Summary:
GNU nm (and other nm implementations, such as "go tool nm") prints an explicit "no symbols" message when an object file has no symbols. Currently llvm-nm just doesn't print anything. Adding an explicit "no symbols" message will allow llvm-nm to be used in place of nm: some scripts and build processes use `nm <file> | grep "no symbols"` as a test to see if a file has no symbols. It will also be more familiar to anyone used to nm.
That said, the format implemented here is slightly different, in that it doesn't print the tool name in the message (which IMHO is not useful to include).
Demo:
```
$ for nm in nm bin/llvm-nm ; do echo "nm implementation: $nm"; $nm /tmp/foo{1,2}.o; echo; done
nm implementation: nm
/tmp/foo1.o:
nm: /tmp/foo1.o: no symbols
/tmp/foo2.o:
0000000000000000 T foo2
nm implementation: bin/llvm-nm
/tmp/foo1.o:
no symbols
/tmp/foo2.o:
0000000000000000 T foo2
```
Reviewers: MaskRay
Reviewed By: MaskRay
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52810
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@343742 91177308-0d34-0410-b5e6-96231b3b80d8
The implementation might be better to have a method is64Bit() in the class
SymbolicFile instead of having the static routine isSymbolList64Bit() in
llvm-nm.cpp . But this is very much in the sprit of isObject() and
getNMTypeChar() in llvm-nm.cpp that has a series of if else statements
based on the specific class of the SymbolicFile. I can update this if
folks would like.
Also the tests were updated to be explicit about checking the address for
64-bits or 32-bits from object files.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208463 91177308-0d34-0410-b5e6-96231b3b80d8
COFF has only one symbol table.
MachO has a LC_DYSYMTAB, but that is not a symbol table, just extra info about
the one symbol table (LC_SYMTAB).
IR (coming soon) also has only one table.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200488 91177308-0d34-0410-b5e6-96231b3b80d8
