Merge pull request #757 from WebAssembly/js-api

Tiny fixes for native wasm support

4 files changed, 32 insertions, 28 deletions

diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index b2e7f5512..9b503c84d 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -664,6 +664,10 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
     }, debug, false /* do not validate globally yet */);
   }
 
+  // if we see no function tables in the processing below, then the table still exists and has size 0
+
+  wasm.table.initial = wasm.table.max = 0;
+
   // first pass - do almost everything, but function imports and indirect calls
 
   for (unsigned i = 1; i < body->size(); i++) {
@@ -784,7 +788,6 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
           // TODO: when not using aliasing function pointers, we could merge them by noticing that
           //       index 0 in each table is the null func, and each other index should only have one
           //       non-null func. However, that breaks down when function pointer casts are emulated.
-          wasm.table.exists = true;
           if (wasm.table.segments.size() == 0) {
             wasm.table.segments.emplace_back(wasm.allocator.alloc<Const>()->set(Literal(uint32_t(0))));
           }
diff --git a/src/js/wasm.js-post.js b/src/js/wasm.js-post.js
index e7d461642..f093ff64d 100644
--- a/src/js/wasm.js-post.js
+++ b/src/js/wasm.js-post.js
@@ -223,13 +223,6 @@ function integrateWasmJS(Module) {
     env['memory'] = providedBuffer;
     assert(env['memory'] instanceof ArrayBuffer);
 
-    if (!('memoryBase' in env)) {
-      env['memoryBase'] = STATIC_BASE; // tell the memory segments where to place themselves
-    }
-    if (!('tableBase' in env)) {
-      env['tableBase'] = 0; // tell the memory segments where to place themselves
-    }
-
     wasmJS['providedTotalMemory'] = Module['buffer'].byteLength;
 
     // Prepare to generate wasm, using either asm2wasm or s-exprs
@@ -290,13 +283,21 @@ function integrateWasmJS(Module) {
 
     // import table
     if (!env['table']) {
-      var TABLE_SIZE = 1024; // TODO
+      var TABLE_SIZE = Module['wasmTableSize'];
+      if (TABLE_SIZE === undefined) TABLE_SIZE = 1024; // works in binaryen interpreter at least
       if (typeof WebAssembly === 'object' && typeof WebAssembly.Table === 'function') {
         env['table'] = new WebAssembly.Table({ initial: TABLE_SIZE, maximum: TABLE_SIZE, element: 'anyfunc' });
       } else {
         env['table'] = new Array(TABLE_SIZE); // works in binaryen interpreter at least
       }
     }
+
+    if (!env['memoryBase']) {
+      env['memoryBase'] = STATIC_BASE; // tell the memory segments where to place themselves
+    }
+    if (!env['tableBase']) {
+      env['tableBase'] = 0; // table starts at 0 by default, in dynamic linking this will change
+    }
     
     // try the methods. each should return the exports if it succeeded
 
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 33b5f5d16..075d013e5 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -615,7 +615,7 @@ struct PrintSExpression : public Visitor<PrintSExpression> {
   void printTableHeader(Table* curr) {
     printOpening(o, "table") << ' ';
     o << curr->initial;
-    if (curr->max && curr->max != Table::kMaxSize) o << ' ' << curr->max;
+    if (curr->max != Table::kMaxSize) o << ' ' << curr->max;
     o << " anyfunc)";
   }
   void visitTable(Table *curr) {
diff --git a/src/wasm-binary.h b/src/wasm-binary.h
index eef315fda..43a43b5c4 100644
--- a/src/wasm-binary.h
+++ b/src/wasm-binary.h
@@ -558,11 +558,11 @@ public:
     return ret;
   }
 
-  void writeResizableLimits(Address initial, Address maximum) {
-    uint32_t flags = maximum ? 1 : 0;
+  void writeResizableLimits(Address initial, Address maximum, bool hasMaximum) {
+    uint32_t flags = hasMaximum ? 1 : 0;
     o << U32LEB(flags);
     o << U32LEB(initial);
-    if (flags) {
+    if (hasMaximum) {
       o << U32LEB(maximum);
     }
   }
@@ -590,8 +590,7 @@ public:
     if (debug) std::cerr << "== writeMemory" << std::endl;
     auto start = startSection(BinaryConsts::Section::Memory);
     o << U32LEB(1); // Define 1 memory
-    Address max = wasm->memory.max == Memory::kMaxSize ? Address(0) : wasm->memory.max;
-    writeResizableLimits(wasm->memory.initial, max);
+    writeResizableLimits(wasm->memory.initial, wasm->memory.max, wasm->memory.max != Memory::kMaxSize);
     finishSection(start);
   }
 
