Handles memory.grow failure in MultiMemoryLowering Pass (#5241)

Per the wasm spec, memory.grow instructions should return -1 when there is a failure to allocate enough memory. This PR adds support for returning this error code.

1 files changed, 9 insertions, 4 deletions

diff --git a/src/passes/MultiMemoryLowering.cpp b/src/passes/MultiMemoryLowering.cpp
index 9e9637b36..527a15804 100644
--- a/src/passes/MultiMemoryLowering.cpp
+++ b/src/passes/MultiMemoryLowering.cpp
@@ -304,12 +304,17 @@ struct MultiMemoryLowering : public Pass {
           sizeLocal, builder.makeMemorySize(combinedMemory, memoryInfo)));
     }
 
-    // TODO: Check the result of makeMemoryGrow for errors and return the error
-    // instead
+    // Attempt to grow the combinedMemory. If -1 returns, enough memory could
+    // not be allocated, so return -1.
     functionBody = builder.blockify(
       functionBody,
-      builder.makeDrop(builder.makeMemoryGrow(
-        builder.makeLocalGet(0, pointerType), combinedMemory, memoryInfo)));
+      builder.makeIf(
+        builder.makeBinary(
+          EqInt32,
+          builder.makeMemoryGrow(
+            builder.makeLocalGet(0, pointerType), combinedMemory, memoryInfo),
+          builder.makeConst(-1)),
+        builder.makeReturn(builder.makeConst(-1))));
 
     // If we are not growing the last memory, then we need to copy data,
     // shifting it over to accomodate the increase from page_delta