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* Remove redundant includes from lib/Bitcode.Michael Zolotukhin2017-12-132-5/+0
| | | | llvm-svn: 320618
* Hardware-assisted AddressSanitizer (llvm part).Evgeniy Stepanov2017-12-091-0/+3
| | | | | | | | | | | | | | | | | | | | | 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
* [WebAssembly] Explicily disable comdat support for wasm outputSam Clegg2017-11-141-3/+3
| | | | | | | | | | | | | For now at least. We clearly need some kind of comdat or linkonce_odr support for wasm but currently COMDAT is not supported. Disable COMDAT support in the same way we do the Mach-O. This also causes clang not to generated COMDATs. Differential Revision: https://reviews.llvm.org/D39873 llvm-svn: 318123
* [IR] redefine 'UnsafeAlgebra' / 'reassoc' fast-math-flags and add 'trans' ↵Sanjay Patel2017-11-061-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fast-math-flag As discussed on llvm-dev: http://lists.llvm.org/pipermail/llvm-dev/2016-November/107104.html and again more recently: http://lists.llvm.org/pipermail/llvm-dev/2017-October/118118.html ...this is a step in cleaning up our fast-math-flags implementation in IR to better match the capabilities of both clang's user-visible flags and the backend's flags for SDNode. As proposed in the above threads, we're replacing the 'UnsafeAlgebra' bit (which had the 'umbrella' meaning that all flags are set) with a new bit that only applies to algebraic reassociation - 'AllowReassoc'. We're also adding a bit to allow approximations for library functions called 'ApproxFunc' (this was initially proposed as 'libm' or similar). ...and we're out of bits. 7 bits ought to be enough for anyone, right? :) FWIW, I did look at getting this out of SubclassOptionalData via SubclassData (spacious 16-bits), but that's apparently already used for other purposes. Also, I don't think we can just add a field to FPMathOperator because Operator is not intended to be instantiated. We'll defer movement of FMF to another day. We keep the 'fast' keyword. I thought about removing that, but seeing IR like this: %f.fast = fadd reassoc nnan ninf nsz arcp contract afn float %op1, %op2 ...made me think we want to keep the shortcut synonym. Finally, this change is binary incompatible with existing IR as seen in the compatibility tests. This statement: "Newer releases can ignore features from older releases, but they cannot miscompile them. For example, if nsw is ever replaced with something else, dropping it would be a valid way to upgrade the IR." ( http://llvm.org/docs/DeveloperPolicy.html#ir-backwards-compatibility ) ...provides the flexibility we want to make this change without requiring a new IR version. Ie, we're not loosening the FP strictness of existing IR. At worst, we will fail to optimize some previously 'fast' code because it's no longer recognized as 'fast'. This should get fixed as we audit/squash all of the uses of 'isFast()'. Note: an inter-dependent clang commit to use the new API name should closely follow commit. Differential Revision: https://reviews.llvm.org/D39304 llvm-svn: 317488
* [LTO][ThinLTO] Use the linker resolutions to mark global values as dso_local.Sean Fertile2017-11-041-1/+3
| | | | | | | | | | | | | Now that we have a way to mark GlobalValues as local we can use the symbol resolutions that the linker plugin provides as part of lto/thinlto link step to refine the compilers view on what symbols will end up being local. Originally commited as r317374, but reverted in r317395 to update some missed tests. Differential Revision: https://reviews.llvm.org/D35702 llvm-svn: 317408
* Revert "[LTO][ThinLTO] Use the linker resolutions to mark global values ..."Sean Fertile2017-11-041-3/+1
| | | | | | | | | Changes more tests then expected on one of the build bots. reverting to investigate. This reverts https://llvm.org/svn/llvm-project/llvm/trunk@317374 llvm-svn: 317395
* [LTO][ThinLTO] Use the linker resolutions to mark global values as dso_local.Sean Fertile2017-11-031-1/+3
| | | | | | | | | | Now that we have a way to mark GlobalValues as local we can use the symbol resolutions that the linker plugin provides as part of lto/thinlto link step to refine the compilers view on what symbols will end up being local. Differential Revision: https://reviews.llvm.org/D35702 llvm-svn: 317374
