diff options
| -rw-r--r-- | src/ir/effects.h | 13 | ||||
| -rw-r--r-- | test/lit/gc-read-write-effects.wast | 50 |
2 files changed, 63 insertions, 0 deletions
diff --git a/src/ir/effects.h b/src/ir/effects.h index d52fcfb15..268a7b4e0 100644 --- a/src/ir/effects.h +++ b/src/ir/effects.h @@ -71,6 +71,10 @@ public: std::set<Name> globalsWritten; bool readsMemory = false; bool writesMemory = false; + // TODO: Type-based alias analysis. For example, writes to Arrays never + // interfere with reads from Structs. + bool readsHeap = false; + bool writesHeap = false; // A trap, either from an unreachable instruction, or from an implicit trap // that we do not ignore (see below). // Note that we ignore trap differences, so it is ok to reorder traps with @@ -105,6 +109,7 @@ public: return globalsRead.size() + globalsWritten.size() > 0; } bool accessesMemory() const { return calls || readsMemory || writesMemory; } + bool accessesHeap() const { return calls || readsHeap || writesHeap; } // Check whether this may transfer control flow to somewhere outside of this // expression (aside from just flowing out normally). That includes a break // or a throw (if the throw is not known to be caught inside this expression; @@ -143,6 +148,8 @@ public: (other.transfersControlFlow() && hasSideEffects()) || ((writesMemory || calls) && other.accessesMemory()) || ((other.writesMemory || other.calls) && accessesMemory()) || + ((writesHeap || calls) && other.accessesHeap()) || + ((other.writesHeap || other.calls) && accessesHeap()) || (danglingPop || other.danglingPop)) { return true; } @@ -202,6 +209,8 @@ public: calls = calls || other.calls; readsMemory = readsMemory || other.readsMemory; writesMemory = writesMemory || other.writesMemory; + readsHeap = readsHeap || other.readsHeap; + writesHeap = writesHeap || other.writesHeap; trap = trap || other.trap; implicitTrap = implicitTrap || other.implicitTrap; isAtomic = isAtomic || other.isAtomic; @@ -571,12 +580,14 @@ private: void visitRttSub(RttSub* curr) {} void visitStructNew(StructNew* curr) {} void visitStructGet(StructGet* curr) { + parent.readsHeap = true; // traps when the arg is null if (curr->ref->type.isNullable()) { parent.implicitTrap = true; } } void visitStructSet(StructSet* curr) { + parent.writesHeap = true; // traps when the arg is null if (curr->ref->type.isNullable()) { parent.implicitTrap = true; @@ -584,10 +595,12 @@ private: } void visitArrayNew(ArrayNew* curr) {} void visitArrayGet(ArrayGet* curr) { + parent.readsHeap = true; // traps when the arg is null or the index out of bounds parent.implicitTrap = true; } void visitArraySet(ArraySet* curr) { + parent.writesHeap = true; // traps when the arg is null or the index out of bounds parent.implicitTrap = true; } diff --git a/test/lit/gc-read-write-effects.wast b/test/lit/gc-read-write-effects.wast new file mode 100644 index 000000000..f487a92f5 --- /dev/null +++ b/test/lit/gc-read-write-effects.wast @@ -0,0 +1,50 @@ +;; NOTE: Assertions have been generated by update_lit_checks.py and should not be edited. + +;; Check that writing a struct field is not reordered with reading the same +;; struct field. + +;; RUN: wasm-opt -all --simplify-locals %s -S -o - | filecheck %s + +(module + (type $A (struct + (field (mut i32)) + )) + + ;; Check that this: + ;; + ;; y = a.0 + ;; a.0 = 10 + ;; return y + ;; + ;; Is not turned into this: + ;; + ;; a.0 = 10 + ;; return a.0 + ;; + ;; CHECK: (func $test (param $x (ref null $A)) (result i32) + ;; CHECK-NEXT: (local $y i32) + ;; CHECK-NEXT: (local.set $y + ;; CHECK-NEXT: (struct.get $A 0 + ;; CHECK-NEXT: (local.get $x) + ;; CHECK-NEXT: ) + ;; CHECK-NEXT: ) + ;; CHECK-NEXT: (struct.set $A 0 + ;; CHECK-NEXT: (local.get $x) + ;; CHECK-NEXT: (i32.const 10) + ;; CHECK-NEXT: ) + ;; CHECK-NEXT: (local.get $y) + ;; CHECK-NEXT: ) + (func $test (export "test") (param $x (ref null $A)) (result i32) + (local $y i32) + (local.set $y + (struct.get $A 0 + (local.get $x) + ) + ) + (struct.set $A 0 + (local.get $x) + (i32.const 10) + ) + (local.get $y) + ) +) |