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* [WebAssembly] Add new `export_name` clang attribute for controlling wasm ↵Sam Clegg2019-12-111-0/+4
| | | | | | | | | | | | | | | | | | | | export names This is equivalent to the existing `import_name` and `import_module` attributes which control the import names in the final wasm binary produced by lld. This maps the existing This attribute currently requires a string rather than using the symbol name for a couple of reasons: 1. Avoid confusion with static and dynamic linking which is based on symbol name. Exporting a function from a wasm module using this directive is orthogonal to both static and dynamic linking. 2. Avoids name mangling. Differential Revision: https://reviews.llvm.org/D70520
* [WebAssembly][lld] Fix for static linking of PIC codeSam Clegg2019-10-291-2/+0
| | | | | | | | | | | When statically linking PIC code we create an internalized __memory_base so that memory-base-relative relocation work correctly. The value of this global should be zero, and not the globalBase since the globalBase offset is already taken into account by getVirtualAddress. Fixes: https://github.com/emscripten-core/emscripten/issues/9013 Differential Revision: https://reviews.llvm.org/D69600
* [WebAssembly] Elide data segments for .bss sectionsThomas Lively2019-10-151-1/+8
| | | | | | | | | | | | | | | | | | | Summary: WebAssembly memories are zero-initialized, so when module does not import its memory initializing .bss sections is guaranteed to be a no-op. To reduce binary size and initialization time, .bss sections are simply not emitted into the final binary unless the memory is imported. Reviewers: sbc100 Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D68965 llvm-svn: 374940
* [WebAssembly] Wrap definitions in namespace lld { namespace wasm {. NFCFangrui Song2019-10-101-3/+6
| | | | | | | | | | Similar to D68323, but for wasm. Reviewed By: ruiu Differential Revision: https://reviews.llvm.org/D68759 llvm-svn: 374279
* [lld][WebAssembly] Fix static linking of -fPIC code with external undefined ↵Sam Clegg2019-09-241-5/+5
| | | | | | | | functions Differential Revision: https://reviews.llvm.org/D66784 llvm-svn: 372779
* [WebAssembly][NFC] Remove unnecessary bracesThomas Lively2019-09-191-2/+1
| | | | llvm-svn: 372358
* [WebAssembly] Sort output data sections to place .bss lastThomas Lively2019-09-191-2/+19
| | | | | | | | | | | | | | | | | | | | Summary: This was always the intended behavior, but had not been implemented. This ordering is important for Emscripten when generating .mem files while compiling to JS, since only zeros at the end of initialized memory can be dropped. Fixes https://github.com/emscripten-core/emscripten/issues/8999 Reviewers: sbc100 Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D67736 llvm-svn: 372284
* [WebAssembly] Initialize memory in start functionThomas Lively2019-09-041-51/+144
| | | | | | | | | | | | | | | | | | | | | | | | | Summary: - `__wasm_init_memory` is now the WebAssembly start function instead of being called from `__wasm_call_ctors` or called directly by the runtime. - Adds a new synthetic data symbol `__wasm_init_memory_flag` that is atomically incremented from zero to one by the thread responsible for initializing memory. - All threads now unconditionally perform data.drop on all passive segments. - Removes --passive-segments and --active-segments flags and controls segment type based on --shared-memory instead. The deleted flags were only present to ameliorate the upgrade path in Emscripten. Reviewers: sbc100, aheejin Subscribers: dschuff, jgravelle-google, sunfish, jfb, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D65783 llvm-svn: 370965
* [lld][WebAssembly] Store table base in config rather than passing it around. ↵Sam Clegg2019-08-271-4/+3
| | | | | | | | | | | NFC. I've got another change that makes more use of this value in other places. Differential Revision: https://reviews.llvm.org/D66777 llvm-svn: 370010
* [lld][WebAssembly] Allow linking of pic code into static binariesSam Clegg2019-08-131-2/+9
| | | | | | | | | | | | Summary: See https://github.com/emscripten-core/emscripten/issues/9013 Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D65922 llvm-svn: 368719
