Don't create a memory section for an imported memory; fixes #772 (#773)

9 files changed, 61 insertions, 20 deletions

diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index 9bf677e6f..836b8044a 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -998,6 +998,8 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
   memoryImport->module = ENV;
   memoryImport->base = MEMORY;
   memoryImport->kind = ExternalKind::Memory;
+  wasm.memory.exists = true;
+  wasm.memory.imported = true;
   wasm.addImport(memoryImport.release());
 
   // import table
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 075d013e5..c6fca0256 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -649,14 +649,7 @@ struct PrintSExpression : public Visitor<PrintSExpression> {
   }
   void visitMemory(Memory* curr) {
     // if memory wasn't imported, declare it
-    bool found = false;
-    for (auto& import : currModule->imports) {
-      if (import->kind == ExternalKind::Memory) {
-        found = true;
-        break;
-      }
-    }
-    if (!found) {
+    if (!curr->imported) {
       doIndent(o, indent);
       printMemoryHeader(curr);
       o << '\n';
diff --git a/src/wasm-binary.h b/src/wasm-binary.h
index 43a43b5c4..bdde2121e 100644
--- a/src/wasm-binary.h
+++ b/src/wasm-binary.h
@@ -586,7 +586,7 @@ public:
   }
 
   void writeMemory() {
-    if (wasm->memory.max == 0) return;
+    if (!wasm->memory.exists || wasm->memory.imported) return;
     if (debug) std::cerr << "== writeMemory" << std::endl;
     auto start = startSection(BinaryConsts::Section::Memory);
     o << U32LEB(1); // Define 1 memory
@@ -1559,6 +1559,8 @@ public:
     auto numMemories = getU32LEB();
     if (!numMemories) return;
     assert(numMemories == 1);
+    if (wasm.memory.exists) throw ParseException("Memory cannot be both imported and defined");
+    wasm.memory.exists = true;
     getResizableLimits(wasm.memory.initial, wasm.memory.max, Memory::kMaxSize);
   }
 
@@ -1641,6 +1643,8 @@ public:
           break;
         }
         case ExternalKind::Memory: {
+          wasm.memory.exists = true;
+          wasm.memory.imported = true;
           getResizableLimits(wasm.memory.initial, wasm.memory.max, Memory::kMaxSize);
           break;
         }
diff --git a/src/wasm-s-parser.h b/src/wasm-s-parser.h
index fda413f80..7946134cd 100644
--- a/src/wasm-s-parser.h
+++ b/src/wasm-s-parser.h
@@ -1447,11 +1447,10 @@ private:
     data.resize(actual);
   }
 
-  bool hasMemory = false;
-
   void parseMemory(Element& s, bool preParseImport = false) {
-    if (hasMemory) throw ParseException("too many memories");
-    hasMemory = true;
+    if (wasm.memory.exists) throw ParseException("too many memories");
+    wasm.memory.exists = true;
+    wasm.memory.imported = preParseImport;
     Index i = 1;
     if (s[i]->dollared()) {
       wasm.memory.name = s[i++]->str();
@@ -1470,6 +1469,12 @@ private:
       } else if (inner[0]->str() == IMPORT) {
         importModule = inner[1]->str();
         importBase = inner[2]->str();
+        auto im = make_unique<Import>();
+        im->kind = ExternalKind::Memory;
+        im->module = importModule;
+        im->base = importBase;
+        im->name = importModule;
+        wasm.addImport(im.release());
         i++;
       } else {
         assert(inner.size() > 0 ? inner[0]->str() != IMPORT : true);
@@ -1512,7 +1517,7 @@ private:
   }
 
