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* [X86] Add new calling convention that guarantees tail call optimizationReid Kleckner2019-10-071-0/+1
| | | | | | | | | | | | | | | | | When the target option GuaranteedTailCallOpt is specified, calls with the fastcc calling convention will be transformed into tail calls if they are in tail position. This diff adds a new calling convention, tailcc, currently supported only on X86, which behaves the same way as fastcc, except that the GuaranteedTailCallOpt flag does not need to enabled in order to enable tail call optimization. Patch by Dwight Guth <dwight.guth@runtimeverification.com>! Reviewed By: lebedev.ri, paquette, rnk Differential Revision: https://reviews.llvm.org/D67855 llvm-svn: 373976
* ARM MTE stack sanitizer.Evgeniy Stepanov2019-07-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Add "memtag" sanitizer that detects and mitigates stack memory issues using armv8.5 Memory Tagging Extension. It is similar in principle to HWASan, which is a software implementation of the same idea, but there are enough differencies to warrant a new sanitizer type IMHO. It is also expected to have very different performance properties. The new sanitizer does not have a runtime library (it may grow one later, along with a "debugging" mode). Similar to SafeStack and StackProtector, the instrumentation pass (in a follow up change) will be inserted in all cases, but will only affect functions marked with the new sanitize_memtag attribute. Reviewers: pcc, hctim, vitalybuka, ostannard Subscribers: srhines, mehdi_amini, javed.absar, kristof.beyls, hiraditya, cryptoad, steven_wu, dexonsmith, cfe-commits, llvm-commits Tags: #clang, #llvm Differential Revision: https://reviews.llvm.org/D64169 llvm-svn: 366123
* Add the ShadowCallStack attributeVlad Tsyrklevich2018-04-031-0/+1
| | | | | | | | | | | | | | | | | | Summary: Introduce the ShadowCallStack function attribute. It's added to functions compiled with -fsanitize=shadow-call-stack in order to mark functions to be instrumented by a ShadowCallStack pass to be submitted in a separate change. Reviewers: pcc, kcc, kubamracek Reviewed By: pcc, kcc Subscribers: cryptoad, mehdi_amini, javed.absar, llvm-commits, kcc Differential Revision: https://reviews.llvm.org/D44800 llvm-svn: 329108
* Document optforfuzzing attribute created in r328214.Matt Morehouse2018-03-221-0/+1
| | | | llvm-svn: 328236
* [X86] Added support for nocf_check attribute for indirect Branch TrackingOren Ben Simhon2018-03-171-0/+1
| | | | | | | | | | | | | | | X86 Supports Indirect Branch Tracking (IBT) as part of Control-Flow Enforcement Technology (CET). IBT instruments ENDBR instructions used to specify valid targets of indirect call / jmp. The `nocf_check` attribute has two roles in the context of X86 IBT technology: 1. Appertains to a function - do not add ENDBR instruction at the beginning of the function. 2. Appertains to a function pointer - do not track the target function of this pointer by adding nocf_check prefix to the indirect-call instruction. This patch implements `nocf_check` context for Indirect Branch Tracking. It also auto generates `nocf_check` prefixes before indirect branchs to jump tables that are guarded by range checks. Differential Revision: https://reviews.llvm.org/D41879 llvm-svn: 327767
* [NFC] fix trivial typos in documentsHiroshi Inoue2018-01-161-1/+1
| | | | | | "the the" -> "the" llvm-svn: 322552
* [docs] Only LLVM IR bitstreams begin with 'BC'Brian Gesiak2018-01-151-8/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: The LLVM Bitcode File Format documentation states that all bitstreams begin with the magic number 'BC', and that generic bitstream analyzer tools may check for this number in order to determine whether the stream is a bitstream. However, in practice: * Only LLVM IR bitcode begins with 'BC'. Other bitstreams -- Clang AST files and precompiled headers, Clang serialized diagnostics, Swift modules -- do not start with 'BC'. A tool that actually checked for 'BC' would only be able to recognize LLVM IR. * The `llvm-bcanalyzer`, arguably the most used generic bitstream analyzer tool, does not check for a magic number 'BC' (except to determine whether the file is LLVM IR). Update the bitcode format documentation to make it clear that not all bitstreams begin with 'BC', and that tools should not rely on that particular magic number value. Test Plan: Build the `docs-llvm-html` target and confirm the changes render in a Safari web browser. Reviewers: harlanhaskins, eugenis, mehdi_amini, pcc, angerman Reviewed By: angerman Subscribers: angerman, llvm-commits Differential Revision: https://reviews.llvm.org/D42002 llvm-svn: 322520
