C++ ELF symbols

12 Jan 2025

[ c++ design development debug ]

Sections

text section - instructions and read-only data
data section - initialized writable data
bss section - uninitialized data

objdump -s values.o

Display the full contents of sections, often used in combination with -j to request specific sections.

objdump -j name values.o

Display information for section name.

objdump -d values.o

Display the assembler mnemonics for the machine instructions from the input file.

objdump -t values.o

Print the symbol table entries of the file. This is similar to the information provided by the nm program, although the display format is different.

nm values.o

lists the symbols from object files

readelf -SW values.o

Displays the information contained in the file’s section headers, if it has any.
Don’t break output lines to fit into 80 columns.

Relocations

objdump -dr -M intel values.o
Display the assembler mnemonics for the machine instructions from the input file.
Print the relocation entries of the file.
Pass target specific information to the disassembler.

Final binary

objdump -d -M intel the_program

If there were no symbols

gcc -o the_program values.o main.o
nm values.o
strip values.o
nm values.o
gcc -o the_program values.o main.o

Linkage

nm values.o

C++ headers

nm -C values.o
Decode (demangle) low-level symbol names into user-level names.

Weak symbols

nm values.o main.o

Linking weak symbols

objdump -h main.o | grep .text
Display summary information from the section headers of the object file.

Controlling visibility

target_compile_options(dynlib PRIVATE -fvisibility=hidden)
readelf -s values.o
Displays the entries in symbol table section of the file, if it has one.

References