[wasm] Make reported "column number" 1-based

We report the byte offset as column number, but devtools assumes them
to be 1-based and subtracts one unconditionally before further
processing it. It's a bit unfortunate, but because of that we have to
just add 1 to the reported column number on the public StackTrace API.

R=ahaas@chromium.org, titzer@chromium.org
BUG=chromium:613110

Review-Url: https://codereview.chromium.org/2071563002
Cr-Commit-Position: refs/heads/master@{#37036}

src/isolate.cc

@@ -621,6 +621,8 @@ class CaptureStackTraceHelper {
       Code* code = frame->LookupCode();
       int offset = static_cast<int>(frame->pc() - code->instruction_start());
       int position = code->SourcePosition(offset);
+      // Make position 1-based.
+      if (position >= 0) ++position;
       JSObject::AddProperty(stack_frame, column_key_,
                             isolate_->factory()->NewNumberFromInt(position),
                             NONE);

src/runtime/runtime-internal.cc

@@ -141,8 +141,9 @@ RUNTIME_FUNCTION(Runtime_ThrowWasmError) {
                       LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
     if (it.IsFound()) {
       DCHECK(JSReceiver::GetDataProperty(&it)->IsSmi());
+      // Make column number 1-based here.
       Maybe<bool> data_set = JSReceiver::SetDataProperty(
-          &it, handle(Smi::FromInt(byte_offset), isolate));
+          &it, handle(Smi::FromInt(byte_offset + 1), isolate));
       DCHECK(data_set.IsJust() && data_set.FromJust() == true);
       USE(data_set);
     }

test/cctest/wasm/test-wasm-stack.cc

@@ -110,12 +110,12 @@ TEST(CollectDetailedWasmStack_ExplicitThrowFromJs) {
       Execution::TryCall(isolate, js_trampoline, global, 1, args, &maybe_exc);
   CHECK(returnObjMaybe.is_null());
 
-  // Line number is 1-based, with 0 == kNoLineNumberInfo.
+  // The column is 1-based, so add 1 to the actual byte offset.
   ExceptionInfo expected_exceptions[] = {
       {"a", 3, 8},                                            // -
       {"js", 4, 2},                                           // -
-      {"<WASM UNNAMED>", static_cast<int>(wasm_index), 2},    // -
-      {"<WASM UNNAMED>", static_cast<int>(wasm_index_2), 1},  // -
+      {"<WASM UNNAMED>", static_cast<int>(wasm_index), 3},    // -
+      {"<WASM UNNAMED>", static_cast<int>(wasm_index_2), 2},  // -
       {"callFn", 1, 24}                                       // -
   };
   CheckExceptionInfos(isolate, maybe_exc.ToHandleChecked(),
@@ -155,10 +155,10 @@ TEST(CollectDetailedWasmStack_WasmError) {
       Execution::TryCall(isolate, js_trampoline, global, 1, args, &maybe_exc);
   CHECK(maybe_return_obj.is_null());
 
-  // Line number is 1-based, with 0 == kNoLineNumberInfo.
+  // The column is 1-based, so add 1 to the actual byte offset.
   ExceptionInfo expected_exceptions[] = {
-      {"<WASM UNNAMED>", static_cast<int>(wasm_index), 1},    // -
-      {"<WASM UNNAMED>", static_cast<int>(wasm_index_2), 1},  // -
+      {"<WASM UNNAMED>", static_cast<int>(wasm_index), 2},    // -
+      {"<WASM UNNAMED>", static_cast<int>(wasm_index_2), 2},  // -
       {"callFn", 1, 24}                                       //-
   };
   CheckExceptionInfos(isolate, maybe_exc.ToHandleChecked(),

test/cctest/wasm/test-wasm-trap-position.cc

@@ -88,8 +88,9 @@ TEST(Unreachable) {
       Execution::TryCall(isolate, js_trampoline, global, 1, args, &maybe_exc);
   CHECK(returnObjMaybe.is_null());
 
+  // The column is 1-based, so add 1 to the actual byte offset.
   ExceptionInfo expected_exceptions[] = {
-      {"<WASM UNNAMED>", static_cast<int>(wasm_index), 1},  // --
+      {"<WASM UNNAMED>", static_cast<int>(wasm_index), 2},  // --
       {"callFn", 1, 24}                                     // --
   };
   CheckExceptionInfos(isolate, maybe_exc.ToHandleChecked(),
@@ -129,10 +130,10 @@ TEST(IllegalLoad) {
       Execution::TryCall(isolate, js_trampoline, global, 1, args, &maybe_exc);
   CHECK(returnObjMaybe.is_null());
 
-  // Line number is 1-based, with 0 == kNoLineNumberInfo.
+  // The column is 1-based, so add 1 to the actual byte offset.
   ExceptionInfo expected_exceptions[] = {
-      {"<WASM UNNAMED>", static_cast<int>(wasm_index), 6},    // --
-      {"<WASM UNNAMED>", static_cast<int>(wasm_index_2), 2},  // --
+      {"<WASM UNNAMED>", static_cast<int>(wasm_index), 7},    // --
+      {"<WASM UNNAMED>", static_cast<int>(wasm_index_2), 3},  // --
       {"callFn", 1, 24}                                       // --
   };
   CheckExceptionInfos(isolate, maybe_exc.ToHandleChecked(),