* Hardware-assisted AddressSanitizer (llvm part).Evgeniy Stepanov2017-12-091-0/+1
| | | | | | | | | | | | | | | | | | | | | Summary: This is LLVM instrumentation for the new HWASan tool. It is basically a stripped down copy of ASan at this point, w/o stack or global support. Instrumenation adds a global constructor + runtime callbacks for every load and store. HWASan comes with its own IR attribute. A brief design document can be found in clang/docs/HardwareAssistedAddressSanitizerDesign.rst (submitted earlier). Reviewers: kcc, pcc, alekseyshl Subscribers: srhines, mehdi_amini, mgorny, javed.absar, eraman, llvm-commits, hiraditya Differential Revision: https://reviews.llvm.org/D40932 llvm-svn: 320217
* Update BitCodeFormat.Evgeniy Stepanov2017-12-071-0/+2
| | | | | | | Add 2 recently added attributes to list of well-known attributes in BitCodeFormat.rst. llvm-svn: 319999
* Represent runtime preemption in the IR.Sean Fertile2017-10-261-3/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we do not represent runtime preemption in the IR, which has several drawbacks: 1) The semantics of GlobalValues differ depending on the object file format you are targeting (as well as the relocation-model and -fPIE value). 2) We have no way of disabling inlining of run time interposable functions, since in the IR we only know if a function is link-time interposable. Because of this llvm cannot support elf-interposition semantics. 3) In LTO builds of executables we will have extra knowledge that a symbol resolved to a local definition and can't be preemptable, but have no way to propagate that knowledge through the compiler. This patch adds preemptability specifiers to the IR with the following meaning: dso_local --> means the compiler may assume the symbol will resolve to a definition within the current linkage unit and the symbol may be accessed directly even if the definition is not within this compilation unit. dso_preemptable --> means that the compiler must assume the GlobalValue may be replaced with a definition from outside the current linkage unit at runtime. To ease transitioning dso_preemptable is treated as a 'default' in that low-level codegen will still do the same checks it did previously to see if a symbol should be accessed indirectly. Eventually when IR producers emit the specifiers on all Globalvalues we can change dso_preemptable to mean 'always access indirectly', and remove the current logic. Differential Revision: https://reviews.llvm.org/D20217 llvm-svn: 316668
* Bitcode: Add a string table to the bitcode format.Peter Collingbourne2017-04-171-4/+38
| | | | | | | | | | | | | | | | | | | | | | | Add a top-level STRTAB block containing a string table blob, and start storing strings for module codes FUNCTION, GLOBALVAR, ALIAS, IFUNC and COMDAT in the string table. This change allows us to share names between globals and comdats as well as between modules, and improves the efficiency of loading bitcode files by no longer using a bit encoding for symbol names. Once we start writing the irsymtab to the bitcode file we will also be able to share strings between it and the module. On my machine, link time for Chromium for Linux with ThinLTO decreases by about 7% for no-op incremental builds or about 1% for full builds. Total bitcode file size decreases by about 3%. As discussed on llvm-dev: http://lists.llvm.org/pipermail/llvm-dev/2017-April/111732.html Differential Revision: https://reviews.llvm.org/D31838 llvm-svn: 300464
* Bitcode: Remove reader support for MODULE_CODE_PURGEVALS.Peter Collingbourne2017-04-031-10/+0
| | | | | | | | | | Support for writing this module code was removed in r73220, which was well before the LLVM 3.0 release, so we do not need to be able to understand it for backwards compatibility. Differential Revision: https://reviews.llvm.org/D31563 llvm-svn: 299370
* [docs] Update some obsolete information in BitCodeFormat docs.Mehdi Amini2016-10-141-45/+201
