My Little Object File: How Linkers Implement C++
summary
Walks a C++ translation unit through actual object formats and tools, showing how ELF, MachO, COFF encode sections, symbols and relocations and how the linker turns many .o files into an executable. Demonstrates with objdump/readelf outputs, shows init_array concatenation, comdat/weak selection for inline/template dedupe, ICF and relaxation merging identical code, garbage collection of unused sections, and PLT/GOT lazy binding for dynamic loads. Uses readelf objdump nm llvm-readobj and compares LD/Gold/LLD; the small examples run and produce the expected outputs.
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chapters (6)
- 0:00Introduction to build pipelines
- 1:13Inside an object file
- 2:42Linking mechanisms and data
- 23:31Linker operation and optimization
- 30:56Dynamic linking basics
- 33:35Q&A and best practices
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