Module: libav
Branch: master
Commit: e5afa1b556542fd7a52a0a9b409c80f2e6e1e9bb
Author: Peter Collingbourne <p...@google.com>
Committer: Martin Storsjö <mar...@martin.st>
Date: Wed Aug 21 11:55:25 2019 -0700
aarch64: Add assembly support for -fsanitize=hwaddress tagged globals.
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 <p...@google.com>
Signed-off-by: Martin Storsjö <mar...@martin.st>
---
libavutil/aarch64/asm.S | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/libavutil/aarch64/asm.S b/libavutil/aarch64/asm.S
index bf5c1b7..81d723b 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
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