| | | | | | | | | | | | | | | | Summary: * Describe new (3.3) parameter attribute group encoding, leaving old encoding there with a note about legacy * Bring TYPE_BLOCK docs up to date * Remove docs about obsolete (pre 3.0) TYPE_SYMTAB_BLOCK, TST_CODE_ENTRY * Fix a couple of incorrect comments and remove one unused enum definition along the way This addresses https://llvm.org/bugs/show_bug.cgi?id=28941. Patch by: Ismail Badawi <ibadawi@cisco.com> Differential Revision: https://reviews.llvm.org/D25623 llvm-svn: 284246
* This code block breaks the docs build ↵Aaron Ballman2016-07-191-2/+2
| | | | | | (http://lab.llvm.org:8011/builders/llvm-sphinx-docs/builds/11921/steps/docs-llvm-html/logs/stdio). Setting the code highlighting to none instead of llvm to hopefully get the bot stumbling back towards green. llvm-svn: 276018
* IR: Allow metadata attachments on declarations, and fix lazy loaded metadata ↵Peter Collingbourne2016-06-211-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | issue with globals. This change is motivated by an upcoming change to the metadata representation used for CFI. The indirect function call checker needs type information for external function declarations in order to correctly generate jump table entries for such declarations. We currently associate such type information with declarations using a global metadata node, but I plan [1] to move all such metadata to global object attachments. In bitcode, metadata attachments for function declarations appear in the global metadata block. This seems reasonable to me because I expect metadata attachments on declarations to be uncommon. In the long term I'd also expect this to be the case for CFI, because we'd want to use some specialized bitcode format for this metadata that could be read as part of the ThinLTO thin-link phase, which would mean that it would not appear in the global metadata block. To solve the lazy loaded metadata issue I was seeing with D20147, I use the same bitcode representation for metadata attachments for global variables as I do for function declarations. Since there's a use case for metadata attachments in the global metadata block, we might as well use that representation for global variables as well, at least until we have a mechanism for lazy loading global variables. In the assembly format, the metadata attachments appear after the "declare" keyword in order to avoid a parsing ambiguity. [1] http://lists.llvm.org/pipermail/llvm-dev/2016-June/100462.html Differential Revision: http://reviews.llvm.org/D21052 llvm-svn: 273336
* IR: Introduce local_unnamed_addr attribute.Peter Collingbourne2016-06-141-6/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a local_unnamed_addr attribute is attached to a global, the address is known to be insignificant within the module. It is distinct from the existing unnamed_addr attribute in that it only describes a local property of the module rather than a global property of the symbol. This attribute is intended to be used by the code generator and LTO to allow the linker to decide whether the global needs to be in the symbol table. It is possible to exclude a global from the symbol table if three things are true: - This attribute is present on every instance of the global (which means that the normal rule that the global must have a unique address can be broken without being observable by the program by performing comparisons against the global's address) - The global has linkonce_odr linkage (which means that each linkage unit must have its own copy of the global if it requires one, and the copy in each linkage unit must be the same) - It is a constant or a function (which means that the program cannot observe that the unique-address rule has been broken by writing to the global) Although this attribute could in principle be computed from the module contents, LTO clients (i.e. linkers) will normally need to be able to compute this property as part of symbol resolution, and it would be inefficient to materialize every module just to compute it. See: http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160509/356401.html http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160516/356738.html for earlier discussion. Part of the fix for PR27553. Differential Revision: http://reviews.llvm.org/D20348 llvm-svn: 272709
