[webkit-dev] LLInt alignment problem on ARM
Hello! I'm fighting with a strange LLInt alignment problem on ARM. As I see we put the LLInt code into .rodata section instead of .text. Is there a specific reason why we are doing this? If there is not I would put them to the .text section. Here is the objdump: ./Source/JavaScriptCore/.obj/release-shared/llint/LowLevelInterpreter.o: file format elf32-littlearm Disassembly of section .rodata: _ZStL19piecewise_construct: 0: andeq r0, r0, r0 0004 _ZStL13allocator_arg: 4: andeq r0, r0, r0 0008 _ZStL6ignore: ... 0009 llint_begin: 9: e30b3eefmovwr3, #48879 ; 0xbeef d: e34b3badmovtr3, #48045 ; 0xbbad 11: e583str r0, [r3] 15: e3a0mov r0, #0 19: e12fff30blx r0 001d llint_program_prologue: 1d: e1a0200emov r2, lr 21: e5852010str r2, [r5, #16] 25: e5951008ldr r1, [r5, #8] ... The problem is that these traditional instructions are lying on odd adresses in the .rodata section. Regards, Gabor ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev
Re: [webkit-dev] LLInt alignment problem on ARM
I believe that there’s a mnemonic that forces alignment that we could (arguably should?) be using before these labels. IIRC it’s something like .align N — if we aren’t doing this already we could make the lint assembler backend emit a .align 16 prior to each global symbol. —Oliver On Sep 26, 2013, at 1:09 AM, Gabor Rapcsanyi rga...@inf.u-szeged.hu wrote: Hello! I'm fighting with a strange LLInt alignment problem on ARM. As I see we put the LLInt code into .rodata section instead of .text. Is there a specific reason why we are doing this? If there is not I would put them to the .text section. Here is the objdump: ./Source/JavaScriptCore/.obj/release-shared/llint/LowLevelInterpreter.o: file format elf32-littlearm Disassembly of section .rodata: _ZStL19piecewise_construct: 0: andeq r0, r0, r0 0004 _ZStL13allocator_arg: 4: andeq r0, r0, r0 0008 _ZStL6ignore: ... 0009 llint_begin: 9: e30b3eefmovwr3, #48879 ; 0xbeef d: e34b3badmovtr3, #48045 ; 0xbbad 11: e583str r0, [r3] 15: e3a0mov r0, #0 19: e12fff30blx r0 001d llint_program_prologue: 1d: e1a0200emov r2, lr 21: e5852010str r2, [r5, #16] 25: e5951008ldr r1, [r5, #8] ... The problem is that these traditional instructions are lying on odd adresses in the .rodata section. Regards, Gabor ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev
Re: [webkit-dev] LLInt alignment problem on ARM
I’m wondering if the alignment is the traditional ARM vs Thumb 2. The movw after lint_begin with hex 0xe30b3eef is a Thumb 2 instruction. - Michael On Sep 26, 2013, at 9:24 AM, Oliver Hunt oli...@apple.com wrote: I believe that there’s a mnemonic that forces alignment that we could (arguably should?) be using before these labels. IIRC it’s something like .align N — if we aren’t doing this already we could make the lint assembler backend emit a .align 16 prior to each global symbol. —Oliver On Sep 26, 2013, at 1:09 AM, Gabor Rapcsanyi rga...@inf.u-szeged.hu wrote: Hello! I'm fighting with a strange LLInt alignment problem on ARM. As I see we put the LLInt code into .rodata section instead of .text. Is there a specific reason why we are doing this? If there is not I would put them to the .text section. Here is the objdump: ./Source/JavaScriptCore/.obj/release-shared/llint/LowLevelInterpreter.o: file format elf32-littlearm Disassembly of section .rodata: _ZStL19piecewise_construct: 0: andeq r0, r0, r0 0004 _ZStL13allocator_arg: 4: andeq r0, r0, r0 0008 _ZStL6ignore: ... 0009 llint_begin: 9: e30b3eefmovwr3, #48879 ; 0xbeef d: e34b3badmovtr3, #48045 ; 0xbbad 11: e583str r0, [r3] 15: e3a0mov r0, #0 19: e12fff30blx r0 001d llint_program_prologue: 1d: e1a0200emov r2, lr 21: e5852010str r2, [r5, #16] 25: e5951008ldr r1, [r5, #8] ... The problem is that these traditional instructions are lying on odd adresses in the .rodata section. Regards, Gabor ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev
