | | | | | | | | | This pass replaces each indirect call/jump with a direct call to a thunk that looks like: lfence jmpq *%r11 This ensures that if the value in register %r11 was loaded from memory, then the value in %r11 is (architecturally) correct prior to the jump. Also adds a new target feature to X86: +lvi-cfi ("cfi" meaning control-flow integrity) The feature can be added via clang CLI using -mlvi-cfi. This is an alternate implementation to https://reviews.llvm.org/D75934 That merges the thunk insertion functionality with the existing X86 retpoline code. Differential Revision: https://reviews.llvm.org/D76812
* [NFC] Use isX86() instead of getArch()Jim Lin2020-01-071-2/+1
| | | | | | | | | | | | | | Summary: This is a clean up for https://reviews.llvm.org/D72247. Reviewers: MaskRay, craig.topper, jhenderson Reviewed By: MaskRay Subscribers: hiraditya, rupprecht, cfe-commits, llvm-commits Tags: #clang, #llvm Differential Revision: https://reviews.llvm.org/D72320
* Move endian constant from Host.h to SwapByteOrder.h, prune includeReid Kleckner2019-10-191-0/+1
| | | | | | | | | | | | | | Works on this dependency chain: ArrayRef.h -> Hashing.h -> --CUT-- Host.h -> StringMap.h / StringRef.h ArrayRef is very popular, but Host.h is rarely needed. Move the IsBigEndianHost constant to SwapByteOrder.h. Clients of that header are more likely to need it. llvm-svn: 375316
* Fix a typo in target featuresGeorge Burgess IV2019-07-161-1/+1
| | | | | | | | | There was a slight typo in r364352 that ended up causing our backend to complain on some x86 Android builds. This CL fixes that. Differential Revision: https://reviews.llvm.org/D64781 llvm-svn: 366276
* android: enable double-word CAS on x64Saleem Abdulrasool2019-06-251-0/+1
| | | | | | | | | | | The android target assumes that for the x86_64 target, the CPU supports SSE4.2 and popcnt. This implies that the CPU is Nehalem or newer. This should be sufficiently new to provide the double word compare and exchange instruction. This allows us to directly lower `__sync_val_compare_and_swap_16` to a `cmpxchg16b`. It appears that the libatomic in android's NDK does not provide the implementation for lowering calls to the library function. llvm-svn: 364352
* Update the file headers across all of the LLVM projects in the monorepoChandler Carruth2019-01-191-4/+3
| | | | | | | | | | | | | | | | | to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
* [Driver] Don't override '-march' when using '-arch x86_64h'Francis Visoiu Mistrih2018-12-171-5/+1
| | | | | | | | | | | | On Darwin, using '-arch x86_64h' would always override the option passed through '-march'. This patch allows users to use '-march' with x86_64h, while keeping the default to 'core-avx2' Differential Revision: https://reviews.llvm.org/D55775 llvm-svn: 349381
* [x86/SLH] Add a real Clang flag and LLVM IR attribute for SpeculativeChandler Carruth2018-09-041-5/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Load Hardening. Wires up the existing pass to work with a proper IR attribute rather than just a hidden/internal flag. The internal flag continues to work for now, but I'll likely remove it soon. Most of the churn here is adding the IR attribute. I talked about this Kristof Beyls and he seemed at least initially OK with this direction. The idea of using a full attribute here is that we *do* expect at least some forms of this for other architectures. There isn't anything *inherently* x86-specific about this technique, just that we only have an implementation for x86 at the moment. While we could potentially expose this as a Clang-level attribute as well, that seems like a good question to defer for the moment as it isn't 100% clear whether that or some other programmer interface (or both?) would be best. We'll defer the programmer interface side of this for now, but at least get to the point where the feature can be enabled without relying on implementation details. This also allows us to do something that was really hard before: we can enable *just* the indirect call retpolines when using SLH. For x86, we don't have any other way to mitigate indirect calls. Other architectures may take a different approach of course, and none of this is surfaced to user-level flags. Differential Revision: https://reviews.llvm.org/D51157 llvm-svn: 341363
