ELF and linking

The compiler produces a relocatable ELF64 .o file in pure Go, then shells out to the system ld for the final link.

Object writer

internal/object/elf/elf.go. Produces relocatable objects with the following sections, in order:

Section	Contents
.text	Code; one symbol per fn (and _start).
.rodata	Constant tensor data (only when present).
.note.GNU-stack	Empty; marks the stack non-executable.
.symtab	Symbol table.
.strtab	String table for symbol names.
.rela.text	Relocations against .text.

Relocation types emitted:

• R_X86_64_PLT32 — PC-relative call site.
• R_X86_64_PC32 — PC-relative load (used for rodata lea).

Symbols

Each user-defined function becomes a STT_FUNC symbol with the fn's name. Each rodata blob becomes STT_OBJECT. The driver also emits a separate _start global symbol pointing at the entry function so that ld -e _start resolves cleanly.

_start itself is emitted directly into .text by the backend; it calls main, then issues a Linux exit syscall (number 60) with main's return value as the exit status. There is no libc.

Linker driver

internal/link/link.go. A thin wrapper that builds the ld argument list, invokes it, and reports its exit code.

ld -o <out> -e _start <obj> [<runtime objects>]

There are no separate runtime objects to link in beyond what the driver appends to the user's .o directly (the print_* intrinsics — see x86 backend → Runtime intrinsics). There is no link-time optimisation step.

Inspection

./esquec build foo.esq --emit=obj -o foo.o
objdump -h foo.o            # section headers
objdump -t foo.o            # symbol table
objdump -d foo.o            # disassembly
objdump -r foo.o            # relocations
objdump -s -j .rodata foo.o # raw rodata bytes

The --keep-obj flag preserves the .o next to the executable.