5 files changed, 84 insertions, 0 deletions
diff --git a/src/binaryen-c.cpp b/src/binaryen-c.cpp
index 2260a93b1..7c826f0f2 100644
--- a/src/binaryen-c.cpp
+++ b/src/binaryen-c.cpp
@@ -3798,6 +3798,14 @@ void BinaryenSetLowMemoryUnused(bool on) {
   globalPassOptions.lowMemoryUnused = on != 0;
 }
 
+bool BinaryenGetZeroFilledMemory(void) {
+  return globalPassOptions.zeroFilledMemory;
+}
+
+void BinaryenSetZeroFilledMemory(bool on) {
+  globalPassOptions.zeroFilledMemory = on != 0;
+}
+
 bool BinaryenGetFastMath(void) { return globalPassOptions.fastMath; }
 
 void BinaryenSetFastMath(bool value) { globalPassOptions.fastMath = value; }
diff --git a/src/binaryen-c.h b/src/binaryen-c.h
index 8609496d0..08cf12b90 100644
--- a/src/binaryen-c.h
+++ b/src/binaryen-c.h
@@ -2284,6 +2284,13 @@ BINARYEN_API bool BinaryenGetLowMemoryUnused(void);
 // when optimizing. Applies to all modules, globally.
 BINARYEN_API void BinaryenSetLowMemoryUnused(bool on);
 
+// Gets whether to assume that an imported memory is zero-initialized.
+BINARYEN_API bool BinaryenGetZeroFilledMemory(void);
+
+// Enables or disables whether to assume that an imported memory is
+// zero-initialized.
+BINARYEN_API void BinaryenSetZeroFilledMemory(bool on);
+
 // Gets whether fast math optimizations are enabled, ignoring for example
 // corner cases of floating-point math like NaN changes.
 // Applies to all modules, globally.
diff --git a/src/js/binaryen.js-post.js b/src/js/binaryen.js-post.js
index d86cb07af..8e41b4e7c 100644
--- a/src/js/binaryen.js-post.js
+++ b/src/js/binaryen.js-post.js
@@ -3303,6 +3303,16 @@ Module['setLowMemoryUnused'] = function(on) {
   Module['_BinaryenSetLowMemoryUnused'](on);
 };
 
+// Gets whether that an imported memory will be zero-initialized speculation.
+Module['getZeroFilledMemory'] = function() {
+  return Boolean(Module['_BinaryenGetZeroFilledMemory']());
+};
+
+// Enables or disables whether that an imported memory will be
+// zero-initialized speculation.
+Module['setZeroFilledMemory'] = function(on) {
+  Module['_BinaryenSetZeroFilledMemory'](on);
+};
 // Gets whether fast math optimizations are enabled, ignoring for example
 // corner cases of floating-point math like NaN changes.
 Module['getFastMath'] = function() {
diff --git a/test/binaryen.js/zero-filled-memory.js b/test/binaryen.js/zero-filled-memory.js
new file mode 100644
index 000000000..0638c7744
--- /dev/null
+++ b/test/binaryen.js/zero-filled-memory.js
@@ -0,0 +1,31 @@
+var wast = String.raw`
+(module
+ (import "env" "memory" (memory $0 1))
+ (data (i32.const 1024) "\00\00\00\00")
+ (export "memory" (memory $0))
+)
+`;
+
+console.log("=== input wast ===" + wast);
+
+var module = binaryen.parseText(wast);
+
+console.log("=== unoptimized ===");
+assert(module.validate());
+console.log(module.emitText());
+
+console.log("=== optimized, zeroFilledMemory=" + binaryen.getZeroFilledMemory() + " ===");
+module.optimize();
+assert(module.validate());
+console.log(module.emitText());
+
+binaryen.setZeroFilledMemory(true);
+assert(binaryen.getZeroFilledMemory());
+console.log();
+
+console.log("=== optimized, zeroFilledMemory=" + binaryen.getZeroFilledMemory() + " ===");
+module.optimize();
+assert(module.validate());
+console.log(module.emitText());
+
+module.dispose();
diff --git a/test/binaryen.js/zero-filled-memory.js.txt b/test/binaryen.js/zero-filled-memory.js.txt
new file mode 100644
index 000000000..10f7a3fbe
--- /dev/null
+++ b/test/binaryen.js/zero-filled-memory.js.txt
@@ -0,0 +1,28 @@
+=== input wast ===
+(module
+ (import "env" "memory" (memory $0 1))
+ (data (i32.const 1024) "\00\00\00\00")
+ (export "memory" (memory $0))
+)
+
+=== unoptimized ===
+(module
+ (import "env" "memory" (memory $0 1))
+ (data (i32.const 1024) "\00\00\00\00")
+ (export "memory" (memory $0))
+)
+
+=== optimized, zeroFilledMemory=false ===
+(module
+ (import "env" "memory" (memory $0 1))
+ (data (i32.const 1024) "\00\00\00\00")
+ (export "memory" (memory $0))
+)
+
+
+=== optimized, zeroFilledMemory=true ===
+(module
+ (import "env" "memory" (memory $0 1))
+ (export "memory" (memory $0))
+)
+