* Add support for metadata attachments for global variables.Peter Collingbourne2016-05-311-0/+10
| | | | | | | | | | This patch adds an IR, assembly and bitcode representation for metadata attachments for globals. Future patches will port existing features to use these new attachments. Differential Revision: http://reviews.llvm.org/D20074 llvm-svn: 271348
* docs: Update and clean up BitCodeFormat.rst.Peter Collingbourne2016-05-171-1/+14
| | | | llvm-svn: 269857
* Swift Calling Convention: add swiftcc.Manman Ren2016-04-051-0/+1
| | | | | | Differential Revision: http://reviews.llvm.org/D17863 llvm-svn: 265480
* Rename embedded bitcode section in MachOSteven Wu2016-02-291-4/+5
| | | | | | | | | | | | | | Summary: Rename the section embeds bitcode from ".llvmbc,.llvmbc" to "__LLVM,__bitcode". The new name matches MachO section naming convention. Reviewers: rafael, pcc Subscribers: davide, llvm-commits, joker.eph Differential Revision: http://reviews.llvm.org/D17388 llvm-svn: 262245
* [CXX TLS calling convention] Add CXX TLS calling convention.Manman Ren2015-12-041-0/+1
| | | | | | | | | | | | | | | | | | | | | This commit adds a new target-independent calling convention for C++ TLS access functions. It aims to minimize overhead in the caller by perserving as many registers as possible. The target-specific implementation for X86-64 is defined as following: Arguments are passed as for the default C calling convention The same applies for the return value(s) The callee preserves all GPRs - except RAX and RDI The access function makes C-style TLS function calls in the entry and exit block, C-style TLS functions save a lot more registers than normal calls. The added calling convention ties into the existing implementation of the C-style TLS functions, so we can't simply use existing calling conventions such as preserve_mostcc. rdar://9001553 llvm-svn: 254737
* Fix typos.Bruce Mitchener2015-09-121-2/+2
| | | | | | | | | | Summary: This fixes a variety of typos in docs, code and headers. Subscribers: jholewinski, sanjoy, arsenm, llvm-commits Differential Revision: http://reviews.llvm.org/D12626 llvm-svn: 247495
* Move the personality function from LandingPadInst to FunctionDavid Majnemer2015-06-171-1/+3
| | | | | | | | | | | | | | | | | | | The personality routine currently lives in the LandingPadInst. This isn't desirable because: - All LandingPadInsts in the same function must have the same personality routine. This means that each LandingPadInst beyond the first has an operand which produces no additional information. - There is ongoing work to introduce EH IR constructs other than LandingPadInst. Moving the personality routine off of any one particular Instruction and onto the parent function seems a lot better than have N different places a personality function can sneak onto an exceptional function. Differential Revision: http://reviews.llvm.org/D10429 llvm-svn: 239940
* Misc documentation/comment fixes.Peter Collingbourne2015-02-041-1/+1
| | | | llvm-svn: 228093
* Prologue supportPeter Collingbourne2014-12-031-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch by Ben Gamari! This redefines the `prefix` attribute introduced previously and introduces a `prologue` attribute. There are a two primary usecases that these attributes aim to serve, 1. Function prologue sigils 2. Function hot-patching: Enable the user to insert `nop` operations at the beginning of the function which can later be safely replaced with a call to some instrumentation facility 3. Runtime metadata: Allow a compiler to insert data for use by the runtime during execution. GHC is one example of a compiler that needs this functionality for its tables-next-to-code functionality. Previously `prefix` served cases (1) and (2) quite well by allowing the user to introduce arbitrary data at the entrypoint but before the function body. Case (3), however, was poorly handled by this approach as it required that prefix data was valid executable code. Here we redefine the notion of prefix data to instead be data which occurs immediately before the function entrypoint (i.e. the symbol address). Since prefix data now occurs before the function entrypoint, there is no need for the data to be valid code. The previous notion of prefix data now goes under the name "prologue data" to emphasize its duality with the function epilogue. The intention here is to handle cases (1) and (2) with prologue data and case (3) with prefix data. References ---------- This idea arose out of discussions[1] with Reid Kleckner in response to a proposal to introduce the notion of symbol offsets to enable handling of case (3). [1] http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-May/073235.html Test Plan: testsuite Differential Revision: http://reviews.llvm.org/D6454 llvm-svn: 223189
