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path: root/lib/MC/ELFObjectWriter.cpp
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* Convert some assert(0) to llvm_unreachable or fold an 'if' condition into ↵Craig Topper2014-06-19
| | | | | | the assert. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211254 91177308-0d34-0410-b5e6-96231b3b80d8
* Using llvm::sys::swapByteOrder() for the common case of byte-swapping a ↵Artyom Skrobov2014-06-14
| | | | | | value in place git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210978 91177308-0d34-0410-b5e6-96231b3b80d8
* Renaming SwapByteOrder() to getSwappedBytes()Artyom Skrobov2014-06-14
| | | | | | | | The next commit will add swapByteOrder(), acting in-place git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210973 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix pr19645.Rafael Espindola2014-05-03
| | | | | | | | | | | | | | | | The fix itself is fairly simple: move getAccessVariant to MCValue so that we replace the old weak expression evaluation with the far more general EvaluateAsRelocatable. This then requires that EvaluateAsRelocatable stop when it finds a non trivial reference kind. And that in turn requires the ELF writer to look harder for weak references. Last but not least, this found a case where we were being bug by bug compatible with gas and accepting an invalid input. I reported pr19647 to track it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207920 91177308-0d34-0410-b5e6-96231b3b80d8
* Move getBaseSymbol somewhere the COFF writer can use.Rafael Espindola2014-05-01
| | | | | | I will use it there in a second. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207761 91177308-0d34-0410-b5e6-96231b3b80d8
* Make getBaseSymbol non recursive.Rafael Espindola2014-05-01
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207759 91177308-0d34-0410-b5e6-96231b3b80d8
* Provide a version of getSymbolOffset that returns false on error.Rafael Espindola2014-04-30
| | | | | | | This simplifies ELFObjectWriter::SymbolValue a bit more. This new version will also be used in the COFF writer to fix pr19147. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207711 91177308-0d34-0410-b5e6-96231b3b80d8
* Simplify ELFObjectWriter::SymbolValue.Rafael Espindola2014-04-30
| | | | | | It now defers all offset computation to getSymbolOffset. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207674 91177308-0d34-0410-b5e6-96231b3b80d8
* ELFObjectWriter: deduplicate suffices in strtabHans Wennborg2014-04-30
| | | | | | | | | | | | | | | We already do this for shstrtab, so might as well do it for strtab. This extracts the string table building code into a separate class. The idea is to use it for other object formats too. I mostly wanted to do this for the general principle, but it does save a little bit on object file size. I tried this on a clang bootstrap and saved 0.54% on the sum of object file sizes (1.14 MB out of 212 MB for a release build). Differential Revision: http://reviews.llvm.org/D3533 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207670 91177308-0d34-0410-b5e6-96231b3b80d8
* Centralize the handling of the thumb bit.Rafael Espindola2014-04-29
| | | | | | | | | | | | | This patch centralizes the handling of the thumb bit around MCStreamer::isThumbFunc and makes isThumbFunc handle aliases. This fixes a corner case, but the main advantage is having just one way to check if a MCSymbol is thumb or not. This should still be refactored to be ARM only, but at least now it is just one predicate that has to be refactored instead of 3 (isThumbFunc, ELF_Other_ThumbFunc, and SF_ThumbFunc). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207522 91177308-0d34-0410-b5e6-96231b3b80d8
* Add an option for evaluating past symbols.Rafael Espindola2014-04-28
| | | | | | | | | | | | | When evaluating an assembly expression for a relocation, we want to stop at MCSymbols that are in the symbol table, even if they are variables. This is needed since the semantics may require that the relocation use them. That is not the case when computing the value of a symbol in the symbol table. There are no relocations in this case and we have to keep going until we hit a section or find out that the expression doesn't have an assembly time value. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207445 91177308-0d34-0410-b5e6-96231b3b80d8
* Simplify ELFObjectWriter::ExecutePostLayoutBinding.Rafael Espindola2014-04-28
| | | | | | | No functionality change. This removes the last use of AliasedSymbol in ELFObjectWriter.cpp. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207424 91177308-0d34-0410-b5e6-96231b3b80d8
* Simplify isLocal().Rafael Espindola2014-04-28
| | | | | | No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207421 91177308-0d34-0410-b5e6-96231b3b80d8
