From e2f49d8227f2b71e4dede5cf4074bb9f65e3d77f Mon Sep 17 00:00:00 2001 From: Heejin Ahn Date: Tue, 13 Aug 2019 00:29:26 +0900 Subject: Add basic exception handling support (#2282) This adds basic support for exception handling instructions, according to the spec: https://github.com/WebAssembly/exception-handling/blob/master/proposals/Exceptions.md This PR includes support for: - Binary reading/writing - Wast reading/writing - Stack IR - Validation - binaryen.js + C API - Few IR routines: branch-utils, type-updating, etc - Few passes: just enough to make `wasm-opt -O` pass - Tests This PR does not include support for many optimization passes, fuzzer, or interpreter. They will be follow-up PRs. Try-catch construct is modeled in Binaryen IR in a similar manner to that of if-else: each of try body and catch body will contain a block, which can be omitted if there is only a single instruction. This block will not be emitted in wast or binary, as in if-else. As in if-else, `class Try` contains two expressions each for try body and catch body, and `catch` is not modeled as an instruction. `exnref` value pushed by `catch` is get by `pop` instruction. `br_on_exn` is special: it returns different types of values when taken and not taken. We make `exnref`, the type `br_on_exn` pushes if not taken, as `br_on_exn`'s type. --- test/exception-handling.wast.from-wast | 42 +++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) (limited to 'test/exception-handling.wast.from-wast') diff --git a/test/exception-handling.wast.from-wast b/test/exception-handling.wast.from-wast index cc4d5a1a0..7c431a89f 100644 --- a/test/exception-handling.wast.from-wast +++ b/test/exception-handling.wast.from-wast @@ -1,7 +1,47 @@ (module (type $FUNCSIG$ee (func (param exnref) (result exnref))) - (memory $0 1 1) + (type $FUNCSIG$v (func)) + (type $FUNCSIG$vi (func (param i32))) + (event $e0 (attr 0) (param i32)) (func $exnref_test (; 0 ;) (type $FUNCSIG$ee) (param $0 exnref) (result exnref) (local.get $0) ) + (func $eh_test (; 1 ;) (type $FUNCSIG$v) + (local $exn exnref) + (try + (throw $e0 + (i32.const 0) + ) + (catch + (local.set $exn + (exnref.pop) + ) + (drop + (block $l0 (result i32) + (rethrow + (br_on_exn $l0 $e0 + (local.get $exn) + ) + ) + ) + ) + ) + ) + (block $l1 + (try + (br $l1) + (catch + (br $l1) + ) + ) + ) + (try + (nop) + (catch + (drop + (exnref.pop) + ) + ) + ) + ) ) -- cgit v1.2.3