From 97ec1451a8f0ef9d845f3ca90bc7ba63d52bc0c5 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka@google.com>
Date: Wed, 13 Sep 2017 00:24:44 +0000
Subject: [PATCH] [compiler-rt] Move IsStackOverflow into
 sanitizer_posix_libcdep.cc to the rest of instrumentation code.

llvm-svn: 313100
---
 .../lib/sanitizer_common/sanitizer_posix.cc   | 47 -------------------
 .../sanitizer_posix_libcdep.cc                | 45 ++++++++++++++++++
 2 files changed, 45 insertions(+), 47 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc b/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc
index 1409d99ea863..b8f4575f7134 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix.cc
@@ -321,53 +321,6 @@ const char *DescribeSignalOrException(int signo) {
   return "UNKNOWN SIGNAL";
 }
 
-#if !SANITIZER_GO
-bool IsStackOverflow(int code, const SignalContext &sig) {
-  // Access at a reasonable offset above SP, or slightly below it (to account
-  // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
-  // probably a stack overflow.
-#ifdef __s390__
-  // On s390, the fault address in siginfo points to start of the page, not
-  // to the precise word that was accessed.  Mask off the low bits of sp to
-  // take it into account.
-  bool IsStackAccess =
-      sig.addr >= (sig.sp & ~0xFFF) && sig.addr < sig.sp + 0xFFFF;
-#else
-  bool IsStackAccess = sig.addr + 512 > sig.sp && sig.addr < sig.sp + 0xFFFF;
-#endif
-
-#if __powerpc__
-  // Large stack frames can be allocated with e.g.
-  //   lis r0,-10000
-  //   stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
-  // If the store faults then sp will not have been updated, so test above
-  // will not work, because the fault address will be more than just "slightly"
-  // below sp.
-  if (!IsStackAccess && IsAccessibleMemoryRange(sig.pc, 4)) {
-    u32 inst = *(unsigned *)sig.pc;
-    u32 ra = (inst >> 16) & 0x1F;
-    u32 opcd = inst >> 26;
-    u32 xo = (inst >> 1) & 0x3FF;
-    // Check for store-with-update to sp. The instructions we accept are:
-    //   stbu rs,d(ra)          stbux rs,ra,rb
-    //   sthu rs,d(ra)          sthux rs,ra,rb
-    //   stwu rs,d(ra)          stwux rs,ra,rb
-    //   stdu rs,ds(ra)         stdux rs,ra,rb
-    // where ra is r1 (the stack pointer).
-    if (ra == 1 &&
-        (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
-         (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
-      IsStackAccess = true;
-  }
-#endif  // __powerpc__
-
-  // We also check si_code to filter out SEGV caused by something else other
-  // then hitting the guard page or unmapped memory, like, for example,
-  // unaligned memory access.
-  return IsStackAccess && (code == si_SEGV_MAPERR || code == si_SEGV_ACCERR);
-}
-#endif  //! SANITIZER_GO
-
 } // namespace __sanitizer
 
 #endif // SANITIZER_POSIX
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc
index 13062f0004e4..5ff71b4e23d6 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc
@@ -215,6 +215,51 @@ void InstallDeadlySignalHandlers(SignalHandlerType handler) {
   MaybeInstallSigaction(SIGFPE, handler);
   MaybeInstallSigaction(SIGILL, handler);
 }
+bool IsStackOverflow(int code, const SignalContext &sig) {
+  // Access at a reasonable offset above SP, or slightly below it (to account
+  // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
+  // probably a stack overflow.
+#ifdef __s390__
+  // On s390, the fault address in siginfo points to start of the page, not
+  // to the precise word that was accessed.  Mask off the low bits of sp to
+  // take it into account.
+  bool IsStackAccess =
+      sig.addr >= (sig.sp & ~0xFFF) && sig.addr < sig.sp + 0xFFFF;
+#else
+  bool IsStackAccess = sig.addr + 512 > sig.sp && sig.addr < sig.sp + 0xFFFF;
+#endif
+
+#if __powerpc__
+  // Large stack frames can be allocated with e.g.
+  //   lis r0,-10000
+  //   stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
+  // If the store faults then sp will not have been updated, so test above
+  // will not work, because the fault address will be more than just "slightly"
+  // below sp.
+  if (!IsStackAccess && IsAccessibleMemoryRange(sig.pc, 4)) {
+    u32 inst = *(unsigned *)sig.pc;
+    u32 ra = (inst >> 16) & 0x1F;
+    u32 opcd = inst >> 26;
+    u32 xo = (inst >> 1) & 0x3FF;
+    // Check for store-with-update to sp. The instructions we accept are:
+    //   stbu rs,d(ra)          stbux rs,ra,rb
+    //   sthu rs,d(ra)          sthux rs,ra,rb
+    //   stwu rs,d(ra)          stwux rs,ra,rb
+    //   stdu rs,ds(ra)         stdux rs,ra,rb
+    // where ra is r1 (the stack pointer).
+    if (ra == 1 &&
+        (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
+         (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
+      IsStackAccess = true;
+  }
+#endif  // __powerpc__
+
+  // We also check si_code to filter out SEGV caused by something else other
+  // then hitting the guard page or unmapped memory, like, for example,
+  // unaligned memory access.
+  return IsStackAccess && (code == si_SEGV_MAPERR || code == si_SEGV_ACCERR);
+}
+
 #endif  // SANITIZER_GO
 
 bool IsAccessibleMemoryRange(uptr beg, uptr size) {