[compiler-rt] Add siginfo into SignalContext

Summary:
Information stored there is often been passed along with SignalContext.

Part of https://github.com/google/sanitizers/issues/637

Reviewers: eugenis, alekseyshl

Subscribers: kubamracek, llvm-commits, dberris

Differential Revision: https://reviews.llvm.org/D37792

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@313167 91177308-0d34-0410-b5e6-96231b3b80d8

8 files changed, 38 insertions, 17 deletions

diff --git a/lib/asan/asan_errors.h b/lib/asan/asan_errors.h
index 9a1249244..55b8360a3 100644
--- a/lib/asan/asan_errors.h
+++ b/lib/asan/asan_errors.h
@@ -57,14 +57,14 @@ struct ErrorDeadlySignal : ErrorBase {
   // VS2013 doesn't implement unrestricted unions, so we need a trivial default
   // constructor
   ErrorDeadlySignal() = default;
-  ErrorDeadlySignal(u32 tid, const SignalContext &sig, int signo_)
+  ErrorDeadlySignal(u32 tid, const SignalContext &sig)
       : ErrorBase(tid),
         addr(sig.addr),
         pc(sig.pc),
         bp(sig.bp),
         sp(sig.sp),
         context(sig.context),
-        signo(signo_),
+        signo(sig.GetType()),
         write_flag(sig.write_flag),
         is_memory_access(sig.is_memory_access) {
     scariness.Clear();
diff --git a/lib/asan/asan_posix.cc b/lib/asan/asan_posix.cc
index 8f788bd13..497af02d7 100644
--- a/lib/asan/asan_posix.cc
+++ b/lib/asan/asan_posix.cc
@@ -37,10 +37,10 @@ void AsanOnDeadlySignal(int signo, void *siginfo, void *context) {
   ScopedDeadlySignal signal_scope(GetCurrentThread());
   StartReportDeadlySignal();
   SignalContext sig = SignalContext::Create(siginfo, context);
-  if (IsStackOverflow(((siginfo_t *)siginfo)->si_code, sig))
+  if (IsStackOverflow(sig))
     ReportStackOverflow(sig);
   else
-    ReportDeadlySignal(signo, sig);
+    ReportDeadlySignal(sig);
 }
 
 // ---------------------- TSD ---------------- {{{1
diff --git a/lib/asan/asan_report.cc b/lib/asan/asan_report.cc
index 312dcaeae..6055304e8 100644
--- a/lib/asan/asan_report.cc
+++ b/lib/asan/asan_report.cc
@@ -266,9 +266,9 @@ void ReportStackOverflow(const SignalContext &sig) {
   in_report.ReportError(error);
 }
 
-void ReportDeadlySignal(int signo, const SignalContext &sig) {
+void ReportDeadlySignal(const SignalContext &sig) {
   ScopedInErrorReport in_report(/*fatal*/ true);
-  ErrorDeadlySignal error(GetCurrentTidOrInvalid(), sig, signo);
+  ErrorDeadlySignal error(GetCurrentTidOrInvalid(), sig);
   in_report.ReportError(error);
 }
 
diff --git a/lib/asan/asan_report.h b/lib/asan/asan_report.h
index 5a3533a31..259177bc7 100644
--- a/lib/asan/asan_report.h
+++ b/lib/asan/asan_report.h
@@ -47,7 +47,7 @@ bool ParseFrameDescription(const char *frame_descr,
 void ReportGenericError(uptr pc, uptr bp, uptr sp, uptr addr, bool is_write,
                         uptr access_size, u32 exp, bool fatal);
 void ReportStackOverflow(const SignalContext &sig);
-void ReportDeadlySignal(int signo, const SignalContext &sig);
+void ReportDeadlySignal(const SignalContext &sig);
 void ReportNewDeleteSizeMismatch(uptr addr, uptr delete_size,
                                  BufferedStackTrace *free_stack);
 void ReportDoubleFree(uptr addr, BufferedStackTrace *free_stack);
diff --git a/lib/sanitizer_common/sanitizer_common.h b/lib/sanitizer_common/sanitizer_common.h
index d2021a0c9..32fd381cc 100644
--- a/lib/sanitizer_common/sanitizer_common.h
+++ b/lib/sanitizer_common/sanitizer_common.h
@@ -312,7 +312,7 @@ void InstallDeadlySignalHandlers(SignalHandlerType handler);
 const char *DescribeSignalOrException(int signo);
 // Signal reporting.
 void StartReportDeadlySignal();
-bool IsStackOverflow(int code, const SignalContext &sig);
+bool IsStackOverflow(const SignalContext &sig);
 // FIXME: Hide after moving more signal handling code into common.
 void MaybeReportNonExecRegion(uptr pc);
 void MaybeDumpInstructionBytes(uptr pc);
@@ -795,6 +795,7 @@ static inline void SanitizerBreakOptimization(void *arg) {
 }
 
 struct SignalContext {
+  void *siginfo;
   void *context;
   uptr addr;
   uptr pc;
@@ -804,9 +805,12 @@ struct SignalContext {
 
   enum WriteFlag { UNKNOWN, READ, WRITE } write_flag;
 