* Don't include an invalid symbol in the symbol table.Rafael Espindola2014-04-28
| | | | | | | | | | | | The symbol table itself has no relocations, so it is not possible to represent things like a = undefined + 1 With the patch we just omit these variables. That matches the behaviour of the gnu assembler. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207419 91177308-0d34-0410-b5e6-96231b3b80d8
* Produce an error instead of a crash in an expr we cannot represent.Rafael Espindola2014-04-28
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207414 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix quadratic performance during debug compression due to sections x symbols ↵David Blaikie2014-04-25
| | | | | | | | | | | | | | | | iteration. When fixing the symbols in each compressed section we were iterating over all symbols for each compressed section. In extreme cases this could snowball severely (5min uncompressed -> 35min compressed) due to iterating over all symbols for each compressed section (large numbers of compressed sections can be generated by DWARF type units). To address this, build a map of the symbols in each section ahead of time, and access that map if a section is being compressed. This brings compile time for the aforementioned example down to ~6 minutes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207167 91177308-0d34-0410-b5e6-96231b3b80d8
* Spread some const around for non-mutating uses of MCSymbolData.David Blaikie2014-04-24
| | | | | | | | I discovered this const-hole while attempting to coalesnce the Symbol and SymbolMap data structures. There's some pending issues with that, but I figured this change was easy to flush early. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207124 91177308-0d34-0410-b5e6-96231b3b80d8
* Centralize handling of ELF_Other_ThumbFunc.Rafael Espindola2014-04-23
| | | | | | No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206988 91177308-0d34-0410-b5e6-96231b3b80d8
* Follow aliases when determining if a symbol is thumb.Rafael Espindola2014-04-22
| | | | | | This fixes pr19484. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206917 91177308-0d34-0410-b5e6-96231b3b80d8
* Add parens to appease GCC warning.David Blaikie2014-04-19
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206678 91177308-0d34-0410-b5e6-96231b3b80d8
* Compress debug sections only when beneficial.David Blaikie2014-04-18
| | | | | | | | | Both ZLIB and the debug info compressed section header ("ZLIB" + the size of the uncompressed data) take some constant overhead so in some cases the compressed data is actually larger than the uncompressed data. In these cases, just don't compress or rename the section at all. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206659 91177308-0d34-0410-b5e6-96231b3b80d8
* Update the fragments of symbols in compressed sections.David Blaikie2014-04-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While unnamed relocations are already cached in side tables in ELFObjectWriter::RecordRelocation, symbols still need their fragments updated to refer to the newly compressed fragment (even if that fragment isn't big enough to fit the offset). Even though we only create temporary symbols in debug info sections this comes up in 32 bit builds where even temporary symbols in mergeable sections (such as debug_str) have to be emitted as named symbols. I tried a few other ways to do this but they all didn't work for various reasons: 1) Canonicalize the MCSymbolData in RecordRelocation, nulling out the Fragment (so it didn't have to be updated by CompressDebugSection). This doesn't work because some code relies on symbols having fragments to indicate that they're defined, I think. 2) Canonicalize the MCSymbolData in RecordRelocation to be "first fragment + absolute offset" so it would be cheaper to just test and update the fragment in CompressDebugSections. This doesn't work because the offset computed in RecordRelocation isn't that of the symbol's fragment, it's the passed in fragment (I haven't figured out what that fragment is - perhaps it's the location where the relocation is to be written). And if the fragment offset has to be computed only for this use we might as well just do it when we need to, in CompressDebugSection. I also added an assert to help catch this a bit more clearly, even though it is UB. The test case improvements would either assert fail and/or valgrind vail without the fix, even if they wouldn't necessarily fail the FileCheck output. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206653 91177308-0d34-0410-b5e6-96231b3b80d8
* Add range access to MCAssembler's symbol collection.David Blaikie2014-04-18
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206631 91177308-0d34-0410-b5e6-96231b3b80d8
* [C++11] More 'nullptr' conversion or in some cases just using a boolean ↵Craig Topper2014-04-13
| | | | | | check instead of comparing to nullptr. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206129 91177308-0d34-0410-b5e6-96231b3b80d8
* Format fixes for r205990David Blaikie2014-04-11
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206078 91177308-0d34-0410-b5e6-96231b3b80d8
* Don't lose the thumb bit by using relocations with sections.Rafael Espindola2014-04-11
| | | | | | This fixes a regression from r205076. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206047 91177308-0d34-0410-b5e6-96231b3b80d8
* Reimplement debug info compression by compressing the whole section, rather ↵David Blaikie2014-04-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | than a fragment. To support compressing the debug_line section that contains multiple fragments (due, I believe, to variation in choices of line table encoding depending on the size of instruction ranges in the actual program code) we needed to support compressing multiple MCFragments in a single pass. This patch implements that behavior by mutating the post-relaxed and relocated section to be the compressed form of its former self, including renaming the section. This is a more flexible (and less invasive, to a degree) implementation that will allow for other features such as "use compression only if it's smaller than the uncompressed data". Compressing debug_frame would be a possible further extension to this work, but I've left it for now. The hurdle there is alignment sections - which might require going as far as to refactor MCAssembler.cpp:writeFragment to handle writing to a byte buffer or an MCObjectWriter (there's already a virtual call there, so it shouldn't add substantial compile-time cost) which could in turn involve refactoring MCAsmBackend::writeNopData to use that same abstraction... which involves touching all the backends. This would remove the limited handling of fragment writing seen in ELFObjectWriter.cpp:getUncompressedData which would be nice - but it's more invasive. I did discover that I (perhaps obviously) don't need to handle relocations when I rewrite the fragments - since the relocations have already been applied and computed (and stored into ELFObjectWriter::Relocations) by this stage (necessarily, because we need to have written any immediate values or assembly-time relocations into the data already before we compress it, which we have). The test case doesn't necessarily cover that in detail - I can add more test coverage if that's preferred. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205990 91177308-0d34-0410-b5e6-96231b3b80d8
* Work around gold bug http://sourceware.org/PR16794.Rafael Espindola2014-04-02
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205416 91177308-0d34-0410-b5e6-96231b3b80d8
* Completely rewrite ELFObjectWriter::RecordRelocation.Rafael Espindola2014-03-29
| | | | | | | | | | | | | | | | | | | I started trying to fix a small issue, but this code has seen a small fix too many. The old code was fairly convoluted. Some of the issues it had: * It failed to check if a symbol difference was in the some section when converting a relocation to pcrel. * It failed to check if the relocation was already pcrel. * The pcrel value computation was wrong in some cases (relocation-pc.s) * It was missing quiet a few cases where it should not convert symbol relocations to section relocations, leaving the backends to patch it up. * It would not propagate the fact that it had changed a relocation to pcrel, requiring a quiet nasty work around in ARM. * It was missing comments. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205076 91177308-0d34-0410-b5e6-96231b3b80d8
* Remove another unused argument.Rafael Espindola2014-03-27
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204961 91177308-0d34-0410-b5e6-96231b3b80d8
* Remove unused argument.Rafael Espindola2014-03-27
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204956 91177308-0d34-0410-b5e6-96231b3b80d8
* Correctly propagates st_size.Rafael Espindola2014-03-27
| | | | | | This also finally removes a bogus call to AliasedSymbol. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204883 91177308-0d34-0410-b5e6-96231b3b80d8
* Correctly detect if a symbol uses a reserved section index or not.Rafael Espindola2014-03-26
| | | | | | | The logic was incorrect for variables, causing them to end up in the wrong section if the section had an index >= 0xff00. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204771 91177308-0d34-0410-b5e6-96231b3b80d8
* Create .symtab_shndxr only when needed.Rafael Espindola2014-03-25
