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Hi folks, When compiling the attached example with -ftrivial-auto-var-init=zero: $ clang -no-integrated-as -mno-sse -m64 -mstack-alignment=8 -O2 -ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang -g -o ipt.ll -c ipt.i -w -S -emit-llvm , Clang generates an initialization memset() call for |acpar| in the IR: %0 = bitcast %struct.xt_action_param* %acpar to i8*, !dbg !...

...ducate users that they're enabling a feature that might mutate from release to release, but hopefully the "experimental" string in the flag name indicates that, and as you say there's not much precedent for such noisy warnings. After all, you can have a really bad time by setting -mstack-alignment and not understanding the consequences. So I'm in favour of dropping the noisy warning idea. Thanks again for the input, and thanks James for your clarification. Best, Alex

...s, > > JF > > > On Aug 1, 2019, at 7:21 AM, Alexander Potapenko <glider at google.com> wrote: > > > > Hi folks, > > > > When compiling the attached example with -ftrivial-auto-var-init=zero: > > > > $ clang -no-integrated-as -mno-sse -m64 -mstack-alignment=8 -O2 > > -ftrivial-auto-var-init=zero > > -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang > > -g -o ipt.ll -c ipt.i -w -S -emit-llvm > > > > , Clang generates an initialization memset() call for |acpar| in the IR: > > >...

...- Changed code using xchgq. - patch v2: - Adapt patch to work post KPTI and compiler changes - Redo all performance testing with latest configs and compilers - Simplify mov macro on PIE (MOVABS now) - Reduce GOT footprint - 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 relocation space on mapped memory. It also simplifies the relocation process. - Move the start the module section next to the kernel. Remove the need for -mcmodel=large o...

...- Changed code using xchgq. - patch v2: - Adapt patch to work post KPTI and compiler changes - Redo all performance testing with latest configs and compilers - Simplify mov macro on PIE (MOVABS now) - Reduce GOT footprint - 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 relocation space on mapped memory. It also simplifies the relocation process. - Move the start the module section next to the kernel. Remove the need for -mcmodel=large o...

...t 7:21 AM, Alexander Potapenko <glider at google.com> wrote: > >>> > >>> Hi folks, > >>> > >>> When compiling the attached example with -ftrivial-auto-var-init=zero: > >>> > >>> $ clang -no-integrated-as -mno-sse -m64 -mstack-alignment=8 -O2 > >>> -ftrivial-auto-var-init=zero > >>> -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang > >>> -g -o ipt.ll -c ipt.i -w -S -emit-llvm > >>> > >>> , Clang generates an initialization memset() cal...

...te: >> > >>> >> > >>> Hi folks, >> > >>> >> > >>> When compiling the attached example with >> -ftrivial-auto-var-init=zero: >> > >>> >> > >>> $ clang -no-integrated-as -mno-sse -m64 -mstack-alignment=8 >> -O2 >> > >>> -ftrivial-auto-var-init=zero >> > >>> >> -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang >> > >>> -g -o ipt.ll -c ipt.i -w -S -emit-llvm >> > >>> >> > &...

...e ;) And if address of mStruct mod 4 = 0 and != mod 8, I got r2 the same as r1. Due I can't modify MachO binaries, I'm looking for a way to avoid orr and use add instruction here. Maybe it will not solve all of my problems due difference in ABI, I suggest it's the easiest way. I found -mstack-alignment= options, and I tried 4 value there for ELF build, but orr still used. BTW for x86_64 it worked, both on linux and mac. Another way, I think, it's make realignment inside all of ELF function, here could be a performance penalty, I tried -mstackrealign, but it wasn't lead to 8-byt...

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 relocation space on >> mapped memory. It also simplifies the relocation process. >> - Move the start the module section next to the kernel. R...

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 relocation space on >> mapped memory. It also simplifies the relocation process. >> - Move the start the module section next to the kernel. R...

