From 50f5b3f226a4355beb4f0f3a28daa5987b04c2a4 Mon Sep 17 00:00:00 2001
From: Jon Meow <46229924+jonmeow@users.noreply.github.com>
Date: Wed, 16 Feb 2022 10:10:58 -0800
Subject: [PATCH] Stop using fuzz input for filenames (#1078)

---
 toolchain/lexer/tokenized_buffer_fuzzer.cpp | 24 +--------------------
 toolchain/parser/parse_tree_fuzzer.cpp      | 22 +------------------
 2 files changed, 2 insertions(+), 44 deletions(-)

diff --git a/toolchain/lexer/tokenized_buffer_fuzzer.cpp b/toolchain/lexer/tokenized_buffer_fuzzer.cpp
index bf3f35d65695..3d54c7731562 100644
--- a/toolchain/lexer/tokenized_buffer_fuzzer.cpp
+++ b/toolchain/lexer/tokenized_buffer_fuzzer.cpp
@@ -16,28 +16,8 @@ namespace Carbon::Testing {
 // NOLINTNEXTLINE: Match the documented fuzzer entry point declaration style.
 extern "C" int LLVMFuzzerTestOneInput(const unsigned char* data,
                                       std::size_t size) {
-  // We need two bytes of data to compute a file name length.
-  if (size < 2) {
-    return 0;
-  }
-  uint16_t raw_filename_length;
-  std::memcpy(&raw_filename_length, data, 2);
-  data += 2;
-  size -= 2;
-  size_t filename_length = raw_filename_length;
-
-  // We need enough data to populate this filename length.
-  if (size < filename_length) {
-    return 0;
-  }
-  llvm::StringRef filename(reinterpret_cast<const char*>(data),
-                           filename_length);
-  data += filename_length;
-  size -= filename_length;
-
-  // The rest of the data is the source text.
   auto source = SourceBuffer::CreateFromText(
-      llvm::StringRef(reinterpret_cast<const char*>(data), size), filename);
+      llvm::StringRef(reinterpret_cast<const char*>(data), size));
 
   auto buffer = TokenizedBuffer::Lex(source, NullDiagnosticConsumer());
   if (buffer.HasErrors()) {
@@ -50,11 +30,9 @@ extern "C" int LLVMFuzzerTestOneInput(const unsigned char* data,
   // token stream.
   for (TokenizedBuffer::Token token : buffer.Tokens()) {
     int line_number = buffer.GetLineNumber(token);
-    (void)line_number;
     CHECK(line_number > 0) << "Invalid line number!";
     CHECK(line_number < INT_MAX) << "Invalid line number!";
     int column_number = buffer.GetColumnNumber(token);
-    (void)column_number;
     CHECK(column_number > 0) << "Invalid line number!";
     CHECK(column_number < INT_MAX) << "Invalid line number!";
   }
diff --git a/toolchain/parser/parse_tree_fuzzer.cpp b/toolchain/parser/parse_tree_fuzzer.cpp
index a877abeb119b..744cca060da0 100644
--- a/toolchain/parser/parse_tree_fuzzer.cpp
+++ b/toolchain/parser/parse_tree_fuzzer.cpp
@@ -18,28 +18,8 @@ namespace Carbon::Testing {
 // NOLINTNEXTLINE: Match the documented fuzzer entry point declaration style.
 extern "C" int LLVMFuzzerTestOneInput(const unsigned char* data,
                                       std::size_t size) {
-  // We need two bytes of data to compute a file name length.
-  if (size < 2) {
-    return 0;
-  }
-  uint16_t raw_filename_length;
-  std::memcpy(&raw_filename_length, data, 2);
-  data += 2;
-  size -= 2;
-  std::size_t filename_length = raw_filename_length;
-
-  // We need enough data to populate this filename length.
-  if (size < filename_length) {
-    return 0;
-  }
-  llvm::StringRef filename(reinterpret_cast<const char*>(data),
-                           filename_length);
-  data += filename_length;
-  size -= filename_length;
-
-  // The rest of the data is the source text.
   auto source = SourceBuffer::CreateFromText(
-      llvm::StringRef(reinterpret_cast<const char*>(data), size), filename);
+      llvm::StringRef(reinterpret_cast<const char*>(data), size));
 
   // Lex the input.
   auto tokens = TokenizedBuffer::Lex(source, NullDiagnosticConsumer());