* Represent runtime preemption in the IR.Sean Fertile2017-10-261-4/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 an auto-upgrade for LTO section nameSaleem Abdulrasool2017-10-061-1/+1
| | | | | | | | | | | The bitcode reader looks specifically for `__DATA, __objc_catlist` as a section name. However, SVN r304661 removed the spaces (the two names are functionally equivalent but do not compare equally lexicographically). This causes compatibility issues. Add an auto-upgrade path for removing the spaces as well as use the new name in the LTO plugin. llvm-svn: 315086
* [ThinLTO] AliasSummary should not have any referencesTeresa Johnson2017-09-131-3/+2
| | | | | | | | | | | | Summary: References should only be on the aliasee. Reviewers: pcc Subscribers: llvm-commits, inglorion Differential Revision: https://reviews.llvm.org/D37814 llvm-svn: 313158
* IR: Represent -ggnu-pubnames with a flag on the DICompileUnit.Peter Collingbourne2017-09-121-2/+3
| | | | | | | | This allows the flag to be persisted through to LTO. Differential Revision: https://reviews.llvm.org/D37655 llvm-svn: 313078
* [Bitcode] Fix some Clang-tidy modernize-use-using and Include What You Use ↵Eugene Zelenko2017-09-073-69/+96
| | | | | | warnings; other minor fixes (NFC). llvm-svn: 312760
* Canonicalize the representation of empty an expression in ↵Adrian Prantl2017-08-301-9/+13
| | | | | | | | | | | | | | | | DIGlobalVariableExpression This change simplifies code that has to deal with DIGlobalVariableExpression and mirrors how we treat DIExpressions in debug info intrinsics. Before this change there were two ways of representing empty expressions on globals, a nullptr and an empty !DIExpression(). If someone needs to upgrade out-of-tree testcases: perl -pi -e 's/(!DIGlobalVariableExpression\(var: ![0-9]*)\)/\1, expr: !DIExpression())/g' <MYTEST.ll> will catch 95%. llvm-svn: 312144
* Add strictfp attribute to prevent unwanted optimizations of libm callsAndrew Kaylor2017-08-141-0/+3
| | | | | | Differential Revision: https://reviews.llvm.org/D34163 llvm-svn: 310885
* [ThinLTO] Add FunctionAttrs to ThinLTO indexCharles Saternos2017-08-041-13/+39
| | | | | | Adds function attributes to index: ReadNone, ReadOnly, NoRecurse, NoAlias. This attributes will be used for future ThinLTO optimizations that will propagate function attributes across modules. llvm-svn: 310061
* Debug Info: Add a file: field to DIImportedEntity.Adrian Prantl2017-07-191-3/+5
| | | | | | | | | | | | | | | | | | | | | | | DIImportedEntity has a line number, but not a file field. To determine the decl_line/decl_file we combine the line number from the DIImportedEntity with the file from the DIImportedEntity's scope. This does not work correctly when the parent scope is a DINamespace or a DIModule, both of which do not have a source file. This patch adds a file field to DIImportedEntity to unambiguously identify the source location of the using/import declaration. Most testcase updates are mechanical, the interesting one is the removal of the FIXME in test/DebugInfo/Generic/namespace.ll. This fixes PR33822. See https://bugs.llvm.org/show_bug.cgi?id=33822 for more context. <rdar://problem/33357889> https://bugs.llvm.org/show_bug.cgi?id=33822 Differential Revision: https://reviews.llvm.org/D35583 llvm-svn: 308398
* Enhance synchscope representationKonstantin Zhuravlyov2017-07-111-23/+69
| | | | | | | | | | | | | | | | | | | | | | | | | | | OpenCL 2.0 introduces the notion of memory scopes in atomic operations to global and local memory. These scopes restrict how synchronization is achieved, which can result in improved performance. This change extends existing notion of synchronization scopes in LLVM to support arbitrary scopes expressed as target-specific strings, in addition to the already defined scopes (single thread, system). The LLVM IR and MIR syntax for expressing synchronization scopes has changed to use *syncscope("<scope>")*, where <scope> can be "singlethread" (this replaces *singlethread* keyword), or a target-specific name. As before, if the scope is not specified, it defaults to CrossThread/System scope. Implementation details: - Mapping from synchronization scope name/string to synchronization scope id is stored in LLVM context; - CrossThread/System and SingleThread scopes are pre-defined to efficiently check for known scopes without comparing strings; - Synchronization scope names are stored in SYNC_SCOPE_NAMES_BLOCK in the bitcode. Differential Revision: https://reviews.llvm.org/D21723 llvm-svn: 307722