...tch v2: > - Adapt patch to work post KPTI and compiler changes > - Redo all performance testing with latest configs and compilers > - Simplify mov macro on PIE (MOVABS now) > - Reduce GOT footprint > - 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 relocation space on > mapped memory. It also simplifies the relocation process. > - Move the start the module section next to the kernel. Remove the need for &...

Dear community, I faced with code which was generated by llvm, assembly instructions of that code is relying on 8-bytes alignment for structures on the stack. The part of Objective C code is following: -(void)getCharacters:(unichar *)unicode {     NSRange range;     range.location = 0;     range.length = [self length];     printf("%p, %p\n", &range.location, &range.length); And

...ble-pointer-types -Wno-initializer-overrides -Wno-unused-value -Wno-format -Wno-sign-compare -Wno-format-zero-length -Wno-uninitialized -std=gnu89 -fno-dwarf-directory-asm -fdebug-compilation-dir /home/dwmw2/git/linux-2.6 -ferror-limit 19 -fmessage-length 80 -pg -mfentry -fwrapv -stack-protector 2 -mstack-alignment=8 -fwchar-type=short -fno-signed-wchar -fobjc-runtime=gcc -fno-common -fdiagnostics-show-option -fcolor-diagnostics -vectorize-loops -vectorize-slp -o /tmp/core-26897d.s -x c arch/x86/events/core.c聽 1. <eof> parser at end of file 2. Per-module optimization passes 3. Running pass ...

Hi all, I encountered an error while compiling Linux kernel 5.3 to IR. My LLVM version is 9.0.0 release. This error said "invalid operand for inline asm constraint 'i'" in arch/x86/include/asm/jump_table.h. The source code is static __always_inline bool arch_static_branch(struct static_key *key, bool branch) { asm_volatile_goto("1:" ".byte "

...- Changed code using xchgq. - patch v2: - Adapt patch to work post KPTI and compiler changes - Redo all performance testing with latest configs and compilers - Simplify mov macro on PIE (MOVABS now) - Reduce GOT footprint - 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 relocation space on mapped memory. It also simplifies the relocation process. - Move the start the module section next to the kernel. Remove the need for -mcmodel=large o...

...2.6.17-1.2157_FC5xenU #1) ^MEIP is at network_tx_buf_gc+0xc4/0x1b7 [xennet] ^Meax: 00000011 ebx: 0000000c ecx: d9fc8cfc edx: 00000000 ^Mesi: 00000001 edi: d9fc8400 ebp: 0000000a esp: c0651d90 ^Mds: 007b es: 007b ss: 0069 ^MProcess swapper (pid: 0, threadinfo=c0650000 task=c05f1800) ^MStack: <0>d9fc8cfc 00000000 00000000 00000004 d9fc8000 0000f002 0000f003 0000effc ^M 00000000 d9fc8488 d9fc8400 d9fc8000 e10fe150 dba603e0 00000000 00000000 ^M 00000108 c043a57d 00000108 d9fc8000 c0651e3c c0651e3c 00000108 c0643800 ^MCall Trace: ^M <e10fe150> netif_int+0x24/0x6...

I've landed the patch in r324449. Before we merge this into two different Clang release branches and almost immediately release one of them, I would really like someone to confirm that this patch works well with the Linux kernel. David, if you're up for that, it would be great. Alternatively, Guenter or someone else here can help. On Tue, Feb 6, 2018 at 5:59 PM Chandler Carruth

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 relocation space on > mapped memory. It also simplifies the relocation process. > - Move the start the module section next to the kernel. Remove the need f...

...Thomas Garnier wrote: > 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 relocation space on >>> mapped memory. It also simplifies the relocation process. >>> - Move the start the module section n...

...- Changed code using xchgq. - patch v2: - Adapt patch to work post KPTI and compiler changes - Redo all performance testing with latest configs and compilers - Simplify mov macro on PIE (MOVABS now) - Reduce GOT footprint - 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 relocation space on mapped memory. It also simplifies the relocation process. - Move the start the module section next to the kernel. Remove the need for -mcmodel=large o...