* [WebAssembly] Fix null pointer in createInitTLSFunctionGuanzhong Chen2019-08-061-1/+1
| | | | | | | | | | | | | | | | | | | | | Summary: `createSyntheticSymbols`, which creates `WasmSym::InitTLS`, is only called when `!config->relocatable`, but this condition is not checked when calling `createInitTLSFunction`. This diff checks `!config->relocatable` before calling `createInitTLSFunction`. Fixes https://github.com/emscripten-core/emscripten/issues/9155. Reviewers: tlively, aheejin, kripken, sbc100 Subscribers: dschuff, jgravelle-google, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D65785 llvm-svn: 368078
* [WebAssembly] Compute and export TLS block alignmentGuanzhong Chen2019-07-191-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | Summary: Add immutable WASM global `__tls_align` which stores the alignment requirements of the TLS segment. Add `__builtin_wasm_tls_align()` intrinsic to get this alignment in Clang. The expected usage has now changed to: __wasm_init_tls(memalign(__builtin_wasm_tls_align(), __builtin_wasm_tls_size())); Reviewers: tlively, aheejin, sbc100, sunfish, alexcrichton Reviewed By: tlively Subscribers: dschuff, jgravelle-google, hiraditya, cfe-commits, llvm-commits Tags: #clang, #llvm Differential Revision: https://reviews.llvm.org/D65028 llvm-svn: 366624
* [WebAssembly] fix bug in finding .tdata segmentGuanzhong Chen2019-07-181-2/+3
| | | | | | | | | | | | | | | | Summary: Fix bug in `wasm-ld`'s `Writer::createInitTLSFunction` that only finds `.tdata` if it's the first section. Reviewers: tlively, aheejin, sbc100 Reviewed By: sbc100 Subscribers: dschuff, jgravelle-google, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D64947 llvm-svn: 366500
* [lld][WebAssembly] Fix handling of comdat functions in init array.Sam Clegg2019-07-171-0/+1
| | | | | | | | | | | | | | | | | When hidden symbols are discarded by comdat rules we still want to create a local defined symbol, otherwise `Symbol::isDiscarded()` relies on begin able to check `getChunk->discarded`. This is a followup on rL362769. The comdat.ll test was previously GC'ing the `__wasm_call_ctors` functions so `do_init` was not actually being included in the link. Once that function was included in triggered the crash bug that this change addresses. Fixes: https://github.com/emscripten-core/emscripten/issues/8981 Differential Revision: https://reviews.llvm.org/D64872 llvm-svn: 366358
* [WebAssembly] Implement thread-local storage (local-exec model)Guanzhong Chen2019-07-161-4/+77
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Thread local variables are placed inside a `.tdata` segment. Their symbols are offsets from the start of the segment. The address of a thread local variable is computed as `__tls_base` + the offset from the start of the segment. `.tdata` segment is a passive segment and `memory.init` is used once per thread to initialize the thread local storage. `__tls_base` is a wasm global. Since each thread has its own wasm instance, it is effectively thread local. Currently, `__tls_base` must be initialized at thread startup, and so cannot be used with dynamic libraries. `__tls_base` is to be initialized with a new linker-synthesized function, `__wasm_init_tls`, which takes as an argument a block of memory to use as the storage for thread locals. It then initializes the block of memory and sets `__tls_base`. As `__wasm_init_tls` will handle the memory initialization, the memory does not have to be zeroed. To help allocating memory for thread-local storage, a new compiler intrinsic is introduced: `__builtin_wasm_tls_size()`. This instrinsic function returns the size of the thread-local storage for the current function. The expected usage is to run something like the following upon thread startup: __wasm_init_tls(malloc(__builtin_wasm_tls_size())); Reviewers: tlively, aheejin, kripken, sbc100 Subscribers: dschuff, jgravelle-google, hiraditya, sunfish, jfb, cfe-commits, llvm-commits Tags: #clang, #llvm Differential Revision: https://reviews.llvm.org/D64537 llvm-svn: 366272
* [WebAssembly] Rename variale references in comments after VariableName -> ↵Fangrui Song2019-07-161-1/+1
| | | | | | variableName change llvm-svn: 366192
* [WebAssembly] i32.const operands should be signedThomas Lively2019-07-121-3/+3