* Object: Teach irsymtab::read() to try to use the irsymtab that we wrote to disk.Peter Collingbourne2017-06-271-4/+28
| | | | | | | | Fixes PR27551. Differential Revision: https://reviews.llvm.org/D33974 llvm-svn: 306488
* Fix build warning on 32-bit targets where sizeof(size_t) < sizeof(long long).Evgeniy Stepanov2017-06-161-2/+4
| | | | llvm-svn: 305535
* [cfi] CFI-ICall for ThinLTO.Evgeniy Stepanov2017-06-161-0/+12
| | | | | | | | Implement ControlFlowIntegrity for indirect function calls in ThinLTO. Design follows the RFC in llvm-dev, see https://groups.google.com/d/msg/llvm-dev/MgUlaphu4Qc/kywu0AqjAQAJ llvm-svn: 305533
* Apply summary-based dead stripping to regular LTO modules with summaries.Peter Collingbourne2017-06-151-13/+20
| | | | | | | | | | | | | | | If a regular LTO module has a summary index, then instead of linking it into the combined regular LTO module right away, add it to the combined summary index and associate it with a special module that represents the combined regular LTO module. Any such modules are linked during LTO::run(), at which time we use the results of summary-based dead stripping to control whether to link prevailing symbols. Differential Revision: https://reviews.llvm.org/D33922 llvm-svn: 305482
* IR: Tweak the API around adding modules to the summary index.Peter Collingbourne2017-06-141-15/+15
| | | | | | | | | | | | | The current name (addModulePath) and return value (ModulePathStringTableTy::iterator) is a little confusing. This API adds a module, not just a path. And the iterator is basically just an implementation detail of the summary index. Address both of those issues by renaming to addModule and introducing a ModuleSummaryIndex::ModuleInfo type that the function returns. Differential Revision: https://reviews.llvm.org/D34124 llvm-svn: 305422
* Align definition of DW_OP_plus with DWARF spec [3/3]Florian Hahn2017-06-141-31/+92
| | | | | | | | | | | | | | | | | | | | | | | | Summary: This patch is part of 3 patches that together form a single patch, but must be introduced in stages in order not to break things. The way that LLVM interprets DW_OP_plus in DIExpression nodes is basically that of the DW_OP_plus_uconst operator since LLVM expects an unsigned constant operand. This unnecessarily restricts the DW_OP_plus operator, preventing it from being used to describe the evaluation of runtime values on the expression stack. These patches try to align the semantics of DW_OP_plus and DW_OP_minus with that of the DWARF definition, which pops two elements off the expression stack, performs the operation and pushes the result back on the stack. This is done in three stages: • The first patch (LLVM) adds support for DW_OP_plus_uconst. • The second patch (Clang) contains changes all its uses from DW_OP_plus to DW_OP_plus_uconst. • The third patch (LLVM) changes the semantics of DW_OP_plus and DW_OP_minus to be in line with its DWARF meaning. This patch includes the bitcode upgrade from legacy DIExpressions. Patch by Sander de Smalen. Reviewers: echristo, pcc, aprantl Reviewed By: aprantl Subscribers: fhahn, javed.absar, aprantl, llvm-commits Differential Revision: https://reviews.llvm.org/D33894 llvm-svn: 305386
* IR: Replace the "Linker Options" module flag with "llvm.linker.options" ↵Peter Collingbourne2017-06-121-0/+10
| | | | | | | | | | named metadata. The new metadata is easier to manipulate than module flags. Differential Revision: https://reviews.llvm.org/D31349 llvm-svn: 305227
* Bitcode: Introduce a BitcodeFileContents data type. NFCI.Peter Collingbourne2017-06-081-7/+15
| | | | | | | | | | This data type includes the contents of a bitcode file. Right now a bitcode file can only contain modules, but a later change will add a symbol table. Differential Revision: https://reviews.llvm.org/D33969 llvm-svn: 305019
