[RISC-V] Add support for AddressSanitizer on RISC-V GCC

[Joshua]

From: cooper.joshua <cooper.joshua@linux.alibaba.com>

    gcc/
    
        * config/riscv/riscv.c (asan_shadow_offset): Implement the offset of asan shadow memory for risc-v.
        (asan_shadow_offset): new macro definition.
---

 gcc/config/riscv/riscv.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c
index 63b0c38..b85b459 100644
--- a/gcc/config/riscv/riscv.c
+++ b/gcc/config/riscv/riscv.c
@@ -5292,6 +5292,14 @@ riscv_gpr_save_operation_p (rtx op)
   return true;
 }
 
+/* Implement TARGET_ASAN_SHADOW_OFFSET.  */
+
+static unsigned HOST_WIDE_INT
+riscv_asan_shadow_offset (void)
+{
+  return HOST_WIDE_INT_1U << 36;
+}
+
 /* Initialize the GCC target structure.  */
 #undef TARGET_ASM_ALIGNED_HI_OP
 #define TARGET_ASM_ALIGNED_HI_OP "\t.half\t"
@@ -5475,6 +5483,9 @@ riscv_gpr_save_operation_p (rtx op)
 #undef TARGET_NEW_ADDRESS_PROFITABLE_P
 #define TARGET_NEW_ADDRESS_PROFITABLE_P riscv_new_address_profitable_p
 
+#undef TARGET_ASAN_SHADOW_OFFSET
+#define TARGET_ASAN_SHADOW_OFFSET riscv_asan_shadow_offset
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 #include "gt-riscv.h"
-- 
2.7.4