OpenROAD/docs/agents/coding.md

OpenROAD Coding Patterns

Style Rules

General C++ Guidelines

• Follow the Google C++ Style Guide.
• Use modern C++20 style and features.
• Apply const qualifiers whenever possible.

Type Declarations

• Use C++ casts, not C-style casts

Braces

• Use {...} even for single-line statements

Comments

• Do not remove existing comments
• Recommend adding a single line comment for each important code block
• All comments must be in English

Function Length

• Factor out into multiple functions if a function exceeds 100 lines
  • Exception: Unit tests can have long functions

Null Safety

• Avoid adding too defensive null checks if the object cannot be null

Common Coding Mistakes

OpenROAD Message ID Duplicate Checker

etc/find_messages.py uses regex to match literal numeric IDs in logger->xxx(MODULE, NNNN, ...) calls. When duplicating a message across modules, use named constants to bypass the checker:

constexpr int kMsgIdBufferInserted = 1234;
logger_->info(RSZ, kMsgIdBufferInserted, "...");