search for: n_desc

...be set for each symbol, but this is only a compiler hint. The information is not passed in the symbol table. If this is not passed in the symbol table to the linker, why is it in the DefinedAtom ? > In mach-o it *is* passed on to the linker by the compiler. It is the N_NO_DEAD_STRIP bit in the n_desc field of the nlist struct. Are you saying that that information is not recorded in ELF .o files? On ELF x86_64, I dont see the information being passed. Is clang planning to add this support ? Thanks Shankar Easwaran -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted...

...could be set for each symbol, but this is only a compiler hint. The information is not passed in the symbol table. If this is not passed in the symbol table to the linker, why is it in the DefinedAtom ? In mach-o it *is* passed on to the linker by the compiler. It is the N_NO_DEAD_STRIP bit in the n_desc field of the nlist struct. Are you saying that that information is not recorded in ELF .o files? -Nick

Hi Nick, Dead stripping optimization needs a way to setup the roots which are live. The current code in Resolver does it by 1) setting all the global defined atoms to be the live set when building shared libraries (_options.allGlobalsAreDeadStripRoots) 2) Or, uses a list of names that are dead strip roots (other types) Question:- *********** How are the dead strip root names supposed to be

...ion because of #1 – it seems > like there should be a way to work around that. Perhaps there's something > we can change in ld64. > As far as I can tell, the "auto hide" property is independent of whether the symbol is actually hidden (the former is N_WEAK_DEF|N_WEAK_REF in n_desc, and the latter is N_PEXT in n_type). So perhaps what you can do is change ld64 to recognize N_WEAK_DEF|N_WEAK_REF together with N_PEXT as meaning "hidden and mergeable". Peter > > > Steven > > > >> On Feb 9, 2018, at 2:00 PM, Steven Wu via llvm-dev < > llv...

> On Feb 14, 2018, at 09:55, Steven Wu via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > I did a bit more digging for the auto hide problem. Here is my finding that prevent us from doing this by default in GlobalOpts > > 1. When a symbol is linkonce_odr hidden unnamed_addr, it emits both '.private_extern' and '.weak_def_can_be_hidden' asm directives on

...ve"); - Lex(); - - SMLoc DescLoc = Lexer.getLoc(); - int64_t DescValue; - if (ParseAbsoluteExpression(DescValue)) - return true; - - if (Lexer.isNot(AsmToken::EndOfStatement)) - return TokError("unexpected token in '.desc' directive"); - - Lex(); - - // Set the n_desc field of this Symbol to this DescValue - Out.EmitSymbolDesc(Sym, DescValue); - - return false; -} - -/// ParseDirectiveComm -/// ::= ( .comm | .lcomm ) identifier , size_expression [ , align_expression ] -bool AsmParser::ParseDirectiveComm(bool IsLocal) { - SMLoc IDLoc = Lexer.getLoc(); - Stri...