| | | | | | | | | | | | | | | | | | | | | | | We need .symtab_shndxr if and only if a symbol references a section with an index >= 0xff00. The old code was trying to figure out if the section was needed ahead of time, making it a fairly dependent on the code actually writing the table. It was also somewhat conservative and would create the section in cases where it was not needed. If I remember correctly, the old structure was there so that the sections were created in the same order gas creates them. That was valuable when MC's support for ELF was new and we tested with elf-dump.py. This patch refactors the symbol table creation to another class and makes it obvious that .symtab_shndxr is really only created when we are about to output a reference to a section index >= 0xff00. While here, also improve the tests to use macros. One file is one section short of needing .symtab_shndxr, the second one has just the right number. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204769 91177308-0d34-0410-b5e6-96231b3b80d8
* Use Endian.h to simplify this code a bit.Rafael Espindola2014-03-25
| | | | | | | While at it, factor some logic into FragmentWriter. This will allow more code to be factored out of the fairly large ELFObjectWriter. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204765 91177308-0d34-0410-b5e6-96231b3b80d8
* Propagate section from base to derived symbol.Rafael Espindola2014-03-24
| | | | | | | | | | | | We were already propagating the section in a = b With this patch we also propagate it for a = b + 1 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204581 91177308-0d34-0410-b5e6-96231b3b80d8
* Propagate types from symbol to aliases.Rafael Espindola2014-03-23
| | | | | | | | | | | | | | | | | | | | | | | This is similar, but not identical to what gas does. The logic in MC is to just compute the symbol table after parsing the entire file. GAS is mixed, given .type b, @object a = b b: .type b, @function It will propagate the change and make 'a' a function. Given .type b, @object b: a = b .type b, @function the type of 'a' is still object. Since we do the computation in the end, we produce a function in both cases. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204555 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix the value computation inRafael Espindola2014-03-21
| | | | | | | | | | sym_a: sym_d = sym_a + 1 This is the smallest fix I was able to extract from what got reverted in r204203. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204527 91177308-0d34-0410-b5e6-96231b3b80d8
* Reapply 'ARM IAS: support .thumb_set'Saleem Abdulrasool2014-03-20
| | | | | | | Re-apply the change after it was reverted to do conflicts due to another change being reverted. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204306 91177308-0d34-0410-b5e6-96231b3b80d8
* Look through variables when computing relocations.Rafael Espindola2014-03-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Given bar = foo + 4 .long bar MC would eat the 4. GNU as includes it in the relocation. The rule seems to be that a variable that defines a symbol is used in the relocation and one that does not define a symbol is evaluated and the result included in the relocation. Fixing this unfortunately required some other changes: * Since the variable is now evaluated, it would prevent the ELF writer from noticing the weakref marker the elf streamer uses. This patch then replaces that with a VariantKind in MCSymbolRefExpr. * Using VariantKind then requires us to look past other VariantKind to see .weakref bar,foo call bar@PLT doing this also fixes zed = foo +2 call zed@PLT so that is a good thing. * Looking past VariantKind means that the relocation selection has to use the fixup instead of the target. This is a reboot of the previous fixes for MC. I will watch the sanitizer buildbot and wait for a build before adding back the previous fixes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204294 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert "Add back r203962, r204028 and r204059."Rafael Espindola2014-03-19
| | | | | | This reverts commit r204178. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204203 91177308-0d34-0410-b5e6-96231b3b80d8
* Add back r203962, r204028 and r204059.Rafael Espindola2014-03-18