* Sort the remaining #include lines in include/... and lib/....Chandler Carruth2017-06-062-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | I did this a long time ago with a janky python script, but now clang-format has built-in support for this. I fed clang-format every line with a #include and let it re-sort things according to the precise LLVM rules for include ordering baked into clang-format these days. I've reverted a number of files where the results of sorting includes isn't healthy. Either places where we have legacy code relying on particular include ordering (where possible, I'll fix these separately) or where we have particular formatting around #include lines that I didn't want to disturb in this patch. This patch is *entirely* mechanical. If you get merge conflicts or anything, just ignore the changes in this patch and run clang-format over your #include lines in the files. Sorry for any noise here, but it is important to keep these things stable. I was seeing an increasing number of patches with irrelevant re-ordering of #include lines because clang-format was used. This patch at least isolates that churn, makes it easy to skip when resolving conflicts, and gets us to a clean baseline (again). llvm-svn: 304787
* (NFC) Track global summary liveness in GVFlags.Evgeniy Stepanov2017-06-011-3/+3
| | | | | | | | Replace GVFlags::LiveRoot with GVFlags::Live and use that instead of all the DeadSymbols sets. This is refactoring in order to make liveness information available in the RegularLTO pipeline. llvm-svn: 304466
* [IR] De-virtualize ~Value to save a vptrReid Kleckner2017-05-182-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Implements PR889 Removing the virtual table pointer from Value saves 1% of RSS when doing LTO of llc on Linux. The impact on time was positive, but too noisy to conclusively say that performance improved. Here is a link to the spreadsheet with the original data: https://docs.google.com/spreadsheets/d/1F4FHir0qYnV0MEp2sYYp_BuvnJgWlWPhWOwZ6LbW7W4/edit?usp=sharing This change makes it invalid to directly delete a Value, User, or Instruction pointer. Instead, such code can be rewritten to a null check and a call Value::deleteValue(). Value objects tend to have their lifetimes managed through iplist, so for the most part, this isn't a big deal. However, there are some places where LLVM deletes values, and those places had to be migrated to deleteValue. I have also created llvm::unique_value, which has a custom deleter, so it can be used in place of std::unique_ptr<Value>. I had to add the "DerivedUser" Deleter escape hatch for MemorySSA, which derives from User outside of lib/IR. Code in IR cannot include MemorySSA headers or call the MemoryAccess object destructors without introducing a circular dependency, so we need some level of indirection. Unfortunately, no class derived from User may have any virtual methods, because adding a virtual method would break User::getHungOffOperands(), which assumes that it can find the use list immediately prior to the User object. I've added a static_assert to the appropriate OperandTraits templates to help people avoid this trap. Reviewers: chandlerc, mehdi_amini, pete, dberlin, george.burgess.iv Reviewed By: chandlerc Subscribers: krytarowski, eraman, george.burgess.iv, mzolotukhin, Prazek, nlewycky, hans, inglorion, pcc, tejohnson, dberlin, llvm-commits Differential Revision: https://reviews.llvm.org/D31261 llvm-svn: 303362
* [MetadataLoader] Remove unused Vector. NFCI.Davide Italiano2017-05-161-1/+1
| | | | llvm-svn: 303196
* Remove ignore-empty-index-file optionTeresa Johnson2017-05-121-8/+2
| | | | | | | | | | | | | | | Summary: As discussed in the D32195 review thread and on IRC, remove this option and replace with parameter, which will be set to true when invoked from clang in the context of a ThinLTO distributed backend. Reviewers: pcc Subscribers: mehdi_amini, llvm-commits Differential Revision: https://reviews.llvm.org/D33133 llvm-svn: 302939
* [IR] Allow attributes with global variablesJaved Absar2017-05-111-1/+6
| | | | | | | | | | | | | This patch extends llvm-ir to allow attributes to be set on global variables. An RFC was sent out earlier by my colleague James Molloy: http://lists.llvm.org/pipermail/cfe-dev/2017-March/053100.html A key part of that proposal was to extend LLVM-IR to carry attributes on global variables. This generic feature could be useful for multiple purposes. In our present context, it would be useful to carry user specified sections for bss/rodata/data. Reviewed by: Jonathan Roelofs, Reid Kleckner Differential Revision: https://reviews.llvm.org/D32009 llvm-svn: 302794
* Re-apply r302108, "IR: Use pointers instead of GUIDs to represent edges in ↵Peter Collingbourne2017-05-041-36/+41
| | | | | | | | the module summary. NFCI." with a fix for the clang backend. llvm-svn: 302176
* Revert "IR: Use pointers instead of GUIDs to represent edges in the module ↵Eric Liu2017-05-041-41/+36