| | | | | | | | | | | | | | | | Summary: This was causing large addresses to be emitted as negative numbers, which rightfully caused crashes in binaryen. Reviewers: aheejin, dschuff Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D64612 llvm-svn: 365930
* [WebAssembly] Import __stack_pointer when building -pie binariesSam Clegg2019-07-111-1/+1
| | | | | | | | | | | | | The -pie binary doesn't know that layout ahead of time so needs to import the stack pointer from the embedder, just like we do already for shared libraries. This change is needed in order to address: https://github.com/emscripten-core/emscripten/issues/8915 Differential Revision: https://reviews.llvm.org/D64516 llvm-svn: 365771
* [Coding style change][lld] Rename variables for non-ELF portsRui Ueyama2019-07-111-402/+402
| | | | | | | | | | | This patch does the same thing as r365595 to other subdirectories, which completes the naming style change for the entire lld directory. With this, the naming style conversion is complete for lld. Differential Revision: https://reviews.llvm.org/D64473 llvm-svn: 365730
* Make functions and member variables distinguishable even after the name ↵Rui Ueyama2019-07-101-10/+11
| | | | | | style change. NFC. llvm-svn: 365605
* [lld][WebAssembly] Report undefined symbols during scanRelocationsSam Clegg2019-07-091-7/+0
| | | | | | | | | | | | | | | | This puts handling of undefined symbols in a single location. Its also more in line with the ELF backend which only reports undefined symbols based on relocations. One side effect is that we no longer report undefined symbols that are only referenced in GC'd sections. This also fixes a crash reported in the emscripten toolchain: https://github.com/emscripten-core/emscripten/issues/8930. Differential Revision: https://reviews.llvm.org/D64280 llvm-svn: 365553
* [lld][WebAssembly] Fix name of data section in PIC modeSam Clegg2019-07-091-2/+2
| | | | | | | | | | This should always have been ".data". Without this we treat the section as a user-defined section in other places (such as the generation of __start/__stop symbols). Differential Revision: https://reviews.llvm.org/D64439 llvm-svn: 365547
* [lld][WebAssembly] Fix __start/__stop symbols when combining input segmentsSam Clegg2019-07-081-11/+9
| | | | | | | | | | | | We should be generating one __start/__stop pair per output segment not per input segment. The test wasn't catching this because it was only linking a single object file. Fixes PR41565 Differential Revision: https://reviews.llvm.org/D64148 llvm-svn: 365308
* [WebAssembly] Add option to emit passive segmentsThomas Lively2019-07-031-22/+69
| | | | | | | | | | | | | | | | | | | | | | | Summary: Adds `--passive-segments` and `--active-segments` flags to control what kind of segments are emitted. For now the default is always to emit active segments so this is not a breaking change, but in the future the default will be changed to passive segments when shared memory is requested and active segments otherwise. When passive segments are emitted, corresponding memory.init and data.drop instructions are emitted in a `__wasm_init_memory` function that is automatically called at the beginning of `__wasm_call_ctors`. Reviewers: sbc100, aheejin, dschuff Subscribers: azakai, dschuff, jgravelle-google, sunfish, jfb, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D59343 llvm-svn: 365088
* [wasm-ld] Add __global_base symbol to mark the value of --global-baseGuanzhong Chen2019-06-261-0/+3
| | | | | | | | | | | | | | | | | | | | | | Summary: This is needed for address sanitizer on Emscripten. As everything in memory starts at the value passed to --global-base, everything before that can be used as shadow memory. This symbol is added so that the library for the ASan runtime can know where the shadow memory ends and real memory begins. This is split from D63742. Reviewers: tlively, aheejin, sbc100 Subscribers: sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D63833 llvm-svn: 364467
* [WebAssembly] Fix for discarded init functionsSam Clegg2019-06-071-0/+3
| | | | | | | | | When a function is excluded via comdat we shouldn't add it to the final list of init functions. Differential Revision: https://reviews.llvm.org/D62983 llvm-svn: 362769