@@ -639,13 +638,12 @@ public:
         case ExternalKind::Function: o << U32LEB(getFunctionTypeIndex(import->functionType->name)); break;
         case ExternalKind::Table: {
           o << U32LEB(BinaryConsts::ElementType::AnyFunc);
-          auto max = wasm->table.max == Table::kMaxSize ? Address(0) : wasm->table.max;
-          writeResizableLimits(wasm->table.initial, max);
+          writeResizableLimits(wasm->table.initial, wasm->table.max, wasm->table.max != Table::kMaxSize);
           break;
         }
         case ExternalKind::Memory: {
-          auto max = wasm->memory.max == Memory::kMaxSize ? Address(0) : wasm->memory.max;
-          writeResizableLimits(wasm->memory.initial, max); break;
+          writeResizableLimits(wasm->memory.initial, wasm->memory.max, wasm->memory.max != Memory::kMaxSize);
+          break;
         }
         case ExternalKind::Global:
           o << binaryWasmType(import->globalType);
@@ -850,8 +848,7 @@ public:
     auto start = startSection(BinaryConsts::Section::Table);
     o << U32LEB(1); // Declare 1 table.
     o << U32LEB(BinaryConsts::ElementType::AnyFunc);
-    Address max = wasm->table.max == Table::kMaxSize ? Address(0) : wasm->table.max;
-    writeResizableLimits(wasm->table.initial, max);
+    writeResizableLimits(wasm->table.initial, wasm->table.max, wasm->table.max != Table::kMaxSize);
     finishSection(start);
   }
 
@@ -1562,7 +1559,7 @@ public:
     auto numMemories = getU32LEB();
     if (!numMemories) return;
     assert(numMemories == 1);
-    getResizableLimits(wasm.memory.initial, &wasm.memory.max);
+    getResizableLimits(wasm.memory.initial, wasm.memory.max, Memory::kMaxSize);
   }
 
   void readSignatures() {
@@ -1606,12 +1603,12 @@ public:
     }
   }
 
-  void getResizableLimits(Address& initial, Address* max) {
+  void getResizableLimits(Address& initial, Address& max, Address defaultIfNoMax) {
     auto flags = getU32LEB();
     initial = getU32LEB();
     bool hasMax = flags & 0x1;
-    assert(max || !hasMax);
-    if (hasMax) *max = getU32LEB();
+    if (hasMax) max = getU32LEB();
+    else max = defaultIfNoMax;
   }
 
   void readImports() {
@@ -1640,10 +1637,13 @@ public:
           if (elementType != BinaryConsts::ElementType::AnyFunc) throw ParseException("Imported table type is not AnyFunc");
           wasm.table.exists = true;
           wasm.table.imported = true;
-          getResizableLimits(wasm.table.initial, &wasm.table.max);
+          getResizableLimits(wasm.table.initial, wasm.table.max, Table::kMaxSize);
+          break;
+        }
+        case ExternalKind::Memory: {
+          getResizableLimits(wasm.memory.initial, wasm.memory.max, Memory::kMaxSize);
           break;
         }
-        case ExternalKind::Memory: getResizableLimits(wasm.memory.initial, &wasm.memory.max); break;
         case ExternalKind::Global: {
           curr->globalType = getWasmType();
           auto globalMutable = getU32LEB();
@@ -1897,7 +1897,7 @@ public:
     wasm.table.exists = true;
     auto elemType = getU32LEB();
     if (elemType != BinaryConsts::ElementType::AnyFunc) throw ParseException("ElementType must be AnyFunc in MVP");
-    getResizableLimits(wasm.table.initial, &wasm.table.max);
+    getResizableLimits(wasm.table.initial, wasm.table.max, Table::kMaxSize);
   }
 
   void readTableElements() {