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* Add IR support, ELF section and user documentation for partitioning feature.Peter Collingbourne2019-05-291-0/+2
| | | | | | | | | | | | The partitioning feature was proposed here: http://lists.llvm.org/pipermail/llvm-dev/2019-February/130583.html This is mostly just documentation. The feature itself will be contributed in subsequent patches. Differential Revision: https://reviews.llvm.org/D60242 llvm-svn: 361923
* [ELF] Implement Dependent Libraries FeatureBen Dunbobbin2019-05-171-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements a limited form of autolinking primarily designed to allow either the --dependent-library compiler option, or "comment lib" pragmas ( https://docs.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp?view=vs-2017) in C/C++ e.g. #pragma comment(lib, "foo"), to cause an ELF linker to automatically add the specified library to the link when processing the input file generated by the compiler. Currently this extension is unique to LLVM and LLD. However, care has been taken to design this feature so that it could be supported by other ELF linkers. The design goals were to provide: - A simple linking model for developers to reason about. - The ability to to override autolinking from the linker command line. - Source code compatibility, where possible, with "comment lib" pragmas in other environments (MSVC in particular). Dependent library support is implemented differently for ELF platforms than on the other platforms. Primarily this difference is that on ELF we pass the dependent library specifiers directly to the linker without manipulating them. This is in contrast to other platforms where they are mapped to a specific linker option by the compiler. This difference is a result of the greater variety of ELF linkers and the fact that ELF linkers tend to handle libraries in a more complicated fashion than on other platforms. This forces us to defer handling the specifiers to the linker. In order to achieve a level of source code compatibility with other platforms we have restricted this feature to work with libraries that meet the following "reasonable" requirements: 1. There are no competing defined symbols in a given set of libraries, or if they exist, the program owner doesn't care which is linked to their program. 2. There may be circular dependencies between libraries. The binary representation is a mergeable string section (SHF_MERGE, SHF_STRINGS), called .deplibs, with custom type SHT_LLVM_DEPENDENT_LIBRARIES (0x6fff4c04). The compiler forms this section by concatenating the arguments of the "comment lib" pragmas and --dependent-library options in the order they are encountered. Partial (-r, -Ur) links are handled by concatenating .deplibs sections with the normal mergeable string section rules. As an example, #pragma comment(lib, "foo") would result in: .section ".deplibs","MS",@llvm_dependent_libraries,1 .asciz "foo" For LTO, equivalent information to the contents of a the .deplibs section can be retrieved by the LLD for bitcode input files. LLD processes the dependent library specifiers in the following way: 1. Dependent libraries which are found from the specifiers in .deplibs sections of relocatable object files are added when the linker decides to include that file (which could itself be in a library) in the link. Dependent libraries behave as if they were appended to the command line after all other options. As a consequence the set of dependent libraries are searched last to resolve symbols. 2. It is an error if a file cannot be found for a given specifier. 3. Any command line options in effect at the end of the command line parsing apply to the dependent libraries, e.g. --whole-archive. 4. The linker tries to add a library or relocatable object file from each of the strings in a .deplibs section by; first, handling the string as if it was specified on the command line; second, by looking for the string in each of the library search paths in turn; third, by looking for a lib<string>.a or lib<string>.so (depending on the current mode of the linker) in each of the library search paths. 5. A new command line option --no-dependent-libraries tells LLD to ignore the dependent libraries. Rationale for the above points: 1. Adding the dependent libraries last makes the process simple to understand from a developers perspective. All linkers are able to implement this scheme. 2. Error-ing for libraries that are not found seems like better behavior than failing the link during symbol resolution. 3. It seems useful for the user to be able to apply command line options which will affect all of the dependent libraries. There is a potential problem of surprise for developers, who might not realize that these options would apply to these "invisible" input files; however, despite the potential for surprise, this is easy for developers to reason about and gives developers the control that they may require. 4. This algorithm takes into account all of the different ways that ELF linkers find input files. The different search methods are tried by the linker in most obvious to least obvious order. 5. I considered adding finer grained control over which dependent libraries were ignored (e.g. MSVC has /nodefaultlib:<library>); however, I concluded that this is not necessary: if finer control is required developers can fall back to using the command line directly. RFC thread: http://lists.llvm.org/pipermail/llvm-dev/2019-March/131004.html. Differential Revision: https://reviews.llvm.org/D60274 llvm-svn: 360984
