| Message ID | 20190821185525.144151-1-pcc@google.com |
|---|---|
| State | New |
| Headers | show |
Am Mi., 21. Aug. 2019 um 21:27 Uhr schrieb Peter Collingbourne <pcc-at-google.com@ffmpeg.org>: > > As of LLVM r368102, Clang will set a pointer tag in bits 56-63 of the > address of a global when compiling with -fsanitize=hwaddress. This requires > an adjustment to assembly code that takes the address of such globals: the > code cannot use the regular R_AARCH64_ADR_PREL_PG_HI21 relocation to refer > to the global, since the tag would take the address out of range. Instead, > the code must use the non-checking (_NC) variant of the relocation (the > link-time check is substituted by a runtime check). > > This change makes the necessary adjustment in the movrel macro, where it is > needed when compiling with -fsanitize=hwaddress. Patch applied. Thank you, Carl Eugen
diff --git a/libavutil/aarch64/asm.S b/libavutil/aarch64/asm.S index 5c329430fd..3ac2ba0d52 100644 --- a/libavutil/aarch64/asm.S +++ b/libavutil/aarch64/asm.S @@ -32,6 +32,10 @@ # define FUNC # #endif +#ifndef __has_feature +# define __has_feature(x) 0 +#endif + .macro function name, export=0, align=2 .macro endfunc ELF .size \name, . - \name @@ -94,7 +98,11 @@ ELF .size \name, . - \name add \rd, \rd, :lo12:\val+(\offset) .endif #elif CONFIG_PIC +# if __has_feature(hwaddress_sanitizer) + adrp \rd, :pg_hi21_nc:\val+(\offset) +# else adrp \rd, \val+(\offset) +# endif add \rd, \rd, :lo12:\val+(\offset) #else ldr \rd, =\val+\offset
As of LLVM r368102, Clang will set a pointer tag in bits 56-63 of the address of a global when compiling with -fsanitize=hwaddress. This requires an adjustment to assembly code that takes the address of such globals: the code cannot use the regular R_AARCH64_ADR_PREL_PG_HI21 relocation to refer to the global, since the tag would take the address out of range. Instead, the code must use the non-checking (_NC) variant of the relocation (the link-time check is substituted by a runtime check). This change makes the necessary adjustment in the movrel macro, where it is needed when compiling with -fsanitize=hwaddress. Signed-off-by: Peter Collingbourne <pcc@google.com> --- libavutil/aarch64/asm.S | 8 ++++++++ 1 file changed, 8 insertions(+)