[wasm] Improve error message in the streaming decoder

Bug: chromium:1213097
Change-Id: If768725a5645b7d21f59845692ca5491e8674bfa
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2940896Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74964}

src/wasm/streaming-decoder.cc

@@ -462,7 +462,7 @@ class AsyncStreamingDecoder::DecodeFunctionLength : public DecodeVarInt32 {
   explicit DecodeFunctionLength(SectionBuffer* section_buffer,
                                 size_t buffer_offset,
                                 size_t num_remaining_functions)
-      : DecodeVarInt32(kV8MaxWasmFunctionSize, "body size"),
+      : DecodeVarInt32(kV8MaxWasmFunctionSize, "function body size"),
         section_buffer_(section_buffer),
         buffer_offset_(buffer_offset),
         // We are reading a new function, so one function less is remaining.
@@ -549,8 +549,8 @@ AsyncStreamingDecoder::DecodeVarInt32::Next(AsyncStreamingDecoder* streaming) {
 
   if (value_ > max_value_) {
     std::ostringstream oss;
-    oss << "function size > maximum function size: " << value_ << " < "
-        << max_value_;
+    oss << "The value " << value_ << " for " << field_name_
+        << " exceeds the maximum allowed value of " << max_value_;
     return streaming->Error(oss.str());
   }
 

test/mjsunit/wasm/streaming-error-position.js

@@ -62,7 +62,7 @@ function testErrorPosition(bytes, pos, message) {
   bytes.emit_u8(kTypeSectionCode);
   bytes.emit_u32v(0xffffff23);
   let pos = bytes.length - 1;
-  testErrorPositionAsyncOnly(bytes, pos, 'maximum function size');
+  testErrorPositionAsyncOnly(bytes, pos, 'section length');
 })();
 
 (function testFunctionsCountInvalidVarint() {
@@ -110,7 +110,7 @@ function testErrorPosition(bytes, pos, message) {
   bytes.emit_u32v(0xffffff23);
 
   let pos = bytes.length - 1;
-  testErrorPositionAsyncOnly(bytes, pos, 'maximum function size');
+  testErrorPositionAsyncOnly(bytes, pos, 'functions count');
 })();
 
 (function testFunctionsCountDoesNotMatch() {
@@ -163,7 +163,7 @@ function testErrorPosition(bytes, pos, message) {
   bytes.emit_bytes([0x80, 0x80, 0x80, 0x80, 0x80, 0x00]);
 
   let pos = bytes.length - 1 - 1;
-  testErrorPositionAsyncOnly(bytes, pos, 'expected body size');
+  testErrorPositionAsyncOnly(bytes, pos, 'function body size');
 })();
 
 (function testBodySizeTooBig() {
@@ -192,7 +192,7 @@ function testErrorPosition(bytes, pos, message) {
   bytes.emit_u32v(0xffffff23);
 
   let pos = bytes.length - 1;
-  testErrorPositionAsyncOnly(bytes, pos, 'maximum function size');
+  testErrorPositionAsyncOnly(bytes, pos, 'function body size');
 })();
 
 (function testBodySizeDoesNotFit() {