* 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
* [Hexagon] Handle Hexagon's SHF_HEX_GPREL section flagKrzysztof Parzyszek2018-11-091-0/+3
| | | | llvm-svn: 346494
* Revert "Add a warning if someone attempts to add extra section flags to ↵Eric Christopher2018-08-051-36/+16
| | | | | | | | | | | sections" There are a bunch of edge cases and inconsistencies in how we're emitting sections cause this warning to fire and it needs more work. This reverts commit r335558. llvm-svn: 338968
* Remove trailing spaceFangrui Song2018-07-301-1/+1
| | | | | | sed -Ei 's/[[:space:]]+$//' include/**/*.{def,h,td} lib/**/*.{cpp,h} llvm-svn: 338293
* Add an entry for rodata constant merge sections to the defaultEric Christopher2018-07-021-0/+3
| | | | | | | | | | section flags in the ELF assembler. This matches the defaults given in the rest of MC. Fixes PR37997 where we couldn't assemble our own assembly output without warnings. llvm-svn: 336072
* Add a warning if someone attempts to add extra section flags to sectionsEric Christopher2018-06-251-16/+33
| | | | | | with well defined semantics like .rodata. llvm-svn: 335558
* Remove FIXME comment about WIP.Eric Christopher2018-06-211-1/+0
| | | | | | | This is the only line other than the function signature remaining of the original patch. llvm-svn: 335208
* [MC] Add assembler support for .cg_profile.Michael J. Spencer2018-06-021-0/+45
| | | | | | | | | | | | | | | Object FIle Representation At codegen time this is emitted into the ELF file a pair of symbol indices and a weight. In assembly it looks like: .cg_profile a, b, 32 .cg_profile freq, a, 11 .cg_profile freq, b, 20 When writing an ELF file these are put into a SHT_LLVM_CALL_GRAPH_PROFILE (0x6fff4c02) section as (uint32_t, uint32_t, uint64_t) tuples as (from symbol index, to symbol index, weight). Differential Revision: https://reviews.llvm.org/D44965 llvm-svn: 333823
* Reflow formatting after previous NFC commit.Eric Christopher2018-04-241-6/+6
| | | | llvm-svn: 330676
* Change if-conditionals to else-if as they should all be mutually exclusive.Eric Christopher2018-04-241-3/+3
| | | | | | No functional change intended. llvm-svn: 330675
* Delay creating an alias for @@@.Rafael Espindola2018-03-091-2/+1
| | | | | | | | | | | With this we only create an alias for @@@ once we know if it should use @ or @@. This avoids last minutes renames and hacks to handle MS names. This only handles the ELF writer. LTO still has issues with @@@ aliases. llvm-svn: 327160
* Don't treat .symver as a regular alias definition.Rafael Espindola2018-03-091-3/+0
| | | | | | | | | | | | | | This patch starts simplifying the handling of .symver. For now it just moves the responsibility for creating an alias down to the streamer. With that the asm streamer can pass a .symver unchanged, which is nice since gas cannot parse "foo@bar = zed". In a followup I hope to move the handling down to the writer so that we don't need special hacks for avoiding breaking names with @@@ on windows. llvm-svn: 327101
* CodeGen: support an extension to pass linker options on ELFSaleem Abdulrasool2018-01-301-0/+2
| | | | | | | | | | | | | | | | | | Introduce an extension to support passing linker options to the linker. These would be ignored by older linkers, but newer linkers which support this feature would be able to process the linker. Emit a special discarded section `.linker-option`. The content of this section is a pair of strings (key, value). The key is a type identifier for the parameter. This allows for an argument free parameter that will be processed by the linker with the value being the parameter. As an example, `lib` identifies a library to be linked against, traditionally the `-l` argument for Unix-based linkers with the parameter being the library name. Thanks to James Henderson, Cary Coutant, Rafael Espinolda, Sean Silva for the valuable discussion on the design of this feature. llvm-svn: 323783
* [MC] - Stop ignoring invalid meta data symbols.George Rimar2017-12-311-1/+1
| | | | | | | | | | | Previously llvm-mc would silently accept code from testcase, that contains invalid metadata symbol in section declaration. Patch fixes the issue. Differential revision: https://reviews.llvm.org/D41641 llvm-svn: 321599