-  SignalContext(void *context, uptr addr, uptr pc, uptr sp, uptr bp,
-                bool is_memory_access, WriteFlag write_flag)
-      : context(context),
+  // SignalContext is going to keep pointers to siginfo and context without
+  // owning them.
+  SignalContext(void *siginfo, void *context, uptr addr, uptr pc, uptr sp,
+                uptr bp, bool is_memory_access, WriteFlag write_flag)
+      : siginfo(siginfo),
+        context(context),
         addr(addr),
         pc(pc),
         sp(sp),
@@ -821,6 +825,12 @@ struct SignalContext {
 
   // Returns true if the "context" indicates a memory write.
   static WriteFlag GetWriteFlag(void *context);
+
+  // Type of signal e.g. SIGSEGV or EXCEPTION_ACCESS_VIOLATION.
+  int GetType() const;
+
+  // String description of the signal.
+  const char *Describe() const { return DescribeSignalOrException(GetType()); }
 };
 
 void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp);
diff --git a/lib/sanitizer_common/sanitizer_posix.cc b/lib/sanitizer_common/sanitizer_posix.cc
index b8f4575f7..b74b1f995 100644
--- a/lib/sanitizer_common/sanitizer_posix.cc
+++ b/lib/sanitizer_common/sanitizer_posix.cc
@@ -296,13 +296,18 @@ bool GetCodeRangeForFile(const char *module, uptr *start, uptr *end) {
 }
 
 SignalContext SignalContext::Create(void *siginfo, void *context) {
-  auto si = (siginfo_t *)siginfo;
+  auto si = static_cast<const siginfo_t *>(siginfo);
   uptr addr = (uptr)si->si_addr;
   uptr pc, sp, bp;
   GetPcSpBp(context, &pc, &sp, &bp);
   WriteFlag write_flag = GetWriteFlag(context);
   bool is_memory_access = si->si_signo == SIGSEGV;
-  return SignalContext(context, addr, pc, sp, bp, is_memory_access, write_flag);
+  return SignalContext(siginfo, context, addr, pc, sp, bp, is_memory_access,
+                       write_flag);
+}
+
+int SignalContext::GetType() const {
+  return static_cast<const siginfo_t *>(siginfo)->si_signo;
 }
 
 const char *DescribeSignalOrException(int signo) {
diff --git a/lib/sanitizer_common/sanitizer_posix_libcdep.cc b/lib/sanitizer_common/sanitizer_posix_libcdep.cc
index d7d0e7d44..e49101a7b 100644
--- a/lib/sanitizer_common/sanitizer_posix_libcdep.cc
+++ b/lib/sanitizer_common/sanitizer_posix_libcdep.cc
@@ -215,7 +215,7 @@ void InstallDeadlySignalHandlers(SignalHandlerType handler) {
   MaybeInstallSigaction(SIGILL, handler);
 }
 
-bool IsStackOverflow(int code, const SignalContext &sig) {
+bool IsStackOverflow(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.
@@ -257,7 +257,9 @@ bool IsStackOverflow(int code, const SignalContext &sig) {
   // 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);
+  auto si = static_cast<const siginfo_t *>(sig.siginfo);
+  return IsStackAccess &&
+         (si->si_code == si_SEGV_MAPERR || si->si_code == si_SEGV_ACCERR);
 }
 
 void StartReportDeadlySignal() {
diff --git a/lib/sanitizer_common/sanitizer_win.cc b/lib/sanitizer_common/sanitizer_win.cc
index a13a4c5a5..65898a709 100644
--- a/lib/sanitizer_common/sanitizer_win.cc
+++ b/lib/sanitizer_common/sanitizer_win.cc
@@ -966,14 +966,18 @@ SignalContext SignalContext::Create(void *siginfo, void *context) {
   case 8: write_flag = SignalContext::UNKNOWN; break;
   }
   bool is_memory_access = write_flag != SignalContext::UNKNOWN;
-  return SignalContext(context, access_addr, pc, sp, bp, is_memory_access,
-                       write_flag);
+  return SignalContext(siginfo, context, access_addr, pc, sp, bp,
+                       is_memory_access, write_flag);
 }
 
 void SignalContext::DumpAllRegisters(void *context) {
   // FIXME: Implement this.
 }
 
+int SignalContext::GetType() const {
+  return static_cast<const EXCEPTION_RECORD *>(siginfo)->ExceptionCode;
+}
+
 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
   // FIXME: Actually implement this function.
   CHECK_GT(buf_len, 0);