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path: root/llvm/lib/Target/WebAssembly/WebAssemblyEHRestoreStackPointer.cpp
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* [WebAssembly] Restore stack pointer right after catch instructionHeejin Ahn2019-01-301-86/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: After the staack is unwound due to a thrown exxception, `__stack_pointer` global can point to an invalid address. So a `global.set` to restore `__stack_pointer` should be inserted right after `catch` instruction. But after r352598 the `global.set` instruction is inserted not right after `catch` but after `block` - `br-on-exn` - `end_block` - `extract_exception` sequence. This CL fixes it. While doing that, we can actually move ReplacePhysRegs pass after LateEHPrepare and merge EHRestoreStackPointer pass into LateEHPrepare, and now placing `global.set` to `__stack_pointer` right after `catch` is much easier. Otherwise it is hard to guarantee that `global.set` is still right after `catch` and not touched with other transformations, in which case we have to do something to hoist it. Reviewers: dschuff Subscribers: mgorny, sbc100, jgravelle-google, sunfish, llvm-commits Differential Revision: https://reviews.llvm.org/D57421 llvm-svn: 352681
* [WebAssembly] Exception handling: Switch to the new proposalHeejin Ahn2019-01-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This switches the EH implementation to the new proposal: https://github.com/WebAssembly/exception-handling/blob/master/proposals/Exceptions.md (The previous proposal was https://github.com/WebAssembly/exception-handling/blob/master/proposals/old/Exceptions.md) - Instruction changes - Now we have one single `catch` instruction that returns a except_ref value - `throw` now can take variable number of operations - `rethrow` does not have 'depth' argument anymore - `br_on_exn` queries an except_ref to see if it matches the tag and branches to the given label if true. - `extract_exception` is a pseudo instruction that simulates popping values from wasm stack. This is to make `br_on_exn`, a very special instruction, work: `br_on_exn` puts values onto the stack only if it is taken, and the # of values can vay depending on the tag. - Now there's only one `catch` per `try`, this patch removes all special handling for terminate pad with a call to `__clang_call_terminate`. Before it was the only case there are two catch clauses (a normal `catch` and `catch_all` per `try`). - Make `rethrow` act as a terminator like `throw`. This splits BB after `rethrow` in WasmEHPrepare, and deletes an unnecessary `unreachable` after `rethrow` in LateEHPrepare. - Now we stop at all catchpads (because we add wasm `catch` instruction that catches all exceptions), this creates new `findWasmUnwindDestinations` function in SelectionDAGBuilder. - Now we use `br_on_exn` instrution to figure out if an except_ref matches the current tag or not, LateEHPrepare generates this sequence for catch pads: ``` catch block i32 br_on_exn $__cpp_exception end_block extract_exception ``` - Branch analysis for `br_on_exn` in WebAssemblyInstrInfo - Other various misc. changes to switch to the new proposal. Reviewers: dschuff Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits Differential Revision: https://reviews.llvm.org/D57134 llvm-svn: 352598
* 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
* [WebAssembly] Print a debug message at the start of each passHeejin Ahn2019-01-091-0/+4
| | | | | | | | | | | | | | | Summary: Looks like many passes print its pass description as a debug message at the start of each pass, so added that to (mostly newly added) other passes as well. Reviewers: dschuff Subscribers: jgravelle-google, sbc100, sunfish, llvm-commits Differential Revision: https://reviews.llvm.org/D56142 llvm-svn: 350771
* [WebAssembly] Don't write SP back when prolog is generated only for EHHeejin Ahn2018-08-221-0/+5
| | | | | | | | | | | | | | | Summary: When we don't actually have stack-allocated variables but need SP only to support EH, we don't need to write SP back in the epilog, because we don't bump down the stack pointer. Reviewers: dschuff Subscribers: jgravelle-google, sbc100, sunfish, llvm-commits Differential Revision: https://reviews.llvm.org/D51114 llvm-svn: 340454
* [WebAssembly] Restore __stack_pointer after catch instructionsHeejin Ahn2018-08-211-0/+78
Summary: After the stack is unwound due to a thrown exception, the `__stack_pointer` global can point to an invalid address. This inserts instructions that restore `__stack_pointer` global. Reviewers: jgravelle-google, dschuff Subscribers: mgorny, sbc100, sunfish, llvm-commits Differential Revision: https://reviews.llvm.org/D50980 llvm-svn: 340339
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