* [WebAssembly] Don't export __data_end and __heap_base by default.Sam Clegg2019-05-311-5/+4
| | | | | | | | These can still be exported via --export if needed. Differential Revision: https://reviews.llvm.org/D62744 llvm-svn: 362276
* [WebAssembly] Improve feature validation error messagesThomas Lively2019-05-301-20/+32
| | | | | | | | | | | | | | | | Summary: Add the names of the input files responsible for each error to the messages. Reviewers: sbc100, azakai Subscribers: dschuff, jgravelle-google, aheejin, sunfish, jfb, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D62704 llvm-svn: 362162
* [WebAssembly] Add support for -emit-relocsSam Clegg2019-05-241-5/+5
| | | | | | | | | | This can be useful for post-link tools and for testing. Sometimes it can be useful to produces a regular executable but with relocations preserved. Differential Revision: https://reviews.llvm.org/D62378 llvm-svn: 361635
* Reland: [WebAssembly] Add __start_/_stop_ symbols for data sectionsSam Clegg2019-05-231-4/+41
| | | | | | | | | | This is a reland of rL361235. Fixes https://bugs.llvm.org/show_bug.cgi?id=41565 Differential Revision: https://reviews.llvm.org/D61876 llvm-svn: 361476
* [WebAssembly] Seal imports section before counting importsSam Clegg2019-05-231-7/+9
| | | | | | | | | | | | | | | | | | | | | | | Summary: Before we can assign entries in the function of global index space we need to know the total number of function and global imports respectively. To avoid programmer error this change seals that imports section before assigned function and global index space. Any attempt to add an import after the section is sealed will assert. The lack this such as check caused https://reviews.llvm.org/D61876 to be reverted. I'm also trying to craft a test case the this failure. Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D62240 llvm-svn: 361470
* Revert "[WebAssembly] Add __start_/_stop_ symbols for data sections"Sam Clegg2019-05-211-43/+6
| | | | | | | | | This reverts commit 7804dbddccba412087a15cab8db4412939700952. This change broke a bunch of tests of the WebAssembly waterfall. Will hopefully reland with increased test coverage. llvm-svn: 361273
* [WebAssembly] Add __start_/_stop_ symbols for data sectionsSam Clegg2019-05-211-6/+43
| | | | | | | | Fixes https://bugs.llvm.org/show_bug.cgi?id=41565 Differential Revision: https://reviews.llvm.org/D61876 llvm-svn: 361236
* [WebAssembly] Refactor synthetic sections and relocation processing. NFC.Sam Clegg2019-05-211-847/+152
| | | | | | | | | | | Major refactor to better match the structure of the ELF linker. - Split out relocation processing into scanRelocations - Split out synthetic sections into their own classes. Differential Revision: https://reviews.llvm.org/D61811 llvm-svn: 361233
* [WebAssembly] Move code and data section generation to finalizeContent. NFC.Sam Clegg2019-05-161-5/+1
| | | | | | | | | | | | | | Previously these sections were being generated during their constructors. This moves the work to finalizeContent, and also does the same for the relocation sections because their contents depends on the final layout too. This change is part of a larger refactor to how we deal with synthetic sections: https://reviews.llvm.org/D61811 Differential Revision: https://reviews.llvm.org/D61971 llvm-svn: 360941
* [WebAssembly] Don't generate empty type sections.Sam Clegg2019-05-161-0/+2
| | | | | | Differential Revision: https://reviews.llvm.org/D61991 llvm-svn: 360940
* [WebAssembly] Refactor relocation processing. NFC.Sam Clegg2019-05-131-19/+17
| | | | | | | | | This is the remaining NFC part of https://reviews.llvm.org/D61539 which was reverted. Differential Revision: https://reviews.llvm.org/D61800 llvm-svn: 360598
* [WebAssembly] Don't assume that strongly defined symbols are DSO-localSam Clegg2019-05-101-3/+7
| | | | | | | | | | | | | | | | The current PIC model for WebAssembly is more like ELF in that it allows symbol interposition. This means that more functions end up being addressed via the GOT and fewer directly added to the wasm table. One effect is a reduction in the number of wasm table entries similar to the previous attempt in https://reviews.llvm.org/D61539 which was reverted. Differential Revision: https://reviews.llvm.org/D61772 llvm-svn: 360402