| | | | | | | | | | summary. NFCI." This reverts commit r302108. This causes crash in clang bootstrap with LTO. Contacted the auther in the original commit. llvm-svn: 302140
* IR: Use pointers instead of GUIDs to represent edges in the module summary. ↵Peter Collingbourne2017-05-041-36/+41
| | | | | | | | | | | | | | | | | | | | NFCI. When profiling a no-op incremental link of Chromium I found that the functions computeImportForFunction and computeDeadSymbols were consuming roughly 10% of the profile. The goal of this change is to improve the performance of those functions by changing the map lookups that they were previously doing into pointer dereferences. This is achieved by changing the ValueInfo data structure to be a pointer to an element of the global value map owned by ModuleSummaryIndex, and changing reference lists in the GlobalValueSummary to hold ValueInfos instead of GUIDs. This means that a ValueInfo will take a client directly to the summary list for a given GUID. Differential Revision: https://reviews.llvm.org/D32471 llvm-svn: 302108
* Fix a pessimising move warning.Peter Collingbourne2017-05-011-5/+1
| | | | llvm-svn: 301852
* Bitcode: Make the summary reader responsible for merging. NFCI.Peter Collingbourne2017-05-011-23/+62
| | | | | | | | | This is to prepare for an upcoming change which uses pointers instead of GUIDs to represent references. Differential Revision: https://reviews.llvm.org/D32469 llvm-svn: 301843
* Object: Remove ModuleSummaryIndexObjectFile class.Peter Collingbourne2017-05-011-0/+18
| | | | | | Differential Revision: https://reviews.llvm.org/D32195 llvm-svn: 301832
* Rename WeakVH to WeakTrackingVH; NFCSanjoy Das2017-05-012-2/+2
| | | | | | This relands r301424. llvm-svn: 301812
* Remove set but unused variable in BitcodeReader.cpp. NFC.Hans Wennborg2017-04-281-4/+0
| | | | llvm-svn: 301713
* Remove line and file from DINamespace.Adrian Prantl2017-04-281-4/+8
| | | | | | | | | | | | | | Fixes the issue highlighted in http://lists.llvm.org/pipermail/cfe-dev/2014-June/037500.html. The DW_AT_decl_file and DW_AT_decl_line attributes on namespaces can prevent LLVM from uniquing types that are in the same namespace. They also don't carry any meaningful information. rdar://problem/17484998 Differential Revision: https://reviews.llvm.org/D32648 llvm-svn: 301706
* Add speculatable function attributeMatt Arsenault2017-04-281-0/+3
| | | | | | | | This attribute tells the optimizer that the function may be speculated. Patch by Tom Stellard llvm-svn: 301680
* Bitcode: Do not remove empty summary entries when reading a per-module summary.Peter Collingbourne2017-04-281-10/+0
| | | | | | | | This became no longer necessary after D19462 landed, and will be incompatible with an upcoming change to the summary data structures that changes how we represent references. llvm-svn: 301660
* Turn DISubprogram into a variable-length node.Adrian Prantl2017-04-261-2/+2
| | | | | | | | | | | | | | | | | | | | DISubprogram currently has 10 pointer operands, several of which are often nullptr. This patch reduces the amount of memory allocated by DISubprogram by rearranging the operands such that containing type, template params, and thrown types come last, and are only allocated when they are non-null (or followed by non-null operands). This patch also eliminates the entirely unused DisplayName operand. This saves up to 4 pointer operands per DISubprogram. (I tried measuring the effect on peak memory usage on an LTO link of an X86 llc, but the results were very noisy). This reapplies r301498 with an attempted workaround for g++. Differential Revision: https://reviews.llvm.org/D32560 llvm-svn: 301501
* Revert "Turn DISubprogram into a variable-length node."Adrian Prantl2017-04-261-2/+2
| | | | | | This reverts commit r301498 while investigating bot breakage. llvm-svn: 301499
* Turn DISubprogram into a variable-length node.Adrian Prantl2017-04-261-2/+2
| | | | | | | | | | | | | | | | DISubprogram currently has 10 pointer operands, several of which are often nullptr. This patch reduces the amount of memory allocated by DISubprogram by rearranging the operands such that containing type, template params, and thrown types come last, and are only allocated when they are non-null (or followed by non-null operands). This patch also eliminates the entirely unused DisplayName operand. This saves up to 4 pointer operands per DISubprogram. (I tried measuring the effect on peak memory usage on an LTO link of an X86 llc, but the results were very noisy). llvm-svn: 301498
