[ASan] Report illegal instruction exceptions in ASan

[rnk]

Summary

Respect the handle_sigill common flag and handle_segv flags while we're
at it.

We still handle signals/exceptions differently on Unix and Windows. The
installation process is tricky on Windows, and difficult to push down
into sanitizer_common without concerning it with the different
static/dynamic CRT models on Windows.

lib/asan/asan_win.cc

#if SANITIZER_WINDOWS64
   // On Win64, we map memory on demand with access violation handler.
   // Install our exception handler.
   CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler));
 #endif
 }
 
 static LPTOP_LEVEL_EXCEPTION_FILTER default_seh_handler;
 
+// Check based on flags if we should report this exception.
+static bool ShouldReportDeadlyException(unsigned code) {
+  switch (code) {
+    case EXCEPTION_ACCESS_VIOLATION:
+    case EXCEPTION_IN_PAGE_ERROR:
+      return common_flags()->handle_segv;
+    case EXCEPTION_BREAKPOINT:
+    case EXCEPTION_ILLEGAL_INSTRUCTION: {
+      return common_flags()->handle_sigill;
+    }
+  }
+  return false;
+}
+
+// Return the textual name for this exception.
+static const char *DescribeDeadlyException(unsigned code) {
+  switch (code) {
+    case EXCEPTION_ACCESS_VIOLATION:
+      return "access-violation";
+    case EXCEPTION_IN_PAGE_ERROR:
+      return "in-page-error";
+    case EXCEPTION_BREAKPOINT:
+      return "breakpoint";
+    case EXCEPTION_ILLEGAL_INSTRUCTION:
+      return "illegal-instruction";
+  }
+  return nullptr;
+}
+
 static long WINAPI SEHHandler(EXCEPTION_POINTERS *info) {
   EXCEPTION_RECORD *exception_record = info->ExceptionRecord;
   CONTEXT *context = info->ContextRecord;
 
-  if (exception_record->ExceptionCode == EXCEPTION_ACCESS_VIOLATION ||
-      exception_record->ExceptionCode == EXCEPTION_IN_PAGE_ERROR) {
+  if (ShouldReportDeadlyException(exception_record->ExceptionCode)) {
+    // Get the string description of the exception if this is a known deadly
+    // exception.
     const char *description =
-        (exception_record->ExceptionCode == EXCEPTION_ACCESS_VIOLATION)
-            ? "access-violation"
-            : "in-page-error";
+        DescribeDeadlyException(exception_record->ExceptionCode);
     SignalContext sig = SignalContext::Create(exception_record, context);
     ReportDeadlySignal(description, sig);
   }
 
   // FIXME: Handle EXCEPTION_STACK_OVERFLOW here.
 
   return default_seh_handler(info);
 }

test/asan/TestCases/ill.cc

+// Test the handle_sigill option.
+//
+// RUN: %clangxx_asan %s -o %t && %env_asan_opts=handle_sigill=0 not --crash %run %t 2>&1 | FileCheck %s --check-prefix=CHECK0
+// RUN: %clangxx_asan %s -o %t && %env_asan_opts=handle_sigill=1 not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK1
+
+int main() {
+  __builtin_trap();
+}
+// CHECK0-NOT: ERROR: AddressSanitizer
+// CHECK1: ERROR: AddressSanitizer: {{ILL|illegal-instruction}} on unknown address {{0x0*}}