Design and Implement Stack Frame Layout

Layout Locals and Spills

The stack frame holds return address, saved frame pointer, callee-saved registers, spill slots, and local variables. Clang computes frame layout in TargetFrameLowering; debug info references stack offsets for each variable.

Frame Organization

Growing downward from high addresses: incoming arguments, return address, saved rbp, callee-saved regs, spill slots, local arrays, scalar locals. Each slot gets a negative offset from rbp or rsp.

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• Alignment: SSE needs 16-byte alignment
• Arrays may need dynamic alloca for large sizes
• Spill slots sized to register width (4 or 8 bytes)
• Frame pointer simplifies debug and unwinding

Connecting to real compilers

Production compilers embed this step inside a longer pipeline. GCC flows through cpp, cc1, assembly, and ld; Clang uses the driver, Sema, LLVM IR passes, and a target backend. LLVM bitcode, JVM bytecode, and WASM are other familiar IRs at the same layer. The exercise isolates one pass so you can test it alone before chaining it to the next stage.

Why for this exercise

You will design and implement stack frame layout for functions. This exercise requires assigning stack offsets to locals and spill slots and generating addressing modes that reference them.