* [MC] - Disallow invalid section groups declarations.George Rimar2017-12-251-2/+2
| | | | | | | | | | | | This fixes parseGroup() so that it always sets error condition on error. Previously it was not done, because parseIdentifier looks never do that, assuming that caller should do it if he wants to. So previously cases from test were silently accepted and produced broken output. Differential revision: https://reviews.llvm.org/D41559 llvm-svn: 321439
* [MC] - Teach llvm-mc to handle comdats whose names are numbers.George Rimar2017-12-241-1/+5
| | | | | | | | | | | | | | | Currently llvm-mc ignores COMDATs whose names are numbers, for example following code: .section .foo,"G",@progbits,123,comdat would produce no COMDATs at all. Patch fixes the issue. Differential revision: https://reviews.llvm.org/D41552 llvm-svn: 321419
* Remove unused variables. No functionality change.Benjamin Kramer2017-10-081-1/+0
| | | | llvm-svn: 315185
* [MC] - llvm-mc hangs on non-english characters.George Rimar2017-10-051-1/+1
| | | | | | | | | | | | | | | | | | Currently llvm-mc just hangs inside infinite loop while trying to parse file which has ".section .с" inside, where section name is non-english character. Patch fixes the issue. In this patch I also moved content of non-english-characters.s to test/MC/AsmParser/Inputs folder so that non-english-characters.s becomes a single testcase for all invalid inputs containing non-english symbols. That is convinent because llvm-mc otherwise tries to parse and tokenize the whole testcase file with tools invocations and it is harder to isolate the issue. Differential revision: https://reviews.llvm.org/D38545 llvm-svn: 314973
* MC, Object: Reserve a section type, SHT_LLVM_ODRTAB, for the ODR table.Peter Collingbourne2017-06-141-0/+2
| | | | | | | | | | | | | | This is part of the ODR checker proposal: http://lists.llvm.org/pipermail/llvm-dev/2017-June/113820.html Per discussion on the gnu-gabi mailing list [1] the section type range 0x6fff4c00..0x6fff4cff is reserved for LLVM. [1] https://sourceware.org/ml/gnu-gabi/2017-q2/msg00030.html Differential Revision: https://reviews.llvm.org/D33978 llvm-svn: 305407
* Move Object format code to lib/BinaryFormat.Zachary Turner2017-06-071-1/+1
| | | | | | | | | | | | This creates a new library called BinaryFormat that has all of the headers from llvm/Support containing structure and layout definitions for various types of binary formats like dwarf, coff, elf, etc as well as the code for identifying a file from its magic. Differential Revision: https://reviews.llvm.org/D33843 llvm-svn: 304864
* Sort the remaining #include lines in include/... and lib/....Chandler Carruth2017-06-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | 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
* [MC] Set defaults based on section names and support name suffixesPetr Hosek2017-04-041-6/+15
| | | | | | | | | | | | | Set correct default flags and section type based on its name for .text, .data, .bss, .init_array, .fini_array, .preinit_array, .tdata, and .tbss and support section name suffixes for .data.*, .rodata.*, .text.*, .bss.*, .tdata.* and .tbss.* which matches the behavior of GAS. Fixes PR31888. Differential Revision: https://reviews.llvm.org/D30229 llvm-svn: 299484
* Change section flag character for SHF_LINK_ORDER to "o".Evgeniy Stepanov2017-04-041-1/+1
| | | | | | | | GAS uses "m" as a compatibility alias for "M" (SHF_MERGE). "o" is free, except on ia64, where it already means SHF_LINK_ORDER. llvm-svn: 299479
* Add default typo to .tbss.*Rafael Espindola2017-03-221-0/+2
| | | | | | This matches gas behavior and is part of pr31888. llvm-svn: 298508
* Set the default type for .bss.foo.Rafael Espindola2017-03-221-0/+2
| | | | | | This matches gas and is part of pr31888. llvm-svn: 298506
* Produce INIT_ARRAY for sections named .init_array.*Rafael Espindola2017-03-221-1/+5
| | | | | | | These sections are merged together by the linker, so they should have the same time. llvm-svn: 298505
* [Asm] Don't list '@<type>' in diag when '@' is a commentOliver Stannard2017-03-171-2/+6
| | | | | | | | This fixes https://bugs.llvm.org//show_bug.cgi?id=31280 Differential revision: https://reviews.llvm.org/D31026 llvm-svn: 298067
* Fix asm printing of associated sections.Evgeniy Stepanov2017-03-141-8/+8
| | | | | | | Make MCSectionELF::AssociatedSection be a link to a symbol, because that's how it works in the assembly, and use it in the asm printer. llvm-svn: 297769
* [MC] Accept a numeric value as an ELF section header's typeSimon Atanasyan2017-03-101-2/+5
