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| author | Derek Schuff <dschuff@chromium.org> | 2015-11-06 13:34:57 -0800 |
|---|---|---|
| committer | Derek Schuff <dschuff@chromium.org> | 2015-11-06 13:34:57 -0800 |
| commit | 9f4f1300d48b93ba43ca2c228f8e55b271f0fddf (patch) | |
| tree | 38fa477f51557766cbd8cd972f1061412d5de09c | |
| parent | ec4d60ee891444d7dcf6766af827d425f3358f03 (diff) | |
| parent | ed646c9c0914adb64149b0b71e5d91f995696a22 (diff) | |
| download | nanowasm-design-9f4f1300d48b93ba43ca2c228f8e55b271f0fddf.tar.gz | |
Merge pull request #454 from WebAssembly/unreachable
Add unconditional unreachable instruction
| -rw-r--r-- | AstSemantics.md | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/AstSemantics.md b/AstSemantics.md index d1a0779..9aebc25 100644 --- a/AstSemantics.md +++ b/AstSemantics.md @@ -540,3 +540,13 @@ returning the same value for the same string over the lifetime of a single instance and other related (as defined by the host environment) instances. See also [feature testing](FeatureTest.md) and [better feature testing](FutureFeatures.md#better-feature-testing-support). + +## Unreachable + + * `unreachable`: An expression which can take on any type, and which, if + executed, always traps. It is intended to be used for example after + calls to functions which are known by the producer not to return (otherwise + the producer would have to create another expression with an unused value + to satisfy the type check). This trap is intended to be impossible for user + code to catch or handle, even in the future when it may be possible to + handle some other kinds of traps or exceptions. |