search for: no_dead_strip

...i32 0 } !2 = metadata !{ i32 1, metadata !"Objective-C Garbage Collection", i32 2 } !3 = metadata !{ i32 3, metadata !"Objective-C Garbage Collection", metadata !{ metadata !"Objective-C Image Info Section", metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip" } } !4 = metadata !{ i32 1, metadata !"Objective-C Image Info Section", metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip" } !llvm.module.flags = !{ !0, !1, !2, !3, !4 } Module B -------- !0 = metadata !{ i32 1, metadata !"Objective-C Ver...

...adata !{ i32 1, metadata !"Objective-C Garbage Collection", i32 2 } > !3 = metadata !{ i32 3, metadata !"Objective-C Garbage Collection", >  metadata !{ >    metadata !"Objective-C Image Info Section", >    metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip" >  } > } > !4 = metadata !{ i32 1, metadata !"Objective-C Image Info Section", >                 metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip" } > !llvm.module.flags = !{ !0, !1, !2, !3, !4 } > > Module B > -------- > !0 = metadata...

...metadata !"Objective-C Garbage Collection", i32 2 } >> !3 = metadata !{ i32 3, metadata !"Objective-C Garbage Collection", >> metadata !{ >> metadata !"Objective-C Image Info Section", >> metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip" >> } >> } >> !4 = metadata !{ i32 1, metadata !"Objective-C Image Info Section", >> metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip" } >> !llvm.module.flags = !{ !0, !1, !2, !3, !4 } >> >> Module B &gt...

...!{ i32 1, metadata !"Objective-C Garbage Collection", i32 2 } > !3 = metadata !{ i32 3, metadata !"Objective-C Garbage Collection", > metadata !{ > metadata !"Objective-C Image Info Section", > metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip" > } > } > !4 = metadata !{ i32 1, metadata !"Objective-C Image Info Section", > metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip" } > !llvm.module.flags = !{ !0, !1, !2, !3, !4 } > > Module B > -------- > !0 = meta...

When I compile this LLVM IR…. @0 = private constant [19 x i8] c"V4main10Brightness\00", section "__TEXT,__swift3_typeref, regular, no_dead_strip" @1 = private constant [9 x i8] c"Vs5UInt8\00", section "__TEXT,__swift3_typeref, regular, no_dead_strip" @2 = private constant [18 x i8] c"currentBrightness\00", section "__TEXT,__swift3_reflstr, regular, no_dead_strip" @_TMRfV4main10Brightness = intern...

...ot;Objective-C Garbage Collection", i32 2 } >>> !3 = metadata !{ i32 3, metadata !"Objective-C Garbage Collection", >>> metadata !{ >>> metadata !"Objective-C Image Info Section", >>> metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip" >>> } >>> } >>> !4 = metadata !{ i32 1, metadata !"Objective-C Image Info Section", >>> metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip" } >>> !llvm.module.flags = !{ !0, !1, !2, !3, !4 } >>>...

...ng about the feasibility of collapsing the following two globals within llvm-link: @"OBJC_CLASSLIST_REFERENCES_$_2" = private global %struct.objc_class* bitcast (%struct._class_t* @"OBJC_CLASS_$_NSString" to %struct.objc_class*), section "__DATA, __objc_classrefs, regular, no_dead_strip", align 4 @"OBJC_CLASSLIST_REFERENCES_$_8" = private global %struct.objc_class* bitcast (%struct._class_t* @"OBJC_CLASS_$_NSString" to %struct.objc_class*), section "__DATA, __objc_classrefs, regular, no_dead_strip", align 4 The reason we'd like to do it in l...

...ibute(used)__ which 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? 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 Au...

> -----Original Message----- > From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Tim > Northover via llvm-dev > Sent: Wednesday, July 25, 2018 3:07 AM > To: Nat! > Cc: LLVM Developers Mailing List > Subject: Re: [llvm-dev] A question to the DWARF experts on symbol > indirection > > Hi Nat!, > > On Wed, 25 Jul 2018 at 01:21, Nat! via

...s for global variables that I haven't yet removed. E.g., I couldn't erase: @"\01L_OBJC_SELECTOR_REFERENCES_" = internal global i8* getelementptr inbounds ([20 x i8]* inttoptr (i64 4295929920 to [20 x i8]*), i32 0, i32 0), section "__DATA, __objc_selrefs, literal_pointers, no_dead_strip" because the initializer for @llvm.used = appending global [2 x i8*] [i8* getelementptr inbounds ([20 x i8]* inttoptr (i64 4295929920 to [20 x i8]*), i32 0, i32 0), i8* bitcast (i8** @"\01L_OBJC_SELECTOR_REFERENCES_" to i8*)] which I had previously erased, was still claimed as a...