* Add support for DW_TAG_thrown_type.Adrian Prantl2017-04-261-23/+25
| | | | | | | | | | | | | | | | | | | | For Swift we would like to be able to encode the error types that a function may throw, so the debugger can display them alongside the function's return value when finish-ing a function. DWARF defines DW_TAG_thrown_type (intended to be used for C++ throw() declarations) that is a perfect fit for this purpose. This patch wires up support for DW_TAG_thrown_type in LLVM by adding a list of thrown types to DISubprogram. To offset the cost of the extra pointer, there is a follow-up patch that turns DISubprogram into a variable-length node. rdar://problem/29481673 Differential Revision: https://reviews.llvm.org/D32559 llvm-svn: 301489
* Reverts commit r301424, r301425 and r301426Sanjoy Das2017-04-262-2/+2
| | | | | | | | | | | | Commits were: "Use WeakVH instead of WeakTrackingVH in AliasSetTracker's UnkownInsts" "Add a new WeakVH value handle; NFC" "Rename WeakVH to WeakTrackingVH; NFC" The changes assumed pointers are 8 byte aligned on all architectures. llvm-svn: 301429
* Rename WeakVH to WeakTrackingVH; NFCSanjoy Das2017-04-262-2/+2
| | | | | | | | | | | | | | | | Summary: I plan to use WeakVH to mean "nulls itself out on deletion, but does not track RAUW" in a subsequent commit. Reviewers: dblaikie, davide Reviewed By: davide Subscribers: arsenm, mehdi_amini, mcrosier, mzolotukhin, jfb, llvm-commits, nhaehnle Differential Revision: https://reviews.llvm.org/D32266 llvm-svn: 301424
* PR32382: Fix emitting complex DWARF expressions.Adrian Prantl2017-04-183-5/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The DWARF specification knows 3 kinds of non-empty simple location descriptions: 1. Register location descriptions - describe a variable in a register - consist of only a DW_OP_reg 2. Memory location descriptions - describe the address of a variable 3. Implicit location descriptions - describe the value of a variable - end with DW_OP_stack_value & friends The existing DwarfExpression code is pretty much ignorant of these restrictions. This used to not matter because we only emitted very short expressions that we happened to get right by accident. This patch makes DwarfExpression aware of the rules defined by the DWARF standard and now chooses the right kind of location description for each expression being emitted. This would have been an NFC commit (for the existing testsuite) if not for the way that clang describes captured block variables. Based on how the previous code in LLVM emitted locations, DW_OP_deref operations that should have come at the end of the expression are put at its beginning. Fixing this means changing the semantics of DIExpression, so this patch bumps the version number of DIExpression and implements a bitcode upgrade. There are two major changes in this patch: I had to fix the semantics of dbg.declare for describing function arguments. After this patch a dbg.declare always takes the *address* of a variable as the first argument, even if the argument is not an alloca. When lowering a DBG_VALUE, the decision of whether to emit a register location description or a memory location description depends on the MachineLocation — register machine locations may get promoted to memory locations based on their DIExpression. (Future) optimization passes that want to salvage implicit debug location for variables may do so by appending a DW_OP_stack_value. For example: DBG_VALUE, [RBP-8] --> DW_OP_fbreg -8 DBG_VALUE, RAX --> DW_OP_reg0 +0 DBG_VALUE, RAX, DIExpression(DW_OP_deref) --> DW_OP_reg0 +0 All testcases that were modified were regenerated from clang. I also added source-based testcases for each of these to the debuginfo-tests repository over the last week to make sure that no synchronized bugs slip in. The debuginfo-tests compile from source and run the debugger. https://bugs.llvm.org/show_bug.cgi?id=32382 <rdar://problem/31205000> Differential Revision: https://reviews.llvm.org/D31439 llvm-svn: 300522
* Bitcode: Add a string table to the bitcode format.Peter Collingbourne2017-04-171-78/+237
| | | | | | | | | | | | | | | | | | | | | | | 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
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