   void parseData(Element& s) {
-    if (!hasMemory) throw ParseException("data but no memory");
+    if (!wasm.memory.exists) throw ParseException("data but no memory");
     Index i = 1;
     if (!s[i]->isList()) {
       // the memory is named
@@ -1545,7 +1550,7 @@ private:
       if (inner[0]->str() == FUNC) {
         ex->kind = ExternalKind::Function;
       } else if (inner[0]->str() == MEMORY) {
-        if (!hasMemory) throw ParseException("memory exported but no memory");
+        if (!wasm.memory.exists) throw ParseException("memory exported but no memory");
         ex->kind = ExternalKind::Memory;
       } else if (inner[0]->str() == TABLE) {
         ex->kind = ExternalKind::Table;
@@ -1558,7 +1563,7 @@ private:
     } else if (!s[2]->dollared() && !std::isdigit(s[2]->str()[0])) {
       ex->value = s[3]->str();
       if (s[2]->str() == MEMORY) {
-        if (!hasMemory) throw ParseException("memory exported but no memory");
+        if (!wasm.memory.exists) throw ParseException("memory exported but no memory");
         ex->kind = ExternalKind::Memory;
       } else if (s[2]->str() == TABLE) {
         ex->kind = ExternalKind::Table;
@@ -1585,8 +1590,9 @@ private:
         im->kind = ExternalKind::Function;
       } else if ((*s[3])[0]->str() == MEMORY) {
         im->kind = ExternalKind::Memory;
-        if (hasMemory) throw ParseException("too many memories");
-        hasMemory = true;
+        if (wasm.memory.exists) throw ParseException("more than one memory");
+        wasm.memory.exists = true;
+        wasm.memory.imported = true;
       } else if ((*s[3])[0]->str() == TABLE) {
         im->kind = ExternalKind::Table;
         if (wasm.table.exists) throw ParseException("more than one table");
@@ -1790,7 +1796,7 @@ private:
         im->kind = ExternalKind::Table;
         im->module = importModule;
         im->base = importBase;
-        im->name = importModule;// + "." + importBase;
+        im->name = importModule;
         wasm.addImport(im.release());
         i++;
       } else {
diff --git a/src/wasm-validator.h b/src/wasm-validator.h
index d01e61407..ad2b7e1a3 100644
--- a/src/wasm-validator.h
+++ b/src/wasm-validator.h
@@ -387,6 +387,9 @@ public:
     if (curr->kind == ExternalKind::Table) {
       shouldBeTrue(getModule()->table.imported, curr->name, "Table import record exists but table is not marked as imported");
     }
+    if (curr->kind == ExternalKind::Memory) {
+      shouldBeTrue(getModule()->memory.imported, curr->name, "Memory import record exists but memory is not marked as imported");
+    }
   }
 
   void visitExport(Export* curr) {
diff --git a/src/wasm.h b/src/wasm.h
index 0f542294c..44326948b 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -1502,7 +1502,11 @@ public:
   Address initial, max; // sizes are in pages
   std::vector<Segment> segments;
 
-  Memory() : initial(0), max(kMaxSize) {
+  // See comment in Table.
+  bool exists;
+  bool imported;
+
+  Memory() : initial(0), max(kMaxSize), exists(false), imported(false) {
     name = Name::fromInt(0);
   }
 };
diff --git a/test/memory-import.wast b/test/memory-import.wast
new file mode 100644
index 000000000..d7e6e3770
--- /dev/null
+++ b/test/memory-import.wast
@@ -0,0 +1,9 @@
+(module
+  (type $0 (func (result i32)))
+  (import "env" "memory" (memory $0 1 1))
+  (func $foo (type $0) (result i32)
+    (i32.load offset=13
+      (i32.const 37)
+    )
+  )
+)
diff --git a/test/memory-import.wast.fromBinary b/test/memory-import.wast.fromBinary
new file mode 100644
index 000000000..1ba3cb0f3
--- /dev/null
+++ b/test/memory-import.wast.fromBinary
@@ -0,0 +1,10 @@
+(module
+  (type $0 (func (result i32)))
+  (import "env" "memory" (memory $0 1 1))
+  (func $foo (type $0) (result i32)
+    (i32.load offset=13
+      (i32.const 37)
+    )
+  )
+)
+
diff --git a/test/memory-import.wast.fromBinary.noDebugInfo b/test/memory-import.wast.fromBinary.noDebugInfo
new file mode 100644
index 000000000..2ddf90ce9
--- /dev/null
+++ b/test/memory-import.wast.fromBinary.noDebugInfo
@@ -0,0 +1,10 @@
+(module
+  (type $0 (func (result i32)))
+  (import "env" "memory" (memory $0 1 1))
+  (func $0 (type $0) (result i32)
+    (i32.load offset=13
+      (i32.const 37)
+    )
+  )
+)
+