Add bound violation handling for Intel(R) Memory Protection Extensions (Intel(R) MPX)

Summary:
This patch adds support for handling the SIGSEGV signal with 'si_code ==
SEGV_BNDERR', which is thrown when a bound violation is caught by the
Intel(R) MPX technology.

Differential Revision: https://reviews.llvm.org/D25329

llvm-svn: 283474

1 files changed, 39 insertions, 3 deletions

diff --git a/lldb/source/Plugins/Process/POSIX/CrashReason.cpp b/lldb/source/Plugins/Process/POSIX/CrashReason.cpp
index c567b4a9655..a7d36fc998e 100644
--- a/lldb/source/Plugins/Process/POSIX/CrashReason.cpp
+++ b/lldb/source/Plugins/Process/POSIX/CrashReason.cpp
@@ -9,6 +9,8 @@
 
 #include "CrashReason.h"
 
+#include "llvm/Support/raw_ostream.h"
+
 #include <sstream>
 
 namespace {
@@ -19,6 +21,23 @@ void AppendFaultAddr(std::string &str, lldb::addr_t addr) {
   str += ss.str();
 }
 
+void AppendBounds(std::string &str, lldb::addr_t lower_bound,
+                  lldb::addr_t upper_bound, lldb::addr_t addr) {
+  llvm::raw_string_ostream stream(str);
+  if ((unsigned long)addr < lower_bound)
+    stream << ": lower bound violation ";
+  else
+    stream << ": upper bound violation ";
+  stream << "(fault address: 0x";
+  stream.write_hex(addr);
+  stream << ", lower bound: 0x";
+  stream.write_hex(lower_bound);
+  stream << ", upper bound: 0x";
+  stream.write_hex(upper_bound);
+  stream << ")";
+  stream.flush();
+}
+
 CrashReason GetCrashReasonForSIGSEGV(const siginfo_t &info) {
   assert(info.si_signo == SIGSEGV);
 
@@ -34,6 +53,11 @@ CrashReason GetCrashReasonForSIGSEGV(const siginfo_t &info) {
     return CrashReason::eInvalidAddress;
   case SEGV_ACCERR:
     return CrashReason::ePrivilegedAddress;
+#ifndef SEGV_BNDERR
+#define SEGV_BNDERR 3
+#endif
+  case SEGV_BNDERR:
+    return CrashReason::eBoundViolation;
   }
 
   assert(false && "unexpected si_code for SIGSEGV");
@@ -109,7 +133,7 @@ CrashReason GetCrashReasonForSIGBUS(const siginfo_t &info) {
 }
 }
 
-std::string GetCrashReasonString(CrashReason reason, lldb::addr_t fault_addr) {
+std::string GetCrashReasonString(CrashReason reason, const siginfo_t &info) {
   std::string str;
 
   switch (reason) {
@@ -119,11 +143,20 @@ std::string GetCrashReasonString(CrashReason reason, lldb::addr_t fault_addr) {
 
   case CrashReason::eInvalidAddress:
     str = "signal SIGSEGV: invalid address";
-    AppendFaultAddr(str, fault_addr);
+    AppendFaultAddr(str, reinterpret_cast<lldb::addr_t>(info.si_addr));
     break;
   case CrashReason::ePrivilegedAddress:
     str = "signal SIGSEGV: address access protected";
-    AppendFaultAddr(str, fault_addr);
+    AppendFaultAddr(str, reinterpret_cast<lldb::addr_t>(info.si_addr));
+    break;
+  case CrashReason::eBoundViolation:
+    str = "signal SIGSEGV";
+// Make sure that siginfo_t has the bound fields available.
+#if defined(si_lower) && defined(si_upper)
+    AppendBounds(str, reinterpret_cast<lldb::addr_t>(info.si_lower),
+                     reinterpret_cast<lldb::addr_t>(info.si_upper),
+                     reinterpret_cast<lldb::addr_t>(info.si_addr));
+#endif
     break;
   case CrashReason::eIllegalOpcode:
     str = "signal SIGILL: illegal instruction";
@@ -207,6 +240,9 @@ const char *CrashReasonAsString(CrashReason reason) {
   case CrashReason::ePrivilegedAddress:
     str = "ePrivilegedAddress";
     break;
+  case CrashReason::eBoundViolation:
+    str = "eBoundViolation";
+    break;
 
   // SIGILL crash reasons.
   case CrashReason::eIllegalOpcode: