diff options
Diffstat (limited to 'src/passes/LocalSubtyping.cpp')
| -rw-r--r-- | src/passes/LocalSubtyping.cpp | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/src/passes/LocalSubtyping.cpp b/src/passes/LocalSubtyping.cpp index 19ce2f275..24a2e48e4 100644 --- a/src/passes/LocalSubtyping.cpp +++ b/src/passes/LocalSubtyping.cpp @@ -27,6 +27,7 @@ #include <ir/local-graph.h> #include <ir/utils.h> #include <pass.h> +#include <wasm-builder.h> #include <wasm.h> namespace wasm { @@ -178,10 +179,36 @@ struct LocalSubtyping : public WalkerPass<PostWalker<LocalSubtyping>> { get->type = func->getLocalType(get->index); } for (auto* set : FindAll<LocalSet>(func->body).list) { + auto newType = func->getLocalType(set->index); if (set->isTee()) { - set->type = func->getLocalType(set->index); + set->type = newType; set->finalize(); } + + // If this set was not processed earlier - that is, if it is in + // unreachable code - then it may have an incompatible type. That is, + // If we saw a reachable set that writes type A, and this set writes + // type B, we may have specialized the local type to A, but the value + // of type B in this unreachable set is no longer valid to write to + // that local. In such a case we must do additional work. + if (!Type::isSubType(set->value->type, newType)) { + // The type is incompatible. To fix this, replace + // + // (set (bad-value)) + // + // with + // + // (set (block + // (drop (bad-value)) + // (unreachable) + // )) + // + // (We cannot just ignore the bad value, as it may contain a break to + // a target that is necessary for validation.) + Builder builder(*getModule()); + set->value = builder.makeSequence(builder.makeDrop(set->value), + builder.makeUnreachable()); + } } // Also update their parents. |