similar to: [llvm-mc] FreeBSD kernel module performance impact when upgrading clang

> You used -noinhibit-exec to ignore the diagnostic, which is usually a bad thing. I certainly agree with that. The point I was trying to make in my original email is that, specifically for kernel objects, this diagnostic is incorrect. R_X86_64_PC32 can be used safely against the symbol foo in that specific context, and should be possible without ignoring diagnostics. I wondered if there

On 7 June 2016 at 10:54, Shi, Steven <steven.shi at intel.com> wrote: > Hi Rafael, > I finally enable the clang LTO build with small code model and PIE, and my clang LTO Uefi firmware works now. Thank you! But I have one more issue on the clang normal build (without LTO) now. I find the small code model + "-fpie" build option will let clang generate some R_X86_64_GOTPCREL

OK, I get it. Adding "-pie" link option can force 64bits relocation address (e.g. EM_X86_64), instead of the 32bits one (e.g. R_X86_64_32S). I only used -fpic and -fpie in clang LTO compile option, and forgot add the "-pie" link option in ld. So my clang + ld LTO executable was still not position independent. Thank you all! Steven Shi Intel\SSG\STO\UEFI Firmware Tel: +86

On Wed, Mar 15, 2017 at 2:22 PM, Martin Richtarsky <s at martinien.de> wrote: > Here is the relevant output: > > 0000000000013832 <func()>: > 13832: 55 push %rbp > 13833: 48 89 e5 mov %rsp,%rbp > 13836: 53 push %rbx > 13837: 48 83 ec 18 sub $0x18,%rsp

On 31 May 2016 at 01:08, Shi, Steven <steven.shi at intel.com> wrote: > Hi Mehdi, > What's the default code model for x86_64 Mac OS X App? Andrew showed me some example code of Mac OS X App as below, which looks to use the small code model but can run at >4GB high address. Small, but PIC. > For example if you read a global like this the compiler will generate this code.

Hi Martin, It's hard to tell what is wrong only with the information. If that is an open-source program, can you give me a link to that so that I can try? If that's a proprietary software you cannot share with me, you might want to produce small reproducible test case. On Thu, Mar 23, 2017 at 1:10 AM, Martin Richtarsky <s at martinien.de> wrote: > Hi Rui, > > fyi I'm

> -----Original Message----- > From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of Fangrui > Song via llvm-dev > Sent: Thursday, August 20, 2020 10:18 PM > To: Leonard Chan <leonardchan at google.com> > Cc: llvm-dev <llvm-dev at lists.llvm.org> > Subject: [EXT] Re: [llvm-dev] [RFC][LLVM] New Constant type for > representing function PLT

Hi Lang, Yeah, I remember this case. Basically what’s happening is that there are relocations for ELF on x86 that use a value that is present in the object image as part of the calculation for the final value that goes in the same location. If you ever find yourself applying relocations for a second time (for instance, because the loaded object location is remapped for out-of-proc execution)

Hi, Mark > #pragma GCC visibility push(hidden) In theory - yes. > If so, what are the options I need to set when configuring llvm and > llvm-gcc? Well... No extra options are needed. > I'm able to compile the module with llvm-gcc (with the above pragma > included), but the kernel still rejects the module at load time saying the > module is compiled with PLT/GOT. Visibility

Gurus- Do llvm/llvm-gcc support pragma definitions for visibility like: #pragma GCC visibility push(hidden) If so, what are the options I need to set when configuring llvm and llvm-gcc? I'm able to compile the module with llvm-gcc (with the above pragma included), but the kernel still rejects the module at load time saying the module is compiled with PLT/GOT. Any Inputs, Insights? Thanks

Compilers don't know about functions that are not defined in the same compilation unit, so they leave call instruction operands as zero (because they can't compute any absolute nor relative address of the destinations), and let linkers fix the address by binary patching. So, what you are seeing is likely a bug of LLD that it fails to fix the address for some reason. Can you dump that

On Wed, Oct 11, 2017 at 2:34 PM, Tom Lendacky <thomas.lendacky at amd.com> wrote: > On 10/11/2017 3:30 PM, Thomas Garnier wrote: >> Changes: >> - patch v1: >> - Simplify ftrace implementation. >> - Use gcc mstack-protector-guard-reg=%gs with PIE when possible. >> - rfc v3: >> - Use --emit-relocs instead of -pie to reduce dynamic

On Wed, Oct 11, 2017 at 2:34 PM, Tom Lendacky <thomas.lendacky at amd.com> wrote: > On 10/11/2017 3:30 PM, Thomas Garnier wrote: >> Changes: >> - patch v1: >> - Simplify ftrace implementation. >> - Use gcc mstack-protector-guard-reg=%gs with PIE when possible. >> - rfc v3: >> - Use --emit-relocs instead of -pie to reduce dynamic

v1 was here: https://www.redhat.com/archives/libguestfs/2017-November/msg00068.html v1 -> v2: - Use a configure-time test. Rich.

Hi there, When I compile my code with -fdata-sections and -ffunction-sections, I still see some unused string in my shared library (Android). Actually, the strings appear together inside a .rodata.str1.1 section instead of getting their own section. It seems that the C-string literal are considered differently than other constant and the -fdata-sections is not respected in

I do have concerns about the amount of object level modeling that we want to do in the IR though. While it isn't the highest level IR we've managed to mostly avoid these kinds of features/complications in the past. I'm definitely interested in hearing some alternate implementations here and there rather than a full set of constants for relocations. Keeping the IR abstract enough over

I would think that the R_X86_64_PC32 relocation type should never be generated with large code model since large code model, by definition, makes no assumptions about the size or address of sections. The use of win32-elf might throw a wrinkle into this, since that is a code path that probably isn't exercised much outside of MCJIT use. That said, when this assertion fails it is usually

Not totally sure about this. Perhaps we should make ./configure look for the right asmrun library? Or make it user-configurable? Rich.

Compilation failure on c/s 17194 is as follows: /root/randy/vtd-stage/xen/common/built_in.o: In function `guest_remove_page'': /root/randy/vtd-stage/xen/common/memory.c:172: undefined reference to `__bitop_bad_size'' /root/randy/vtd-stage/xen/common/memory.c:172: relocation truncated to fit: R_X86_64_PC32 against undefined symbol `__bitop_bad_size''

Hi, I am profiling some workloads for the voluntary and involuntary context switches. I am interested in finding out the reasons causing these two types of context switches. As far as I understand, involuntary context switch happens on expiration of time slice or when a higher priority process comes in. While the voluntary switch generally happens when a process is waiting for I/O etc. So to