[cc] support C99 compound literals

[jgarzik]

No description provided.

[Copilot]

Pull request overview

This PR implements support for C99 compound literals (§6.5.2.5), which allow creating unnamed objects with initializer-list syntax directly in expressions. The implementation correctly handles both automatic storage duration (block scope) and static storage duration (file scope) as required by the C99 standard.

Key changes:

• Parser now recognizes (type){initializer-list} syntax and handles incomplete array types (int[]){...}
• New CompoundLiteral AST node added to represent these expressions
• Linearizer generates appropriate storage (local variables or static globals) based on scope

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
cc/tests/datatypes/struct_type.rs	Adds 7 comprehensive tests covering basic usage, designated initializers, arrays, function arguments, address-of, and file-scope compound literals
cc/parse/parser.rs	Implements compound literal parsing in primary expressions and adds support for incomplete array types int[] in type names
cc/parse/ast.rs	Adds CompoundLiteral enum variant to ExprKind with appropriate documentation
cc/ir/linearize.rs	Implements three contexts for compound literals: initializers (creates static globals), lvalue (returns address), and rvalue (creates local storage with proper value/pointer semantics)
cc/arch/x86_64/codegen.rs	Updates global emission to treat symbols starting with '.' as local (not globally visible)
cc/arch/aarch64/codegen.rs	Updates global emission to treat symbols starting with '.' as local (not globally visible)
cc/doc/BUGS.md	Removes the compound literal bug entry since the feature is now implemented

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.