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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
* [MC] Clean up unused inline function and non-anchor defaulted destructors; NFCIHubert Tong2019-02-091-2/+0
| | | | | | | | | | | | | | | | | | | | | | Summary: Take care of some missing clean-ups that belong with r249548 and some other copy/paste that had happened. In particular, the destructors are no longer vtable anchors after r249548; and `setSectionName` in `MCSectionWasm` is private and unused since r313058 culled its only caller. The destructors are now implicitly defined, and the unused function is removed. Reviewers: nemanjai, jasonliu, grosbach Reviewed By: nemanjai Subscribers: sbc100, aheejin, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D57182 llvm-svn: 353597
* 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
* [MC] Add assembler support for .cg_profile.Michael J. Spencer2018-06-021-0/+2
| | | | | | | | | | | | | | | 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
* 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
* [Triple] Add isThumb and isARM functions.Florian Hahn2017-08-121-2/+1
| | | | | | | | | | | | | | | | | | | Summary: isThumb returns true for Thumb triples (little and big endian), isARM returns true for ARM triples (little and big endian). There are a few more checks using arm/thumb that are not covered by those functions, e.g. that the architecture is either ARM or Thumb (little endian) or ARM/Thumb little endian only. Reviewers: javed.absar, rengolin, kristof.beyls, t.p.northover Reviewed By: rengolin Subscribers: llvm-commits, aemerson Differential Revision: https://reviews.llvm.org/D34682 llvm-svn: 310781
* 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
* 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
* Fix asm printing of associated sections.Evgeniy Stepanov2017-03-141-0/+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] Set SHT_MIPS_DWARF section type for all .debug_* sections on MIPSSimon Atanasyan2017-03-101-0/+4
| | | | | | | | | | | | All MIPS .debug_* sections should be marked with ELF type SHT_MIPS_DWARF accordingly the specification [1]. Also the same section type is assigned to these sections by GNU tools. [1] ftp.software.ibm.com/software/os390/czos/dwarf/mips_extensions.pdf Differential Revision: https://reviews.llvm.org/D29789 llvm-svn: 297447
* [MC] Accept a numeric value as an ELF section header's typeSimon Atanasyan2017-03-101-0/+4
| | | | | | | | | | | | | | | | | | | | | | 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
* [MC] Fix some Clang-tidy modernize and Include What You Use warnings; other ↵Eugene Zelenko2017-02-141-6/+4
| | | | | | | | minor fixes (NFC). Same changes in files affected by reduced MC headers dependencies. llvm-svn: 295009
* Only print architecture dependent flags for that architecture.Rafael Espindola2017-01-301-7/+12
| | | | | | | | | | Different architectures can have different meaning for flags in the SHF_MASKPROC mask, so we should always check what the architecture use before checking the flag. NFC for now, but will allow fixing the value of an xmos flag. llvm-svn: 293484
* [ARM] Implement execute-only support in CodeGenPrakhar Bahuguna2016-12-151-0/+2
| | | | | | | | | | | | | | | | | | | | 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
* Bring r252305 back with a test fix.Rafael Espindola2015-11-061-0/+2
| | | | | | | | | | We now create the .eh_frame section early, just like every other special section. This means that the special flags are visible in code that explicitly asks for ".eh_frame". llvm-svn: 252313
* MCAsmInfo: Allow targets to specify when the .section directive should be ↵Tom Stellard2015-09-251-6/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | omitted Summary: The default behavior is to omit the .section directive for .text, .data, and sometimes .bss, but some targets may want to omit this directive for other sections too. The AMDGPU backend will uses this to emit a simplified syntax for section switches. For example if the section directive is not omitted (current behavior), section switches to .hsatext will be printed like this: .section .hsatext,#alloc,#execinstr,#write This is actually wrong, because .hsatext has some custom STT_* flags, which MC doesn't know how to print or parse. If the section directive is omitted (made possible by this commit), section switches will be printed like this: .hsatext The motivation for this patch is to make it possible to emit sections with custom STT_* flags without having to teach MC about all the target specific STT_* flags. Reviewers: rafael, grosbach Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D12423 llvm-svn: 248618
* MC: Add target hook to control symbol quotingMatt Arsenault2015-06-091-4/+9
| | | | llvm-svn: 239370
* Use a comma after the unique keyword.Rafael Espindola2015-04-061-1/+1
| | | | | | | | H.J. Lu noted that all .section options are separated by a comma. This patch changes the syntax of unique to require one. llvm-svn: 234174
* Implement unique sections with an unique ID.Rafael Espindola2015-04-041-3/+3
| | | | | | | | | | | This allows the compiler/assembly programmer to switch back to a section. This in turn fixes the bootstrap failure on powerpc (tested on gcc110) without changing the ppc codegen at all. I will try to cleanup the various getELFSection overloads in a followup patch. Just using a default argument now would lead to ambiguities. llvm-svn: 234099
