diff options
| -rw-r--r-- | src/ir/ExpressionManipulator.cpp | 3 | ||||
| -rw-r--r-- | src/ir/manipulation.h | 11 |
2 files changed, 13 insertions, 1 deletions
diff --git a/src/ir/ExpressionManipulator.cpp b/src/ir/ExpressionManipulator.cpp index 4cac87a01..51ed7552d 100644 --- a/src/ir/ExpressionManipulator.cpp +++ b/src/ir/ExpressionManipulator.cpp @@ -62,9 +62,10 @@ flexibleCopy(Expression* original, Module& wasm, CustomCopier custom) { #define DELEGATE_FIELD_CHILD(id, field) \ tasks.push_back({castOriginal->field, &castCopy->field}); +// Iterate in reverse order here so we visit children in normal order. #define DELEGATE_FIELD_CHILD_VECTOR(id, field) \ castCopy->field.resize(castOriginal->field.size()); \ - for (Index i = 0; i < castOriginal->field.size(); i++) { \ + for (auto i = int64_t(castOriginal->field.size()) - 1; i >= 0; i--) { \ tasks.push_back({castOriginal->field[i], &castCopy->field[i]}); \ } diff --git a/src/ir/manipulation.h b/src/ir/manipulation.h index 64cd15dc3..e7816af9f 100644 --- a/src/ir/manipulation.h +++ b/src/ir/manipulation.h @@ -68,6 +68,17 @@ inline OutputType* convert(InputType* input, MixedArena& allocator) { // expression before copying it. If it returns a non-null value then that is // used (effectively overriding the normal copy), and if it is null then we do a // normal copy. +// +// The order of iteration here is *pre*-order, that is, parents before children, +// so that it is possible to override an expression and all its children. +// Children themselves are visited in normal order. For example, this is the +// order of the following expression: +// +// (i32.add ;; visited first (and children not visited, if overridden) +// (call $a) ;; visited second +// (call $b) ;; visited third +// ) +// using CustomCopier = std::function<Expression*(Expression*)>; Expression* flexibleCopy(Expression* original, Module& wasm, CustomCopier custom); |