[wasm] Check data segments for zero-sized memory.

According to the spec data segments are allowed even if the memory size
is zero. However, if one of the data segments has a length greater than
0, then module instantiation should fail.

I also changed the exception type in LoadDataSegments to TypeError,
because that's the exception type for all exceptions which can happen
during instantiation.

R=titzer@chromium.org, rossberg@chromium.org
TEST=cctest/test-run-wasm-module/EmptyMemoryEmptyDataSegment, cctest/test-run-wasm-module/EmptyMemoryNonEmptyDataSegment

Review-Url: https://codereview.chromium.org/2483053005
Cr-Commit-Position: refs/heads/master@{#40922}

src/wasm/wasm-module.cc

@@ -1078,6 +1078,8 @@ class WasmInstanceBuilder {
       RelocateMemoryReferencesInCode(code_table, old_mem_start, mem_start,
                                      old_mem_size, mem_size);
       compiled_module_->set_memory(memory_);
+    } else {
+      LoadDataSegments(nullptr, 0);
     }
 
     //--------------------------------------------------------------------------
@@ -1273,7 +1275,7 @@ class WasmInstanceBuilder {
     return result;
   }
 
-  uint32_t EvalUint32InitExpr(WasmInitExpr& expr) {
+  uint32_t EvalUint32InitExpr(const WasmInitExpr& expr) {
     switch (expr.kind) {
       case WasmInitExpr::kI32Const:
         return expr.val.i32_const;
@@ -1290,15 +1292,18 @@ class WasmInstanceBuilder {
   // Load data segments into the memory.
   void LoadDataSegments(Address mem_addr, size_t mem_size) {
     Handle<SeqOneByteString> module_bytes = compiled_module_->module_bytes();
-    for (auto segment : module_->data_segments) {
-      uint32_t dest_offset = EvalUint32InitExpr(segment.dest_addr);
+    for (const WasmDataSegment& segment : module_->data_segments) {
       uint32_t source_size = segment.source_size;
+      // Segments of size == 0 are just nops.
+      if (source_size == 0) continue;
+      uint32_t dest_offset = EvalUint32InitExpr(segment.dest_addr);
       if (dest_offset >= mem_size || source_size >= mem_size ||
           dest_offset > (mem_size - source_size)) {
-        thrower_->RangeError(
-            "data segment (start = %u, size = %u) does not fit into memory "
-            "(size = %zu)",
-            dest_offset, source_size, mem_size);
+        thrower_->TypeError("data segment (start = %" PRIu32 ", size = %" PRIu32
+                            ") does not fit into memory "
+                            "(size = %" PRIu64 ")",
+                            dest_offset, source_size,
+                            static_cast<uint64_t>(mem_size));
         return;
       }
       byte* dest = mem_addr + dest_offset;

test/cctest/wasm/test-run-wasm-module.cc

@@ -811,3 +811,106 @@ TEST(InitDataAtTheUpperLimit) {
   }
   Cleanup();
 }
+
+TEST(EmptyMemoryNonEmptyDataSegment) {
+  {
+    Isolate* isolate = CcTest::InitIsolateOnce();
+    HandleScope scope(isolate);
+    testing::SetupIsolateForWasmModule(isolate);
+
+    ErrorThrower thrower(isolate, "Run_WasmModule_InitDataAtTheUpperLimit");
+
+    const byte data[] = {
+        WASM_MODULE_HEADER,     // --
+        kMemorySectionCode,     // --
+        U32V_1(4),              // section size
+        ENTRY_COUNT(1),         // --
+        kResizableMaximumFlag,  // --
+        0,                      // initial size
+        0,                      // maximum size
+        kDataSectionCode,       // --
+        U32V_1(7),              // section size
+        ENTRY_COUNT(1),         // --
+        0,                      // linear memory index
+        WASM_I32V_1(8),         // destination offset
+        kExprEnd,
+        U32V_1(1),  // source size
+        'c'         // data bytes
+    };
+
+    testing::CompileInstantiateWasmModuleForTesting(isolate, &thrower, data,
+                                                    data + arraysize(data),
+                                                    ModuleOrigin::kWasmOrigin);
+    // It should not be possible to instantiate this module.
+    CHECK(thrower.error());
+  }
+  Cleanup();
+}
+
+TEST(EmptyMemoryEmptyDataSegment) {
+  {
+    Isolate* isolate = CcTest::InitIsolateOnce();
+    HandleScope scope(isolate);
+    testing::SetupIsolateForWasmModule(isolate);
+
+    ErrorThrower thrower(isolate, "Run_WasmModule_InitDataAtTheUpperLimit");
+
+    const byte data[] = {
+        WASM_MODULE_HEADER,     // --
+        kMemorySectionCode,     // --
+        U32V_1(4),              // section size
+        ENTRY_COUNT(1),         // --
+        kResizableMaximumFlag,  // --
+        0,                      // initial size
+        0,                      // maximum size
+        kDataSectionCode,       // --
+        U32V_1(6),              // section size
+        ENTRY_COUNT(1),         // --
+        0,                      // linear memory index
+        WASM_I32V_1(24),        // destination offset
+        kExprEnd,
+        U32V_1(0),  // source size
+    };
+
+    testing::CompileInstantiateWasmModuleForTesting(isolate, &thrower, data,
+                                                    data + arraysize(data),
+                                                    ModuleOrigin::kWasmOrigin);
+    // It should be possible to instantiate this module.
+    CHECK(!thrower.error());
+  }
+  Cleanup();
+}
+
+TEST(MemoryWithOOBEmptyDataSegment) {
+  {
+    Isolate* isolate = CcTest::InitIsolateOnce();
+    HandleScope scope(isolate);
+    testing::SetupIsolateForWasmModule(isolate);
+
+    ErrorThrower thrower(isolate, "Run_WasmModule_InitDataAtTheUpperLimit");
+
+    const byte data[] = {
+        WASM_MODULE_HEADER,      // --
+        kMemorySectionCode,      // --
+        U32V_1(4),               // section size
+        ENTRY_COUNT(1),          // --
+        kResizableMaximumFlag,   // --
+        1,                       // initial size
+        1,                       // maximum size
+        kDataSectionCode,        // --
+        U32V_1(9),               // section size
+        ENTRY_COUNT(1),          // --
+        0,                       // linear memory index
+        WASM_I32V_4(0x2468ace),  // destination offset
+        kExprEnd,
+        U32V_1(0),  // source size
+    };
+
+    testing::CompileInstantiateWasmModuleForTesting(isolate, &thrower, data,
+                                                    data + arraysize(data),
+                                                    ModuleOrigin::kWasmOrigin);
+    // It should be possible to instantiate this module.
+    CHECK(!thrower.error());
+  }
+  Cleanup();
+}