| | | | | | | | This reverts commit r204137. This includes a fix for handling aliases of aliases. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204178 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert r203962 and two revisions depending on it: r204028 and r204059.Alexander Kornienko2014-03-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The revision I'm reverting breaks handling of transitive aliases. This blocks us and breaks sanitizer bootstrap: http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/2651 (and checked locally by Alexey). This revision is the result of: svn merge -r204059:204058 -r204028:204027 -r203962:203961 . + the regression test added to test/MC/ELF/alias.s Another way to reproduce the regression with clang: $ cat q.c void a1(); void a2() __attribute__((alias("a1"))); void a3() __attribute__((alias("a2"))); void a1() {} $ ~/work/llvm-build/bin/clang-3.5-good -c q.c && mv q.o good.o && \ ~/work/llvm-build/bin/clang-3.5-bad -c q.c && mv q.o bad.o && \ objdump -t good.o bad.o good.o: file format elf64-x86-64 SYMBOL TABLE: 0000000000000000 l df *ABS* 0000000000000000 q.c 0000000000000000 l d .text 0000000000000000 .text 0000000000000000 l d .data 0000000000000000 .data 0000000000000000 l d .bss 0000000000000000 .bss 0000000000000000 l d .comment 0000000000000000 .comment 0000000000000000 l d .note.GNU-stack 0000000000000000 .note.GNU-stack 0000000000000000 l d .eh_frame 0000000000000000 .eh_frame 0000000000000000 g F .text 0000000000000006 a1 0000000000000000 g F .text 0000000000000006 a2 0000000000000000 g F .text 0000000000000006 a3 bad.o: file format elf64-x86-64 SYMBOL TABLE: 0000000000000000 l df *ABS* 0000000000000000 q.c 0000000000000000 l d .text 0000000000000000 .text 0000000000000000 l d .data 0000000000000000 .data 0000000000000000 l d .bss 0000000000000000 .bss 0000000000000000 l d .comment 0000000000000000 .comment 0000000000000000 l d .note.GNU-stack 0000000000000000 .note.GNU-stack 0000000000000000 l d .eh_frame 0000000000000000 .eh_frame 0000000000000000 g F .text 0000000000000006 a1 0000000000000000 g F .text 0000000000000006 a2 0000000000000000 g .text 0000000000000000 a3 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204137 91177308-0d34-0410-b5e6-96231b3b80d8
* ARM IAS: support .thumb_setSaleem Abdulrasool2014-03-17
| | | | | | | | | | | | | | This performs the equivalent of a .set directive in that it creates a symbol which is an alias for another symbol or value which may possibly be yet undefined. This directive also has the added property in that it marks the aliased symbol as being a thumb function entry point, in the same way that the .thumb_func directive does. The current implementation fails one test due to an unrelated issue. Functions within .thumb sections are not marked as thumb_func. The result is that the aliasee function is not valued correctly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204059 91177308-0d34-0410-b5e6-96231b3b80d8
* Consider the base pointer for setting the symbol type.Rafael Espindola2014-03-17
| | | | | | | | | | | | | | This is really a consistency fix. Since given a = b we propagate the information, we should propagate it too given a = b + (1 - 1) Fixes pr19145. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204028 91177308-0d34-0410-b5e6-96231b3b80d8
* Correctly handle an ELF symbol defined with "a = b + expr".Rafael Espindola2014-03-14
| | | | | | | | | We were marking the symbol as absolute instead of computing b's offset + the expression value. This fixes pr19126. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203962 91177308-0d34-0410-b5e6-96231b3b80d8
* [C++11] Add 'override' keyword to virtual methods that override their base ↵Craig Topper2014-03-08
| | | | | | class. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203340 91177308-0d34-0410-b5e6-96231b3b80d8
* Replace OwningPtr<T> with std::unique_ptr<T>.Ahmed Charles2014-03-06
| | | | | | | | | | This compiles with no changes to clang/lld/lldb with MSVC and includes overloads to various functions which are used by those projects and llvm which have OwningPtr's as parameters. This should allow out of tree projects some time to move. There are also no changes to libs/Target, which should help out of tree targets have time to move, if necessary. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203083 91177308-0d34-0410-b5e6-96231b3b80d8
* doesSectionRequireSymbols is meaningless on ELF, remove.Rafael Espindola2014-02-06
| | | | | | | | | | | | | | | | | | | | This is a nop. doesSectionRequireSymbols is only used from isSymbolLinkerVisible. isSymbolLinkerVisible only use from ELF was in if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined()) return false; if (Symbol.isTemporary()) return false; If the symbol is a temporary this code returns false and it is irrelevant if we take the first if or not. If the symbol is not a temporary, Asm.isSymbolLinkerVisible returns true without ever calling doesSectionRequireSymbols. This was an horrible leftover from when support for ELF was first added. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200894 91177308-0d34-0410-b5e6-96231b3b80d8
* Force emit a relocation for @gnu_indirect_function symbols so that the indirectRoman Divacky2014-01-08
| | | | | | | resolution works. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198780 91177308-0d34-0410-b5e6-96231b3b80d8
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