[builtins] Don't emit debug infos in release builds

Debug infos for embedded builtins (associating a file and line number
with certain code ranges) should only be emitted in debug modes.

This CL disables source position emission in Torque in release builds,
and adds checks that the external filename / source position lists are
empty in release builds.

Bug: v8:9910
Change-Id: Ic69683a2324c3b334150ee2b7da9972fbee56483
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1879903Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64576}

src/snapshot/embedded/embedded-file-writer.cc

@@ -40,6 +40,10 @@ void EmbeddedFileWriter::WriteBuiltin(PlatformEmbeddedFileWriterBase* w,
   v8::internal::SourcePositionTableIterator positions(
       vpos, SourcePositionTableIterator::kExternalOnly);
 
+#ifndef DEBUG
+  CHECK(positions.done());  // Release builds must not contain debug infos.
+#endif
+
   const uint8_t* data = reinterpret_cast<const uint8_t*>(
       blob->InstructionStartOfBuiltin(builtin_id));
   uint32_t size = blob->PaddedInstructionSizeOfBuiltin(builtin_id);

src/snapshot/embedded/embedded-file-writer.h

@@ -121,6 +121,11 @@ class EmbeddedFileWriter : public EmbeddedFileWriterInterface {
   }
 
   void WriteExternalFilenames(PlatformEmbeddedFileWriterBase* w) const {
+#ifndef DEBUG
+    // Release builds must not contain debug infos.
+    CHECK_EQ(external_filenames_by_index_.size(), 0);
+#endif
+
     w->Comment(
         "Source positions in the embedded blob refer to filenames by id.");
     w->Comment("Assembly directives here map the id to a filename.");

src/torque/csa-generator.cc

@@ -68,7 +68,10 @@ void CSAGenerator::EmitSourcePosition(SourcePosition pos, bool always_emit) {
 
 void CSAGenerator::EmitInstruction(const Instruction& instruction,
                                    Stack<std::string>* stack) {
+#ifdef DEBUG
   EmitSourcePosition(instruction->pos);
+#endif
+
   switch (instruction.kind()) {
 #define ENUM_ITEM(T)          \
   case InstructionKind::k##T: \