* Fix sphinx warning.Peter Collingbourne2014-09-181-3/+5
| | | | llvm-svn: 218081
* LTO: introduce object file-based on-disk module format.Peter Collingbourne2014-09-181-2/+16
| | | | | | | | | | | | | | | | | | This format is simply a regular object file with the bitcode stored in a section named ".llvmbc", plus any number of other (non-allocated) sections. One immediate use case for this is to accommodate compilation processes which expect the object file to contain metadata in non-allocated sections, such as the ".go_export" section used by some Go compilers [1], although I imagine that in the future we could consider compiling parts of the module (such as large non-inlinable functions) directly into the object file to improve LTO efficiency. [1] http://golang.org/doc/install/gccgo#Imports Differential Revision: http://reviews.llvm.org/D4371 llvm-svn: 218078
* Revert "[ms-cxxabi] Add a new calling convention that swaps 'this' and 'sret'"Reid Kleckner2014-05-091-2/+0
| | | | | | | | | | | | | | This reverts commit r200561. This calling convention was an attempt to match the MSVC C++ ABI for methods that return structures by value. This solution didn't scale, because it would have required splitting every CC available on Windows into two: one for methods and one for free functions. Now that we can put sret on the second arg (r208453), and Clang does that (r208458), revert this hack. llvm-svn: 208459
* Remove the linker_private and linker_private_weak linkages.Rafael Espindola2014-03-131-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These linkages were introduced some time ago, but it was never very clear what exactly their semantics were or what they should be used for. Some investigation found these uses: * utf-16 strings in clang. * non-unnamed_addr strings produced by the sanitizers. It turns out they were just working around a more fundamental problem. For some sections a MachO linker needs a symbol in order to split the section into atoms, and llvm had no idea that was the case. I fixed that in r201700 and it is now safe to use the private linkage. When the object ends up in a section that requires symbols, llvm will use a 'l' prefix instead of a 'L' prefix and things just work. With that, these linkages were already dead, but there was a potential future user in the objc metadata information. I am still looking at CGObjcMac.cpp, but at this point I am convinced that linker_private and linker_private_weak are not what they need. The objc uses are currently split in * Regular symbols (no '\01' prefix). LLVM already directly provides whatever semantics they need. * Uses of a private name (start with "\01L" or "\01l") and private linkage. We can drop the "\01L" and "\01l" prefixes as soon as llvm agrees with clang on L being ok or not for a given section. I have two patches in code review for this. * Uses of private name and weak linkage. The last case is the one that one could think would fit one of these linkages. That is not the case. The semantics are * the linker will merge these symbol by *name*. * the linker will hide them in the final DSO. Given that the merging is done by name, any of the private (or internal) linkages would be a bad match. They allow llvm to rename the symbols, and that is really not what we want. From the llvm point of view, these objects should really be (linkonce|weak)(_odr)?. For now, just keeping the "\01l" prefix is probably the best for these symbols. If we one day want to have a more direct support in llvm, IMHO what we should add is not a linkage, it is just a hidden_symbol attribute. It would be applicable to multiple linkages. For example, on weak it would produce the current behavior we have for objc metadata. On internal, it would be equivalent to private (and we should then remove private). llvm-svn: 203866
* Test commit - remove trailing whitespaceStephan Tolksdorf2014-03-131-1/+1
| | | | llvm-svn: 203834