* Add r228980 back.Rafael Espindola2015-02-171-0/+7
| | | | | | | | | | Add support for having multiple sections with the same name and comdat. Using this in combination with -ffunction-sections allows LLVM to output a .o file with mulitple sections named .text. This saves space by avoiding long unique names of the form .text.<C++ mangled name>. llvm-svn: 229541
* Revert a series of commits starting at r228886 which is triggering someChandler Carruth2015-02-131-7/+0
| | | | | | | | | | | | | | | | regressions for LLDB on Linux. Rafael indicated on lldb-dev that we should just go ahead and revert these but that he wasn't at a computer. The patches backed out are as follows: r228980: Add support for having multiple sections with the name and ... r228889: Invert the section relocation map. r228888: Use the existing SymbolTableIndex intsead of doing a lookup. r228886: Create the Section -> Rel Section map when it is first needed. These patches look pretty nice to me, so hoping its not too hard to get them re-instated. =D llvm-svn: 229080
* Add support for having multiple sections with the same name and comdat.Rafael Espindola2015-02-121-0/+7
| | | | | | | | Using this in combination with -ffunction-sections allows LLVM to output a .o file with mulitple sections named .text. This saves space by avoiding long unique names of the form .text.<C++ mangled name>. llvm-svn: 228980
* Compute the ELF SectionKind from the flags.Rafael Espindola2015-01-291-10/+0
| | | | | | | | | | | | Any code creating an MCSectionELF knows ELF and already provides the flags. SectionKind is an abstraction used by common code that uses a plain MCSection. Use the flags to compute the SectionKind. This removes a lot of guessing and boilerplate from the MCSectionELF construction. llvm-svn: 227476
* delete function name from commentSanjay Patel2014-10-091-2/+2
| | | | llvm-svn: 219443
* Remove AllowQuotesInName and friends from MCAsmInfo.Rafael Espindola2013-11-131-23/+30
| | | | | | | | | | | Accepting quotes is a property of an assembler, not of an object file. For example, ELF can support any names for sections and symbols, but the gnu assembler only accepts quotes in some contexts and llvm-mc in a few more. LLVM should not produce different symbols based on a guess about which assembler will be reading the code it is printing. llvm-svn: 194575
* ELF: Add support for the exclude section bit for gas compat.Benjamin Kramer2013-09-151-0/+4
| | | | llvm-svn: 190769
* Add support for subsections to the ELF assembler. Fixes PR8717.Peter Collingbourne2013-04-171-2/+10
| | | | | | Differential Revision: http://llvm-reviews.chandlerc.com/D598 llvm-svn: 179725
* Tidy up. Trailing whitespace.Jim Grosbach2012-05-111-6/+6
| | | | llvm-svn: 156602
* Be nice to Xcore and the XMOS assembler and avoid quoting section namesJoerg Sonnenberger2011-03-041-12/+18
| | | | | | that contain only letters, digits and the characters "_" and ".". llvm-svn: 127028
* Bug#9033: For the ELF assembler output, always quote the section name.Joerg Sonnenberger2011-03-031-2/+16
| | | | llvm-svn: 126963
* Switch llvm to using comdats. For now always use groups with a singleRafael Espindola2011-02-141-0/+4
| | | | | | section. llvm-svn: 125526
* Move broken HasCommonSymbols to ELFWriter.cpp.Rafael Espindola2011-02-141-11/+0
| | | | llvm-svn: 125490
* Remove more duplicated code.Rafael Espindola2011-01-231-15/+15
| | | | llvm-svn: 124056
* Remove duplicated code.Rafael Espindola2011-01-231-7/+9
| | | | llvm-svn: 124054
* Add support for @note. Patch by Jörg Sonnenberger.Rafael Espindola2010-12-261-0/+2
| | | | llvm-svn: 122568
* make isVirtualSection a virtual method on MCSection. Chris' suggestion.Rafael Espindola2010-11-171-0/+4
| | | | llvm-svn: 119547
* Fixed version of 118639 with an extra assert to catch similar problemsRafael Espindola2010-11-091-32/+23
| | | | | | earlier. Implicit bool -> int conversions are evil! llvm-svn: 118651
* Revert previous patch. Missed a case.Rafael Espindola2010-11-091-22/+32
| | | | llvm-svn: 118645
* Remove IsExplicit. It was always false.Rafael Espindola2010-11-091-32/+22
| | | | llvm-svn: 118639
* Add hook in MCSection to decide when to use "optimized nops", for eachJan Wen Voung2010-10-041-0/+4
| | | | | | | section kind. Previously, optimized nops were only used for MachO. Also added tests for ELF and COFF. llvm-svn: 115523
* Move logic of determining ELF entsize from the .s printer to initializationJan Wen Voung2010-09-301-12/+11
| | | | | | | time. That way, the EntrySize field is initialized for other code paths, namely, the .ll -> .o code path. llvm-svn: 115141
* move elf section uniquing to MCContext. Along the wayChris Lattner2010-04-081-57/+57
| | | | | | merge XCore's section into MCSectionELF llvm-svn: 100812
* Simplify some uses of str(n)cmp with StringRef.Benjamin Kramer2010-01-221-7/+5
| | | | llvm-svn: 94189
* tidyChris Lattner2010-01-131-4/+3
| | | | llvm-svn: 93352
* Pass StringRef by value.Daniel Dunbar2009-11-061-1/+1
| | | | llvm-svn: 86251
* rename TAI -> MAI, being careful not to make MAILJMP instructions :)Chris Lattner2009-08-221-7/+7
| | | | llvm-svn: 79777
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