Tuesday, October 22, 2024 Richard Sandiford <richard.sandif...@arm.com> wrote:
>> If ASM_OUTPUT_ALIGNED_LOCAL uses an alignment less than BIGGEST_ALIGNMENT, >> it might trigger a relocation issue. >> >> relocation truncated to fit: IMAGE_REL_ARM64_PAGEOFFSET_12L > > Sorry to press the issue, but: why does that happen? #define IMAGE_REL_ARM64_PAGEOFFSET_12L 0x0007 /* The 12-bit page offset of the target, for instruction LDR (indexed, unsigned immediate). */ Based on the documentation for LDR https://developer.arm.com/documentation/ddi0596/2020-12/Base-Instructions/LDR--immediate---Load-Register--immediate-- "For the 64-bit variant: is the optional positive immediate byte offset, a multiple of 8 in the range 0 to 32760, defaulting to 0 and encoded in the "imm12" field as <pimm>/8" This means BIGGEST_ALIGNMENT (128) could be replaced with 64. auto rounded = ROUND_UP (MAX ((SIZE), 1), \ MAX ((ALIGNMENT), 64) / BITS_PER_UNIT); It works for most cases, however, not for all of them. cross-aarch64-w64-mingw32-msvcrt/lib/gcc/aarch64-w64-mingw32/15.0.0/libgomp.a(oacc-profiling.o): in function `goacc_profiling_initialize': mingw-woarm64-build/code/gcc/libgomp/oacc-profiling.c:105:(.text+0x2c): relocation truncated to fit: IMAGE_REL_ARM64_PAGEOFFSET_12L against `no symbol' This case should be investigated separately and fixed in the following patch series and BIGGEST_ALIGNMENT should be used for now. >>> Better to use "auto" rather than "unsigned". >> It looks like "auto" cannot be used there. > >What goes wrong if you use it? > >The reason for asking for "auto" was to avoid silent truncation. After the second try and recompiling, it looks like it works. Regards, Evgeny diff --git a/gcc/config/aarch64/aarch64-coff.h b/gcc/config/aarch64/aarch64-coff.h index 8fc6ca0440d..52c8c8d99c2 100644 --- a/gcc/config/aarch64/aarch64-coff.h +++ b/gcc/config/aarch64/aarch64-coff.h @@ -58,6 +58,13 @@ assemble_name ((FILE), (NAME)), \ fprintf ((FILE), "," HOST_WIDE_INT_PRINT_UNSIGNED "\n", (ROUNDED))) +#define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGNMENT) \ + { \ + auto rounded = ROUND_UP (MAX ((SIZE), 1), \ + MAX ((ALIGNMENT), BIGGEST_ALIGNMENT) / BITS_PER_UNIT); \ + ASM_OUTPUT_LOCAL (FILE, NAME, SIZE, rounded); \ + } + #define ASM_OUTPUT_SKIP(STREAM, NBYTES) \ fprintf (STREAM, "\t.space\t%d // skip\n", (int) (NBYTES))
