search for: subsections_via_symbol

...; > .long 1 > _main: > inc %eax > ret > > .globl _main.dsp > .alt_entry _main.dsp > What happens if you try ".alt_entry _main" instead? The alt_entry is supposed to be bound to the atom appearing *before* it. > _main.dsp = _main-4 > > .subsections_via_symbols > > (e.g. we inject the .alt_entry after the fact, pointing to the start of > the prefix data) > > this will yield: > > $ clang test.s -dead_strip > ld: warning: N_ALT_ENTRY bit set on first atom in section __TEXT/__text > And the prefix data will be stripped again. &g...

...itz.angermann at gmail.com > wrote: > Thank you Peter! > > That seems to do the trick! > > $ cat test.s > .section __TEXT,__text > .globl _main > > .long 1 > _main: > inc %eax > ret > > .alt_entry _main > _main.dsp = _main-4 > > .subsections_via_symbols > > > $ clang test.s -dead_strip > $ otool -vVtdj a.out > a.out: > _main.dsp: > 0000000100000fb1 01 00 addl %eax, (%rax) > 0000000100000fb3 00 00 addb %al, (%rax) > _main: > 0000000100000fb5 ff c0 incl %eax > 0000000100000fb7...

...; That seems to do the trick! > > > > $ cat test.s > > .section __TEXT,__text > > .globl _main > > > > .long 1 > > _main: > > inc %eax > > ret > > > > .alt_entry _main > > _main.dsp = _main-4 > > > > .subsections_via_symbols > > > > > > $ clang test.s -dead_strip > > $ otool -vVtdj a.out > > a.out: > > _main.dsp: > > 0000000100000fb1 01 00 addl %eax, (%rax) > > 0000000100000fb3 00 00 addb %al, (%rax) > > _main: > > 0000000100000fb5...

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...

Hi, I just came across a rather annoying behavior with llvm 3.9. Assuming the following samle code in test.ll: ; Lets have some global int x = 4 @x = global i32 10, align 4 ; and two strings "p = %d\n" for the prefix data, ; as well as "x = %d\n" to print the (global) x value. @.str = private unnamed_addr constant [8 x i8] c"x = %d\0A\00", align 1 @.str2 = private

...tions -fno-data-sections, it could mark nearly *everything* as .alt_entry -- except the first symbol in the object file) > > > On Mon, Mar 6, 2017 at 2:35 PM, Peter Collingbourne <peter at pcc.me.uk <mailto:peter at pcc.me.uk>> wrote: > 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 rela...

...ushq %rbp > Ltmp2: > .cfi_def_cfa_offset 16 > Ltmp3: > .cfi_offset %rbp, -16 > movq %rsp, %rbp > Ltmp4: > .cfi_def_cfa_register %rbp > movb %sil, %cl > rorl %cl, %edi<==== Rotate instruction > movl %edi, %eax > popq %rbp > ret > .cfi_endproc > .subsections_via_symbols > ====== > > I hope this helps. > > Michael > > On Jul 28, 2012, at 8:29 PM, reed kotler<rkotler at mips.com> wrote: > >> in C or C++, how can I get clang/llvm to try and do a "rotate". >> >> (want to test this code in the mips16 port) &gt...

...0xab,0xaa,0x00,0x00] ## imm = 0xAAAB shrl $17, %eax ## encoding: [0xc1,0xe8,0x11] ret ## encoding: [0xc3] .comm _last_tf_arg_u,8,3 ## @last_tf_arg_u ## @last_tf_arg_u .subsections_via_symbols Relatively recently, we turned on verbose-asm output by default in clang for -S output on targets that support the integrated assembler (which is almost all of them on x86 now). Does anyone have a reason to disable the encoding information? On the one hand it is fairly noisy, on the other han...

...ept patch to AsmWriter makes it work (although in a hackish way that I am NOT suggesting be committed as-is). With this patch, the you can compile this: %0 = type { i32, i32 } @structure = global %0 { i32 0, i32 1 } @element1 = alias getelementptr( %0* @structure, i32 0, i32 1) To this: .subsections_via_symbols .section __DATA,__data .align 3 _structure: ## @structure .space 4 .long 1 ## 0x1 .globl _element1 .set _element1, _structure+4 .size _element1, 4 .type...

...## @rotr .cfi_startproc ## BB#0: pushq %rbp Ltmp2: .cfi_def_cfa_offset 16 Ltmp3: .cfi_offset %rbp, -16 movq %rsp, %rbp Ltmp4: .cfi_def_cfa_register %rbp movb %sil, %cl rorl %cl, %edi <==== Rotate instruction movl %edi, %eax popq %rbp ret .cfi_endproc .subsections_via_symbols ====== I hope this helps. Michael On Jul 28, 2012, at 8:29 PM, reed kotler <rkotler at mips.com> wrote: > in C or C++, how can I get clang/llvm to try and do a "rotate". > > (want to test this code in the mips16 port) > > i.e. emit rotr node. > > tia. &g...