...never > actually called visibly from anywhere, it’s probably not needed. However > there is the .no_daed_strip directive. Thus if we graft this slightly different: > > .section __TEXT,__text > .globl _main > > .long 1 > _main: > inc %eax > ret > > .no_dead_strip _main.dsp > .alt_entry _main.dsp > _main.dsp = _main-4 > > .subsections_via_symbols > > we still get a warning, but it won’t get stripped. At that point however, > we don’t need the .alt_entry > anymore (and can drop the warning). > > Thus, I’d propose that f...

...bably not needed. However > there is the .no_daed_strip > > directive. Thus if we graft this slightly different: > > > > .section __TEXT,__text > > .globl _main > > > > .long 1 > > _main: > > inc %eax > > ret > > > > .no_dead_strip _main.dsp > > .alt_entry _main.dsp > > _main.dsp = _main-4 > > > > .subsections_via_symbols > > > > we still get a warning, but it won’t get stripped. At that point > however, we don’t need the .alt_entry > > anymore (and can drop the warning)....

.../ .globl - MCSA_Hidden, /// .hidden (ELF) - MCSA_IndirectSymbol, /// .indirect_symbol (MachO) - MCSA_Internal, /// .internal (ELF) - MCSA_LazyReference, /// .lazy_reference (MachO) - MCSA_Local, /// .local (ELF) - MCSA_NoDeadStrip, /// .no_dead_strip (MachO) - MCSA_PrivateExtern, /// .private_extern (MachO) - MCSA_Protected, /// .protected (ELF) - MCSA_Reference, /// .reference (MachO) - MCSA_Weak, /// .weak - MCSA_WeakDefinition, /// .weak_definition (MachO) - MCSA_WeakReference /// .w...

...rip > > > directive. Thus if we graft this slightly different: > > > > > > .section __TEXT,__text > > > .globl _main > > > > > > .long 1 > > > _main: > > > inc %eax > > > ret > > > > > > .no_dead_strip _main.dsp > > > .alt_entry _main.dsp > > > _main.dsp = _main-4 > > > > > > .subsections_via_symbols > > > > > > we still get a warning, but it won’t get stripped. At that point > however, we don’t need the .alt_entry > > >...

...x i8], [8 x i8]* @OBJC_METH_VAR_NAME_, i32 0, i32 0), i8* getelementptr inbounds ([16 x i8], [16 x i8]* @OBJC_METH_VAR_TYPE_, i32 0, i32 0), i32 0, i8* bitcast (void (i8*, i32, %"struct.Foo::p.test1::"*)* @"+[Foo test1::]" to i8*) }] }, section "_DATA,__cls_meth,regular,no_dead_strip", align 4 @OBJC_CLASS_Foo = private global %struct._mulle_objc_loadclass { i32 -941529232, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @OBJC_CLASS_NAME_, i32 0, i32 0), i32 298441816, i32 0, i8* null, i32 0, i32 -1, i32 0, %struct._mulle_objc_ivarlist* null, %struct._mulle_objc_methodl...

...this example, LTO is concatenating the imageinfo sections instead of performing a proper merge. Here are the LLVM global variables that contain the imageinfo information. -fno-objc-gc: @OBJC_IMAGE_INFO = private constant [2 x i32] [i32 0, i32 16], section "__DATA, __objc_imageinfo, regular, no_dead_strip" -fobjc-gc-only: @OBJC_IMAGE_INFO = private constant [2 x i32] [i32 0, i32 22], section "__DATA, __objc_imageinfo, regular, no_dead_strip" With module-level attributes, these global variables wouldn't exist. Instead, they would be replaced by something like this: -fno-objc-gc:...

...? Code i used that does not work (but does if !dbg !14 is added): ; ModuleID = 'meh' @.str0 = linker_private constant [7 x i8] c"heh %b\00", align 1 @"\01L_OBJC_IMAGE_INFO" = internal constant [2 x i32] [i32 0, i32 16], section "__DATA, __objc_imageinfo, regular, no_dead_strip" @llvm.used = appending global [1 x i8*] [i8* bitcast ([2 x i32]* @"\01L_OBJC_IMAGE_INFO" to i8*)], section "llvm.metadata" define i32 @main() uwtable { %b = alloca i32 %Result = alloca i32 call void @llvm.dbg.declare(metadata !{i32* %b}, metadata !10) call vo...

That is in theory what omitting the .subsections_via_symbols directive is supposed to do, but in an experiment I ran a year or two ago I found that the Mach-O linker was still dead stripping on symbol boundaries with this directive omitted. In any case, a more precise approach has more recently (~a few months ago) become possible. There is a relatively new asm directive called .altentry that, as