| | | | | | | | | | | | | | | | | | | | | | GAS supports specification of section header's type using a numeric value [1]. This patch brings the same functionality to LLVM. That allows to setup some target-specific section types belong to the SHT_LOPROC - SHT_HIPROC range. If we attempt to print unknown section type, MCSectionELF class shows an error message. It's better than print sole '@' sign without any section type name. In case of MIPS, example of such section's type is SHT_MIPS_DWARF. Without the patch we will have to implement some workarounds in probably not-MIPS-specific part of code base to convert SHT_MIPS_DWARF to the @progbits while printing assembly and to assign SHT_MIPS_DWARF for @progbits sections named .debug_* if we encounter such section in an input assembly. [1] https://sourceware.org/binutils/docs/as/Section.html Differential Revision: https://reviews.llvm.org/D29719 llvm-svn: 297446
* Perform symbol binding for .symver versioned symbolsTeresa Johnson2017-03-091-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: In a .symver assembler directive like: .symver name, name2@@nodename "name2@@nodename" should get the same symbol binding as "name". While the ELF object writer is updating the symbol binding for .symver aliases before emitting the object file, not doing so when the module inline assembly is handled by the RecordStreamer is causing the wrong behavior in *LTO mode. E.g. when "name" is global, "name2@@nodename" must also be marked as global. Otherwise, the symbol is skipped when iterating over the LTO InputFile symbols (InputFile::Symbol::shouldSkip). So, for example, when performing any *LTO via the gold-plugin, the versioned symbol definition is not recorded by the plugin and passed back to the linker. If the object was in an archive, and there were no other symbols needed from that object, the object would not be included in the final link and references to the versioned symbol are undefined. The llvm-lto2 tests added will give an error about an unused symbol resolution without the fix. Reviewers: rafael, pcc Reviewed By: pcc Subscribers: mehdi_amini, llvm-commits Differential Revision: https://reviews.llvm.org/D30485 llvm-svn: 297332
* Make it possible to set SHF_LINK_ORDER explicitly.Rafael Espindola2017-02-091-2/+25
| | | | | | | This will make it possible to add support for gcing user metadata (asan for example). llvm-svn: 294589
* [MC] Fix some Clang-tidy modernize and Include What You Use warnings; other ↵Eugene Zelenko2017-02-071-7/+18
| | | | | | minor fixes (NFC). llvm-svn: 294369
* Move more code to helper functions. NFC.Rafael Espindola2017-01-311-39/+60
| | | | llvm-svn: 293715
* Move some code to a helper function. NFC.Rafael Espindola2017-01-311-48/+59
| | | | llvm-svn: 293712
* Allow ELF section flags to be specified numericallyPrakhar Bahuguna2016-12-151-0/+4
| | | | | | | | | | | | | | | | | Summary: GAS already allows flags for sections to be specified directly as a numeric value. This functionality is particularly useful for setting processor or application-specific values that may not be directly supported or understood by LLVM. This patch allows LLVM to use numeric section flag values verbatim if specified by the assembly file. Reviewers: grosbach, rafael, t.p.northover, rengolin Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D27451 llvm-svn: 289785
* [ARM] Implement execute-only support in CodeGenPrakhar Bahuguna2016-12-151-0/+3
| | | | | | | | | | | | | | | | | | | | This implements execute-only support for ARM code generation, which prevents the compiler from generating data accesses to code sections. The following changes are involved: * Add the CodeGen option "-arm-execute-only" to the ARM code generator. * Add the clang flag "-mexecute-only" as well as the GCC-compatible alias "-mpure-code" to enable this option. * When enabled, literal pools are replaced with MOVW/MOVT instructions, with VMOV used in addition for floating-point literals. As the MOVT instruction is required, execute-only support is only available in Thumb mode for targets supporting ARMv8-M baseline or Thumb2. * Jump tables are placed in data sections when in execute-only mode. * The execute-only text section is assigned section ID 0, and is marked as unreadable with the SHF_ARM_PURECODE flag with symbol 'y'. This also overrides selection of ELF sections for globals. llvm-svn: 289784
* [MC] Cleanup Error Handling in AsmParserNirav Dave2016-07-181-0/+8
| | | | | | | | | | | | | | | Add parseToken and compatriot functions to stitch error checks in straight linear code. As part of this fix some erronous handling of directives where the EndOfStatement token either was not checked or Lexed on termination. Reviewers: rnk, majnemer Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D22312 llvm-svn: 275795
* Provide support for preserving assembly commentsNirav Dave2016-07-111-0/+1
| | | | | | | | | | | | | | | | | Preserve assembly comments from input in output assembly and flags to toggle property. This is on by default for inline assembly and off in llvm-mc. Parsed comments are emitted immediately before an EOL which generally places them on the expected line. Reviewers: rtrieu, dwmw2, rnk, majnemer Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D20020 llvm-svn: 275058