...e_instructions .globl _main .align 4, 0x90 _main: ## @main .cfi_startproc ## BB#0: ## %entry vmovups (%rdi), %xmm0 vinsertf128 $1, 16(%rdi), %ymm0, %ymm0 ret .cfi_endproc .subsections_via_symbols -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130709/f0222f43/attachment.html>

...me undefined behaviour that I’m not aware of. Other architectures appear to work OK. $ clang -arch arm64 -O1 test.c -S -o - .section __TEXT,__text,regular,pure_instructions .ios_version_min 5, 0 .globl _getVec3 .align 2 _getVec3: ; @getVec3 ; BB#0: b _getVec2 .subsections_via_symbols - - - - I’m happy to file a bug for this, but not sure quite where it belongs - clang, LLVM or direct to Apple. Can someone test the top of tree and see if it suffers the same issue? I’m currently using the latest Xcode from Apple (clang -v gives “Apple LLVM version 6.1.0 (clang-602.0.49) (base...

in C or C++, how can I get clang/llvm to try and do a "rotate". (want to test this code in the mips16 port) i.e. emit rotr node. tia. reed

On Mon, Mar 2, 2009 at 2:45 PM, Jonathan Turner <probata at hotmail.com> wrote: > For which version of gcc?  I should mention I'm on OS X and using the LLVM > SVN. gcc 4.3. It's also possible this is processor-sensitive. >> First, try looking at the generated code... the code LLVM generates is >> probably not what you're expecting. I'm getting the

...lt;def> ECX<kill> shrl %cl, %edi movl -4(%rbp), %eax movabsq $32, %rsi subq -16(%rbp), %rsi movl %esi, %edx movl %edx, %ecx ## kill: CL<def> ECX<kill> shll %cl, %eax orl %eax, %edi movl %edi, %eax popq %rbp ret .cfi_endproc .subsections_via_symbols ===== Michael On Jul 28, 2012, at 9:04 PM, reed kotler <rkotler at mips.com> wrote: > Nice! > > Clever compiler.. > > > On 07/28/2012 08:55 PM, Michael Gottesman wrote: >> I can get clang/llvm to emit a rotate instruction on x86-64 when compiling C by just using...

...414:Unknown pseudo-op: .p2align /var/tmp//ccOTBSDa.s:6414:Rest of line ignored. 1st junk character valued 50 (2). /var/tmp//ccOTBSDa.s:6608:Unknown pseudo-op: .p2align /var/tmp//ccOTBSDa.s:6608:Rest of line ignored. 1st junk character valued 50 (2). /var/tmp//ccOTBSDa.s:7111:Unknown pseudo-op: .subsections_via_symbols make: *** [corStruct.o] Error 1 ERROR: compilation failed for package 'nlme' _____________________________ Professor Michael Kubovy University of Virginia Department of Psychology USPS: P.O.Box 400400 Charlottesville, VA 22904-4400 Parcels: Room 102 Gilmer Hall...

...reinforce the "there be > dragons here" nature of this feature. It interacts with other parts of the > assembler and the underlying assumptions of the platform in interesting > ways. Lots of *really* careful test cases will be necessary. Yes I see your point. Thanks for brining .subsections_via_symbols to my attention.

...a > hackish way that I am NOT suggesting be committed as-is). > > With this patch, the you can compile this: > > %0 = type { i32, i32 } > @structure = global %0 { i32 0, i32 1 } > @element1 = alias getelementptr( %0* @structure, i32 0, i32 1) > > To this: > > .subsections_via_symbols > .section __DATA,__data > .align 3 > _structure: ## > @structure > .space 4 > .long 1 ## 0x1 > > .globl _element1 > .set _element1, _structure+4 >...

...wing name is not '#' combined.s:1370: Error: unknown pseudo-op: `.indirect_symbol' combined.s:1375: Error: unknown pseudo-op: `.lazy_symbol_pointer' combined.s:1377: Error: unknown pseudo-op: `.indirect_symbol' .. repeated a few times combined.s:1393: Error: unknown pseudo-op: `.subsections_via_symbols' Thank you, -aa -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20080319/4ca23d47/attachment.html>

..._2: ## bb1 movl %eax, 4(%esp) movl $LC, (%esp) call _printf xorl %eax, %eax addl $12, %esp ret .section __TEXT,__cstring,cstring_literals LC: ## LC .asciz "Timeout: %i\n" .subsections_via_symbols Setting the loops to decl instead of cmove/incl might seem like more work, but appears to be faster: .text .align 4,0x90 .globl _main _main: subl $12, %esp movl $2000, %eax movl $1000000000, %ecx .align 4,0x90 LBB1_3:...