Avoid imported memories in the fuzzer (#5626)

We already did this for the first memory, and just needed to loop to handle initial
content in the test suite that has multiple memories.

Also clean up that code while I'm around, to avoid repeating
wasm.memories[0] all the time.

1 files changed, 15 insertions, 12 deletions

diff --git a/src/tools/fuzzing/fuzzing.cpp b/src/tools/fuzzing/fuzzing.cpp
index d904fd7bd..b69ff855e 100644
--- a/src/tools/fuzzing/fuzzing.cpp
+++ b/src/tools/fuzzing/fuzzing.cpp
@@ -196,6 +196,7 @@ void TranslateToFuzzReader::build() {
 void TranslateToFuzzReader::setupMemory() {
   // Add memory itself
   MemoryUtils::ensureExists(&wasm);
+  auto& memory = wasm.memories[0];
   if (wasm.features.hasBulkMemory()) {
     size_t memCovered = 0;
     // need at least one segment for memory.inits
@@ -213,14 +214,14 @@ void TranslateToFuzzReader::setupMemory() {
       if (!segment->isPassive) {
         segment->offset = builder.makeConst(int32_t(memCovered));
         memCovered += segSize;
-        segment->memory = wasm.memories[0]->name;
+        segment->memory = memory->name;
       }
       wasm.addDataSegment(std::move(segment));
     }
   } else {
     // init some data
     auto segment = builder.makeDataSegment();
-    segment->memory = wasm.memories[0]->name;
+    segment->memory = memory->name;
     segment->offset = builder.makeConst(int32_t(0));
     segment->setName(Name::fromInt(0), false);
     wasm.dataSegments.push_back(std::move(segment));
@@ -385,6 +386,7 @@ void TranslateToFuzzReader::setupTags() {
 }
 
 void TranslateToFuzzReader::finalizeMemory() {
+  auto& memory = wasm.memories[0];
   for (auto& segment : wasm.dataSegments) {
     Address maxOffset = segment->data.size();
     if (!segment->isPassive) {
@@ -409,26 +411,27 @@ void TranslateToFuzzReader::finalizeMemory() {
         maxOffset = maxOffset + offset->value.getInteger();
       }
     }
-    wasm.memories[0]->initial = std::max(
-      wasm.memories[0]->initial,
+    memory->initial = std::max(
+      memory->initial,
       Address((maxOffset + Memory::kPageSize - 1) / Memory::kPageSize));
   }
-  wasm.memories[0]->initial =
-    std::max(wasm.memories[0]->initial, USABLE_MEMORY);
+  memory->initial = std::max(memory->initial, USABLE_MEMORY);
   // Avoid an unlimited memory size, which would make fuzzing very difficult
   // as different VMs will run out of system memory in different ways.
-  if (wasm.memories[0]->max == Memory::kUnlimitedSize) {
-    wasm.memories[0]->max = wasm.memories[0]->initial;
+  if (memory->max == Memory::kUnlimitedSize) {
+    memory->max = memory->initial;
   }
-  if (wasm.memories[0]->max <= wasm.memories[0]->initial) {
+  if (memory->max <= memory->initial) {
     // To allow growth to work (which a testcase may assume), try to make the
     // maximum larger than the initial.
     // TODO: scan the wasm for grow instructions?
-    wasm.memories[0]->max = std::min(Address(wasm.memories[0]->initial + 1),
-                                     Address(Memory::kMaxSize32));
+    memory->max =
+      std::min(Address(memory->initial + 1), Address(Memory::kMaxSize32));
   }
   // Avoid an imported memory (which the fuzz harness would need to handle).
-  wasm.memories[0]->module = wasm.memories[0]->base = Name();
+  for (auto& memory : wasm.memories) {
+    memory->module = memory->base = Name();
+  }
 }
 
 void TranslateToFuzzReader::finalizeTable() {