[AVR] llvm-objdump should automatically select the instruction set #146451
Description
Given a simple test program:
int adiw(int a) { return a + 51; }Build it with clang a.c --target=avr -mmcu=avr2 -c -O3, and then disassemble it with llvm-objdump -d a.o, we see
a.o: file format elf32-avr Disassembly of section .text: 00000000 <adiw>: 0: c3 96 08 95 <unknown>We must specify --mcpu=avr2 to llvm-objdump explicitly to make adiw correctly decoded.
a.o: file format elf32-avr Disassembly of section .text: 00000000 <adiw>: 0: c3 96 adiw r24, 0x33 2: 08 95 retHowever the generated object file does contain the avr2 family information.
ELF Header: Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00 Class: ELF32 Data: 2's complement, little endian Version: 1 (current) OS/ABI: UNIX - System V ABI Version: 0 Type: REL (Relocatable file) Machine: Atmel AVR 8-bit microcontroller Version: 0x1 Entry point address: 0x0 Start of program headers: 0 (bytes into file) Start of section headers: 284 (bytes into file) Flags: 0x82, EF_AVR_ARCH_AVR2, relaxable Size of this header: 52 (bytes) Size of program headers: 0 (bytes) Number of program headers: 0 Size of section headers: 40 (bytes) Number of section headers: 5 Section header string table index: 1So the llvm-objdump should automatically select the avr family according to ELF header, other than rely on user's explicit specification.