* Revert "[WebAssembly] Don't generate unused table entries."Sam Clegg2019-05-091-20/+20
| | | | | | | | This reverts commit b33fdb7768e5de5fbeb23f65d8d455e7ca88b021. This change apparently broke am emscripten test. llvm-svn: 360367
* [WebAssembly] Don't generate unused table entries.Sam Clegg2019-05-071-20/+20
| | | | | | | | | | | | | | When generating PIC output only relocations of type R_WASM_TABLE_INDEX_REL_SLEB should generate table entries. R_WASM_TABLE_INDEX_I32 get resolved at runtime via the auto-generated __wasm_apply_relocs functions. R_WASM_TABLE_INDEX_SLEB are not allowed in PIC code. Differential Revision: https://reviews.llvm.org/D61539 llvm-svn: 360165
* Use llvm::stable_sortFangrui Song2019-04-231-4/+4
| | | | | | | | | Make some small adjustment while touching the code: make parameters const, use less_first(), etc. Differential Revision: https://reviews.llvm.org/D60989 llvm-svn: 358943
* [WebAssembly] Error on relocations against undefined data symbols.Sam Clegg2019-04-221-0/+14
| | | | | | | | | | | | | | | | | We can't (currently) meaningfully resolve certain types of relocations against undefined data symbols. Previously when `--allow-undefined` was used we were treating such relocation much like weak data symbols and simply inserting zeros. This change turns such use cases in to an error. This means that `--allow-undefined` is no longer effective for data symbols. Fixes https://bugs.llvm.org/show_bug.cgi?id=40364 Differential Revision: https://reviews.llvm.org/D60882 llvm-svn: 358899
* [WebAssembly] Emit the DataCount section when bulk memory is enabledThomas Lively2019-04-191-0/+12
| | | | | | | | | | | | | | | | | | Summary: The DataCount section is necessary for the bulk memory operations memory.init and data.drop to validate, but it is not recognized by engines that do not support bulk memory, so emit the section only if bulk-memory is enabled. Reviewers: aheejin, dschuff, sbc100 Subscribers: jgravelle-google, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D60637 llvm-svn: 358798
* [wasm] Simplify. NFCFangrui Song2019-04-181-2/+2
| | | | llvm-svn: 358663
* [WebAssembly] Assign GOT entries symbols used in data relocationsSam Clegg2019-04-101-3/+14
| | | | | | Differential Revision: https://reviews.llvm.org/D60492 llvm-svn: 358090
* [WebAssembly] Include function in wasm table when used in ↵Sam Clegg2019-04-051-1/+2
| | | | | | | | | | | | R_WASM_TABLE_INDEX_REL_SLEB This should have been part of rL357710 but was overlooked because in our test code the function in question was also used in other relocations that caused it to be added to the table anyway. Differential Revision: https://reviews.llvm.org/D60296 llvm-svn: 357737
* [WebAssembly] Apply data relocations at runtime in shared objectsSam Clegg2019-04-041-19/+61
| | | | | | | | | | | | | See: https://github.com/WebAssembly/tool-conventions/blob/master/DynamicLinking.md Data section relocations in wasm shared libraries are applied by the library itself at static constructor time. This change adds a new synthetic function that applies relocations to relevant memory locations on startup. Differential Revision: https://reviews.llvm.org/D59278 llvm-svn: 357715
* Re-land "[WebAssembly] Improve invalid relocation error message""Sam Clegg2019-03-291-7/+6
| | | | | | | | | | See https://reviews.llvm.org/D59860 The initial version of this change effected more than just the error message. This version is scoped down to only effect the error itself. llvm-svn: 357328
* [WebAssembly] "atomics" feature requires shared memoryThomas Lively2019-03-291-3/+11
| | | | | | | | | | | | | | | | | | Summary: Makes it a linker error if the "atomics" feature is used but the user does not opt in to shared memory or if "atomics" is disallowed but the user does opt in to shared memory. Also check that an appropriate max memory size is supplied if shared memory is used. Reviewers: sbc100, aheejin Subscribers: dschuff, jgravelle-google, sunfish, jfb, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D59281 llvm-svn: 357310
* [ELF][MachO][wasm] Simplify range-style std::find{,_if} with STLExtras.h ↵Fangrui Song2019-03-291-4/+4
| | | | | | utilities. NFC llvm-svn: 357269
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