* [x86/retpoline] Split the LLVM concept of retpolines into separateChandler Carruth2018-08-231-0/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | subtarget features for indirect calls and indirect branches. This is in preparation for enabling *only* the call retpolines when using speculative load hardening. I've continued to use subtarget features for now as they continue to seem the best fit given the lack of other retpoline like constructs so far. The LLVM side is pretty simple. I'd like to eventually get rid of the old feature, but not sure what backwards compatibility issues that will cause. This does remove the "implies" from requesting an external thunk. This always seemed somewhat questionable and is now clearly not desirable -- you specify a thunk the same way no matter which set of things are getting retpolines. I really want to keep this nicely isolated from end users and just an LLVM implementation detail, so I've moved the `-mretpoline` flag in Clang to no longer rely on a specific subtarget feature by that name and instead to be directly handled. In some ways this is simpler, but in order to preserve existing behavior I've had to add some fallback code so that users who relied on merely passing -mretpoline-external-thunk continue to get the same behavior. We should eventually remove this I suspect (we have never tested that it works!) but I've not done that in this patch. Differential Revision: https://reviews.llvm.org/D51150 llvm-svn: 340515
* [clang-cl] Add support for /arch:AVX512F and /arch:AVX512Nico Weber2018-01-251-5/+6
| | | | | | | | | | | | | | | | | | | | | For /arch:AVX512F: clang-cl and cl.exe both defines __AVX512F__ __AVX512CD__. clang-cl also defines __AVX512ER__ __AVX512PF__. 64-bit cl.exe also defines (according to /Bz) _NO_PREFETCHW. For /arch:AVX512: clang-cl and cl.exe both define __AVX512F__ __AVX512CD__ __AVX512BW__ __AVX512DQ__ __AVX512VL__. 64-bit cl.exe also defines _NO_PREFETCHW. So not 100% identical, but pretty close. Also refactor the existing AVX / AVX2 code to not repeat itself in both the 32-bit and 64-bit cases. https://reviews.llvm.org/D42538 llvm-svn: 323433
* clang-cl: Simplify handling of /arch: flag.Nico Weber2018-01-251-27/+5
| | | | | | | | | | | | | | | | | | | r213083 initially implemented /arch: support by mapping it to CPU features. Then r241077 additionally mapped it to CPU, which made the feature flags redundant (if harmless). This change here removes the redundant mapping to feature flags, and rewrites test/Driver/cl-x86-flags.c to be a bit more of an integration test that checks for preprocessor defines like AVX (like documented on MSDN) instead of for driver flags. To keep emitting warn_drv_unused_argument, use getLastArgNoClaim() followed by an explicit claim() if needed. This is in preparation for adding support for /arch:AVX512(F). No intended behavior change. https://reviews.llvm.org/D42497 llvm-svn: 323426
* Remove Bitrig: Clang ChangesErich Keane2017-07-211-2/+0
| | | | | | | | Bitrig code has been merged back to OpenBSD, thus the OS has been abandoned. Differential Revision: https://reviews.llvm.org/D35708 llvm-svn: 308797
* [X86] Remove some code that tries to disable HLE feature. This feature flag ↵Craig Topper2017-04-041-1/+0
| | | | | | was removed from the backend. llvm-svn: 299416
* [Driver] Consolidate tools and toolchains by target platform. (NFC)David L. Jones2017-03-081-0/+174
Summary: (This is a move-only refactoring patch. There are no functionality changes.) This patch splits apart the Clang driver's tool and toolchain implementation files. Each target platform toolchain is moved to its own file, along with the closest-related tools. Each target platform toolchain has separate headers and implementation files, so the hierarchy of classes is unchanged. There are some remaining shared free functions, mostly from Tools.cpp. Several of these move to their own architecture-specific files, similar to r296056. Some of them are only used by a single target platform; since the tools and toolchains are now together, some helpers now live in a platform-specific file. The balance are helpers related to manipulating argument lists, so they are now in a new file pair, CommonArgs.h and .cpp. I've tried to cluster the code logically, which is fairly straightforward for most of the target platforms and shared architectures. I think I've made reasonable choices for these, as well as the various shared helpers; but of course, I'm happy to hear feedback in the review. There are some particular things I don't like about this patch, but haven't been able to find a better overall solution. The first is the proliferation of files: there are several files that are tiny because the toolchain is not very different from its base (usually the Gnu tools/toolchain). I think this is mostly a reflection of the true complexity, though, so it may not be "fixable" in any reasonable sense. The second thing I don't like are the includes like "../Something.h". I've avoided this largely by clustering into the current file structure. However, a few of these includes remain, and in those cases it doesn't make sense to me to sink an existing file any deeper. Reviewers: rsmith, mehdi_amini, compnerd, rnk, javed.absar Subscribers: emaste, jfb, danalbert, srhines, dschuff, jyknight, nemanjai, nhaehnle, mgorny, cfe-commits Differential Revision: https://reviews.llvm.org/D30372 llvm-svn: 297250
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