[RISCV][sanitizer] Fix sanitizer support for different virtual memory layout (#66743)

This PR combines the following reviews from Phabricator:
* https://reviews.llvm.org/D139823
* https://reviews.llvm.org/D139827

Other related (and merged) reviews are:
* https://reviews.llvm.org/D152895
* https://reviews.llvm.org/D152991
* https://reviews.llvm.org/D152990

---------

Co-authored-by: Kito Cheng <[email protected]>

Author: hau-hsu

compiler-rt/lib/asan/asan_mapping.h

@@ -72,7 +72,10 @@
 // || `[0x2000000000, 0x23ffffffff]` || LowShadow  ||
 // || `[0x0000000000, 0x1fffffffff]` || LowMem     ||
 //
-// Default Linux/RISCV64 Sv39 mapping:
+// Default Linux/RISCV64 Sv39 mapping with SHADOW_OFFSET == 0xd55550000;
+// (the exact location of SHADOW_OFFSET may vary depending the dynamic probing
+//  by FindDynamicShadowStart).
+//
 // || `[0x1555550000, 0x3fffffffff]` || HighMem    ||
 // || `[0x0fffffa000, 0x1555555fff]` || HighShadow ||
 // || `[0x0effffa000, 0x0fffff9fff]` || ShadowGap  ||
@@ -186,7 +189,7 @@
 #  elif SANITIZER_FREEBSD && defined(__aarch64__)
 #    define ASAN_SHADOW_OFFSET_CONST 0x0000800000000000
 #  elif SANITIZER_RISCV64
-#    define ASAN_SHADOW_OFFSET_CONST 0x0000000d55550000
+#    define ASAN_SHADOW_OFFSET_DYNAMIC
 #  elif defined(__aarch64__)
 #    define ASAN_SHADOW_OFFSET_CONST 0x0000001000000000
 #  elif defined(__powerpc64__)

compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp

@@ -1109,7 +1109,8 @@ uptr GetMaxVirtualAddress() {
 #  if SANITIZER_NETBSD && defined(__x86_64__)
   return 0x7f7ffffff000ULL;  // (0x00007f8000000000 - PAGE_SIZE)
 #  elif SANITIZER_WORDSIZE == 64
-#    if defined(__powerpc64__) || defined(__aarch64__) || defined(__loongarch__)
+#    if defined(__powerpc64__) || defined(__aarch64__) || \
+        defined(__loongarch__) || SANITIZER_RISCV64
   // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
   // We somehow need to figure out which one we are using now and choose
   // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
@@ -1118,9 +1119,8 @@ uptr GetMaxVirtualAddress() {
   // This should (does) work for both PowerPC64 Endian modes.
   // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
   // loongarch64 also has multiple address space layouts: default is 47-bit.
+  // RISC-V 64 also has multiple address space layouts: 39, 48 and 57-bit.
   return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
-#    elif SANITIZER_RISCV64
-  return (1ULL << 38) - 1;
 #    elif SANITIZER_MIPS64
   return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
 #    elif defined(__s390x__)

compiler-rt/lib/sanitizer_common/sanitizer_platform.h

@@ -295,8 +295,8 @@
 // For such platforms build this code with -DSANITIZER_CAN_USE_ALLOCATOR64=0 or
 // change the definition of SANITIZER_CAN_USE_ALLOCATOR64 here.
 #ifndef SANITIZER_CAN_USE_ALLOCATOR64
-#  if (SANITIZER_RISCV64 && !SANITIZER_FUCHSIA) || SANITIZER_IOS || \
-      SANITIZER_DRIVERKIT
+#  if (SANITIZER_RISCV64 && !SANITIZER_FUCHSIA && !SANITIZER_LINUX) || \
+      SANITIZER_IOS || SANITIZER_DRIVERKIT
 #    define SANITIZER_CAN_USE_ALLOCATOR64 0
 #  elif defined(__mips64) || defined(__hexagon__)
 #    define SANITIZER_CAN_USE_ALLOCATOR64 0
@@ -322,7 +322,7 @@
 #  if SANITIZER_FUCHSIA
 #    define SANITIZER_MMAP_RANGE_SIZE (1ULL << 38)
 #  else
-#    define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 47)
+#    define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 56)
 #  endif
 #elif defined(__aarch64__)
 #  if SANITIZER_APPLE

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -108,7 +108,7 @@ static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa0000;
 static const uint64_t kMIPS64_ShadowOffset64 = 1ULL << 37;
 static const uint64_t kAArch64_ShadowOffset64 = 1ULL << 36;
 static const uint64_t kLoongArch64_ShadowOffset64 = 1ULL << 46;
-static const uint64_t kRISCV64_ShadowOffset64 = 0xd55550000;
+static const uint64_t kRISCV64_ShadowOffset64 = kDynamicShadowSentinel;
 static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30;
 static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
 static const uint64_t kFreeBSDAArch64_ShadowOffset64 = 1ULL << 47;