* [ms-cxxabi] Add a new calling convention that swaps 'this' and 'sret'Reid Kleckner2014-01-311-0/+2
| | | | | | | | | | | | | | | | | | | | MSVC always places the 'this' parameter for a method first. The implicit 'sret' pointer for methods always comes second. We already implement this for __thiscall by putting sret parameters on the stack, but __cdecl methods require putting both parameters on the stack in opposite order. Using a special calling convention allows frontends to keep the sret parameter first, which avoids breaking lots of assumptions in LLVM and Clang. Fixes PR15768 with the corresponding change in Clang. Reviewers: ributzka, majnemer Differential Revision: http://llvm-reviews.chandlerc.com/D2663 llvm-svn: 200561
* Add two new calling conventions for runtime callsJuergen Ributzka2014-01-171-0/+2
| | | | | | | | | | | | | | This patch adds two new target-independent calling conventions for runtime calls - PreserveMost and PreserveAll. The target-specific implementation for X86-64 is defined as following: - Arguments are passed as for the default C calling convention - The same applies for the return value(s) - PreserveMost preserves all GPRs - except R11 - PreserveAll preserves all GPRs and all XMMs/YMMs - except R11 Reviewed by Lang and Philip llvm-svn: 199508
* Decouple dllexport/dllimport from linkageNico Rieck2014-01-141-3/+15
| | | | | | | | | | | | | | | | | | | Representing dllexport/dllimport as distinct linkage types prevents using these attributes on templates and inline functions. Instead of introducing further mixed linkage types to include linkonce and weak ODR, the old import/export linkage types are replaced with a new separate visibility-like specifier: define available_externally dllimport void @f() {} @Var = dllexport global i32 1, align 4 Linkage for dllexported globals and functions is now equal to their linkage without dllexport. Imported globals and functions must be either declarations with external linkage, or definitions with AvailableExternallyLinkage. llvm-svn: 199218
* Revert "Decouple dllexport/dllimport from linkage"Nico Rieck2014-01-141-15/+3
| | | | | | | | Revert this for now until I fix an issue in Clang with it. This reverts commit r199204. llvm-svn: 199207
* Decouple dllexport/dllimport from linkageNico Rieck2014-01-141-3/+15
| | | | | | | | | | | | | | | | | | | Representing dllexport/dllimport as distinct linkage types prevents using these attributes on templates and inline functions. Instead of introducing further mixed linkage types to include linkonce and weak ODR, the old import/export linkage types are replaced with a new separate visibility-like specifier: define available_externally dllimport void @f() {} @Var = dllexport global i32 1, align 4 Linkage for dllexported globals and functions is now equal to their linkage without dllexport. Imported globals and functions must be either declarations with external linkage, or definitions with AvailableExternallyLinkage. llvm-svn: 199204
* [anyregcc] Fix callee-save mask for anyregccJuergen Ributzka2014-01-111-0/+2
| | | | | | | Use separate callee-save masks for XMM and YMM registers for anyregcc on X86 and select the proper mask depending on the target cpu we compile for. llvm-svn: 198985
* Implement function prefix data as an IR feature.Peter Collingbourne2013-09-161-1/+4
| | | | | | | | | Previous discussion: http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-July/063909.html Differential Revision: http://llvm-reviews.chandlerc.com/D1191 llvm-svn: 190773
* docs: Fix long standing linking antipattern.Sean Silva2013-01-111-2/+0
| | | | | | | | | Before we learned about :doc:, we used :ref: and put a dummy link at the top of each page. Don't do that anymore. This fixes PR14891 as a special case. llvm-svn: 172162
* Better 80cols... *sigh*Joe Abbey2012-11-201-3/+3
| | | | llvm-svn: 168373
* Fixing a broken link.Joe Abbey2012-11-201-3/+3
| | | | llvm-svn: 168372
* Fix a typo in bitcode docs, from 165814.Jan Wen Voung2012-10-151-1/+1
| | | | llvm-svn: 165944
* Add bitcode instruction encoding documentation for module versionJan Wen Voung2012-10-121-1/+48
| | | | | | 0 and 1. Followup to 165739. llvm-svn: 165814
* Sphinxify the bitcode format document.Bill Wendling2012-06-281-0/+1045
llvm-svn: 159340
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