search for: codemodel1

...olutely no assumptions about the addresses and data sections. But current LLVM LTO seems stick to use the small code model and generate many code with 32-bit RIP-relative addressing, which cause CPU exceptions when run in address larger than 2GB. > > Below, I just simply reuse the Eli's codemodel1.c example (link: http://eli.thegreenplace.net/2012/01/03/understanding-the-x64-code-models <http://eli.thegreenplace.net/2012/01/03/understanding-the-x64-code-models>) to show the LLVM LTO code model issue. > $ clang -g -O0 codemodel1.c -mcmodel=large -o codemodel1_large.bin > $ clang -...

...makes absolutely no assumptions about the addresses and data sections. But current LLVM LTO seems stick to use the small code model and generate many code with 32-bit RIP-relative addressing, which cause CPU exceptions when run in address larger than 2GB. Below, I just simply reuse the Eli's codemodel1.c example (link: http://eli.thegreenplace.net/2012/01/03/understanding-the-x64-code-models) to show the LLVM LTO code model issue. $ clang -g -O0 codemodel1.c -mcmodel=large -o codemodel1_large.bin $ clang -g -O0 codemodel1.c -mcmodel=small -o codemodel1_small.bin $ clang -g -O0 -flto codemodel1...

...inker which is different from the one in GNU Binutils? I'm a bit surprised if both OS X ld64 and gold plugin do not support large code model in LTO. Since modern system widely use the 64bit, the code need to run in high address (larger than 2 GB) is a reasonable requirement. $ gcc -g -O0 -flto codemodel1.c -mcmodel=large -o codemodel1_large_lto_gcc.bin $ objdump -dS codemodel1_large_lto_gcc.bin int main(int argc, const char* argv[]) { 40048b: 55 push %rbp 40048c: 48 89 e5 mov %rsp,%rbp 40048f: 48 83 ec 20 sub $0x20,%rs...

...quirement. The fact that we don't support it for now seems to indicate that it is not a widely requested feature, especially considering that it is really a trivial option to add. What is the linker you're using? Are you building your own clang? -- Mehdi > > $ gcc -g -O0 -flto codemodel1.c -mcmodel=large -o codemodel1_large_lto_gcc.bin > $ objdump -dS codemodel1_large_lto_gcc.bin > > int main(int argc, const char* argv[]) > { > 40048b: 55 push %rbp > 40048c: 48 89 e5 mov %rsp,%rbp > 40048f: 48 8...

> On May 17, 2016, at 11:21 AM, Umesh Kalappa <umesh.kalappa0 at gmail.com> wrote: > > Steven, > > As mehdi stated , the optimisation level is specific to linker and it > enables Inter-Pro opts passes ,please refer function To be very clear: the -O option may trigger *linker* optimizations as well, independently of LTO. -- Mehdi > >

...ort it for now seems to indicate that it is not a > widely requested feature, especially considering that it is really a trivial > option to add. > What is the linker you're using? Are you building your own clang? > > -- > Mehdi > > > > > > $ gcc -g -O0 -flto codemodel1.c -mcmodel=large -o > codemodel1_large_lto_gcc.bin > $ objdump -dS codemodel1_large_lto_gcc.bin > > int main(int argc, const char* argv[]) > { > 40048b: 55 push %rbp > 40048c: 48 89 e5 mov %rsp,%rbp > 40048f: 4...

...asonable requirement. The fact that we don't support it for now seems to indicate that it is not a widely requested feature, especially considering that it is really a trivial option to add. What is the linker you're using? Are you building your own clang? -- Mehdi $ gcc -g -O0 -flto codemodel1.c -mcmodel=large -o codemodel1_large_lto_gcc.bin $ objdump -dS codemodel1_large_lto_gcc.bin int main(int argc, const char* argv[]) { 40048b: 55 push %rbp 40048c: 48 89 e5 mov %rsp,%rbp 40048f: 48 83 ec 20 sub $0x20,%rs...

...rt it for now seems to indicate that it is not a widely requested feature, especially considering that it is really a trivial option to add. > What is the linker you're using? Are you building your own clang? > > -- > Mehdi > > > > > > $ gcc -g -O0 -flto codemodel1.c -mcmodel=large -o codemodel1_large_lto_gcc.bin > $ objdump -dS codemodel1_large_lto_gcc.bin > > int main(int argc, const char* argv[]) > { > 40048b: 55 push %rbp > 40048c: 48 89 e5 mov %rsp,%rbp > 40048f: 48 8...

...easonable requirement. The fact that we don't support it for now seems to indicate that it is not a widely requested feature, especially considering that it is really a trivial option to add. What is the linker you're using? Are you building your own clang? -- Mehdi $ gcc -g -O0 -flto codemodel1.c -mcmodel=large -o codemodel1_large_lto_gcc.bin $ objdump -dS codemodel1_large_lto_gcc.bin int main(int argc, const char* argv[]) { 40048b: 55 push %rbp 40048c: 48 89 e5 mov %rsp,%rbp 40048f: 48 83 ec 20 sub $0x20,%rs...

...widely requested feature, especially considering that it is really a trivial > > option to add. > > What is the linker you're using? Are you building your own clang? > > > > -- > > Mehdi > > > > > > > > > > > > $ gcc -g -O0 -flto codemodel1.c -mcmodel=large -o > > codemodel1_large_lto_gcc.bin > > $ objdump -dS codemodel1_large_lto_gcc.bin > > > > int main(int argc, const char* argv[]) > > { > > 40048b: 55 push %rbp > > 40048c: 48 89 e5 mov %rsp,%rbp > > 40048f: 48 83 ec 20 sub $0x20,%rsp...

...t it for now seems to indicate that it is not a widely requested feature, especially considering that it is really a trivial option to add. > What is the linker you're using? Are you building your own clang? > > -- > Mehdi > > > > > > $ gcc -g -O0 -flto codemodel1.c -mcmodel=large -o codemodel1_large_lto_gcc.bin > $ objdump -dS codemodel1_large_lto_gcc.bin > > int main(int argc, const char* argv[]) > { > 40048b: 55 push %rbp > 40048c: 48 89 e5 mov %rsp,%rbp > 40048f: 48 8...

...easonable requirement. The fact that we don't support it for now seems to indicate that it is not a widely requested feature, especially considering that it is really a trivial option to add. What is the linker you're using? Are you building your own clang? -- Mehdi $ gcc -g -O0 -flto codemodel1.c -mcmodel=large -o codemodel1_large_lto_gcc.bin $ objdump -dS codemodel1_large_lto_gcc.bin int main(int argc, const char* argv[]) { 40048b: 55 push %rbp 40048c: 48 89 e5 mov %rsp,%rbp 40048f: 48 83 ec 20 sub $0x20,%rs...