* Apply clang-tidy's modernize-loop-convert to lib/MC.Benjamin Kramer2016-06-261-2/+2
| | | | | | Only minor manual fixes. No functionality change intended. llvm-svn: 273814
* [ELF][gcc compatibility]: support section names with special characters ↵Marina Yatsina2016-03-221-8/+9
| | | | | | | | | | | | (e.g. "/") Adding support for section names with special characters in them (e.g. "/"). GCC successfully compiles such section names. This also fixes PR24520. Differential Revision: http://reviews.llvm.org/D15678 llvm-svn: 264038
* Stop producing .data.rel sections.Rafael Espindola2015-11-181-8/+6
| | | | | | | | | | | | | | | | | If a section is rw, it is irrelevant if the dynamic linker will write to it or not. It looks like llvm implemented this because gcc was doing it. It looks like gcc implemented this in the hope that it would put all the relocated items close together and speed up the dynamic linker. There are two problem with this: * It doesn't work. Both bfd and gold will map .data.rel to .data and concatenate the input sections in the order they are seen. * If we want a feature like that, it can be implemented directly in the linker since it knowns where the dynamic relocations are. llvm-svn: 253436
* Drop prelink support.Rafael Espindola2015-11-171-8/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The way prelink used to work was * The compiler decides if a given section only has relocations that are know to point to the same DSO. If so, it names it .data.rel.ro.local<something>. * The static linker puts all of these together. * The prelinker program assigns addresses to each library and resolves the local relocations. There are many problems with this: * It is incompatible with address space randomization. * The information passed by the compiler is redundant. The linker knows if a given relocation is in the same DSO or not. If could sort by that if so desired. * There are newer ways of speeding up DSO (gnu hash for example). * Even if we want to implement this again in the compiler, the previous implementation is pretty broken. It talks about relocations that are "resolved by the static linker". If they are resolved, there are none left for the prelinker. What one needs to track is if an expression will require only dynamic relocations that point to the same DSO. At this point it looks like the prelinker is an historical curiosity. For example, fedora has retired it because it failed to build for two releases (http://pkgs.fedoraproject.org/cgit/prelink.git/commit/?id=eb43100a8331d91c801ee3dcdb0a0bb9babfdc1f) This patch removes support for it. That is, it stops printing the ".local" sections. llvm-svn: 253280
* Fix PR23872: Integrated assembler error message when using .type directive ↵Gabor Ballabas2015-07-011-4/+10
| | | | | | | | | | | with @ in AArch32 assembly. The AArch32 assembler parses the '@' as a comment symbol, so the error message shouldn't suggest that '@<type>' is a valid replacement when assembling for AArch32 target. Differential Revision: http://reviews.llvm.org/D10651 llvm-svn: 241149
* Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)Alexander Kornienko2015-06-231-1/+1
| | | | | | Apparently, the style needs to be agreed upon first. llvm-svn: 240390
* Fixed/added namespace ending comments using clang-tidy. NFCAlexander Kornienko2015-06-191-1/+1
| | | | | | | | | | | | | The patch is generated using this command: tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \ -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \ llvm/lib/ Thanks to Eugene Kosov for the original patch! llvm-svn: 240137
* Create a MCSymbolELF.Rafael Espindola2015-06-021-3/+3
| | | | | | | | | This create a MCSymbolELF class and moves SymbolSize since only ELF needs a size expression. This reduces the size of MCSymbol from 56 to 48 bytes. llvm-svn: 238801
* MC: Clean up MCExpr naming. NFC.Jim Grosbach2015-05-301-1/+1
| | | | llvm-svn: 238634
* There is only one current section.Rafael Espindola2015-05-271-3/+5
| | | | | | | | | | | | | | | | | Both MCStreamer and MCObjectStreamer were maintaining a current section variable and they were slightly out of sync. I don't think this was observable, but was inefficient and error prone. Changing this requires a few cascading changes: * SwitchSection has to call ChangeSection earlier for ChangeSection to see the old section. * With that change, ChangeSection cannot call EmitLabel, since during ChangeSection we are still in the old section. * When the object streamer requires a begin label, just reused the existing generic support for begin labels instead of calling EmitLabel directly. llvm-svn: 238357
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