[windows] Fix out-of-memory failure in some of the tests

Summary: When ReadProcessMemory fails, bytes_read is sometimes set to a large garbage value. In that case, we need to set it back to zero before returning or the garbage value will be used to allocate memory later causing LLDB to crash with an out of memory error.

Reviewers: asmith, zturner

Reviewed By: zturner

Subscribers: zturner, asmith, stella.stamenova, llvm-commits

Differential Revision: https://reviews.llvm.org/D49159

llvm-svn: 336865

lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp

@@ -240,7 +240,7 @@ Status ProcessWindows::DoLaunch(Module *exe_module,
   if (working_dir && (!working_dir.ResolvePath() ||
                       !fs::is_directory(working_dir.GetPath()))) {
     result.SetErrorStringWithFormat("No such file or directory: %s",
-                                   working_dir.GetCString());
+                                    working_dir.GetCString());
     return result;
   }
 
@@ -365,7 +365,10 @@ Status ProcessWindows::DoResume() {
       Status result = thread->DoResume();
       if (result.Fail()) {
         failed = true;
-        LLDB_LOG(log, "Trying to resume thread at index {0}, but failed with error {1}.", i, result);
+        LLDB_LOG(
+            log,
+            "Trying to resume thread at index {0}, but failed with error {1}.",
+            i, result);
       }
     }
 
@@ -473,8 +476,9 @@ void ProcessWindows::RefreshStateAfterStop() {
       m_session_data->m_debugger->GetActiveException();
   ExceptionRecordSP active_exception = exception_record.lock();
   if (!active_exception) {
-    LLDB_LOG(log, "there is no active exception in process {0}.  Why is the "
-                  "process stopped?",
+    LLDB_LOG(log,
+             "there is no active exception in process {0}.  Why is the "
+             "process stopped?",
              m_session_data->m_debugger->GetProcess().GetProcessId());
     return;
   }
@@ -491,8 +495,9 @@ void ProcessWindows::RefreshStateAfterStop() {
     const uint64_t pc = register_context->GetPC();
     BreakpointSiteSP site(GetBreakpointSiteList().FindByAddress(pc));
     if (site && site->ValidForThisThread(stop_thread.get())) {
-      LLDB_LOG(log, "Single-stepped onto a breakpoint in process {0} at "
-                    "address {1:x} with breakpoint site {2}",
+      LLDB_LOG(log,
+               "Single-stepped onto a breakpoint in process {0} at "
+               "address {1:x} with breakpoint site {2}",
                m_session_data->m_debugger->GetProcess().GetProcessId(), pc,
                site->GetID());
       stop_info = StopInfo::CreateStopReasonWithBreakpointSiteID(*stop_thread,
@@ -514,22 +519,25 @@ void ProcessWindows::RefreshStateAfterStop() {
 
     BreakpointSiteSP site(GetBreakpointSiteList().FindByAddress(pc));
     if (site) {
-      LLDB_LOG(log, "detected breakpoint in process {0} at address {1:x} with "
-                    "breakpoint site {2}",
+      LLDB_LOG(log,
+               "detected breakpoint in process {0} at address {1:x} with "
+               "breakpoint site {2}",
                m_session_data->m_debugger->GetProcess().GetProcessId(), pc,
                site->GetID());
 
       if (site->ValidForThisThread(stop_thread.get())) {
-        LLDB_LOG(log, "Breakpoint site {0} is valid for this thread ({1:x}), "
-                      "creating stop info.",
+        LLDB_LOG(log,
+                 "Breakpoint site {0} is valid for this thread ({1:x}), "
+                 "creating stop info.",
                  site->GetID(), stop_thread->GetID());
 
         stop_info = StopInfo::CreateStopReasonWithBreakpointSiteID(
             *stop_thread, site->GetID());
         register_context->SetPC(pc);
       } else {
-        LLDB_LOG(log, "Breakpoint site {0} is not valid for this thread, "
-                      "creating empty stop info.",
+        LLDB_LOG(log,
+                 "Breakpoint site {0} is not valid for this thread, "
+                 "creating empty stop info.",
                  site->GetID());
       }
       stop_thread->SetStopInfo(stop_info);
@@ -651,8 +659,13 @@ size_t ProcessWindows::DoReadMemory(lldb::addr_t vm_addr, void *buf,
   SIZE_T bytes_read = 0;
   if (!ReadProcessMemory(process.GetNativeProcess().GetSystemHandle(), addr,
                          buf, size, &bytes_read)) {
+    // Reading from the process can fail for a number of reasons - set the
+    // error code and make sure that the number of bytes read is set back to 0
+    // because in some scenarios the value of bytes_read returned from the API
+    // is garbage.
     error.SetError(GetLastError(), eErrorTypeWin32);
     LLDB_LOG(log, "reading failed with error: {0}", error);
+    bytes_read = 0;
   }
   return bytes_read;
 }
@@ -723,8 +736,9 @@ Status ProcessWindows::GetMemoryRegionInfo(lldb::addr_t vm_addr,
       return error;
     } else {
       error.SetError(::GetLastError(), eErrorTypeWin32);
-      LLDB_LOG(log, "VirtualQueryEx returned error {0} while getting memory "
-                    "region info for address {1:x}",
+      LLDB_LOG(log,
+               "VirtualQueryEx returned error {0} while getting memory "
+               "region info for address {1:x}",
                error, vm_addr);
       return error;
     }
@@ -765,8 +779,9 @@ Status ProcessWindows::GetMemoryRegionInfo(lldb::addr_t vm_addr,
   }
 
   error.SetError(::GetLastError(), eErrorTypeWin32);
-  LLDB_LOGV(log, "Memory region info for address {0}: readable={1}, "
-                 "executable={2}, writable={3}",
+  LLDB_LOGV(log,
+            "Memory region info for address {0}: readable={1}, "
+            "executable={2}, writable={3}",
             vm_addr, info.GetReadable(), info.GetExecutable(),
             info.GetWritable());
   return error;
@@ -857,8 +872,9 @@ ProcessWindows::OnDebugException(bool first_chance,
   // suite to print out full lldb logs, and then add logging to the process
   // plugin.
   if (!m_session_data) {
-    LLDB_LOG(log, "Debugger thread reported exception {0:x} at address {1:x}, "
-                  "but there is no session.",
+    LLDB_LOG(log,
+             "Debugger thread reported exception {0:x} at address {1:x}, "
+             "but there is no session.",
              record.GetExceptionCode(), record.GetExceptionAddress());
     return ExceptionResult::SendToApplication;
   }
@@ -892,8 +908,9 @@ ProcessWindows::OnDebugException(bool first_chance,
     SetPrivateState(eStateStopped);
     break;
   default:
-    LLDB_LOG(log, "Debugger thread reported exception {0:x} at address {1:x} "
-                  "(first_chance={2})",
+    LLDB_LOG(log,
+             "Debugger thread reported exception {0:x} at address {1:x} "
+             "(first_chance={2})",
              record.GetExceptionCode(), record.GetExceptionAddress(),
              first_chance);
     // For non-breakpoints, give the application a chance to handle the
@@ -967,8 +984,9 @@ void ProcessWindows::OnDebuggerError(const Status &error, uint32_t type) {
   if (m_session_data->m_initial_stop_received) {
     // This happened while debugging.  Do we shutdown the debugging session,
     // try to continue, or do something else?
-    LLDB_LOG(log, "Error {0} occurred during debugging.  Unexpected behavior "
-                  "may result.  {1}",
+    LLDB_LOG(log,
+             "Error {0} occurred during debugging.  Unexpected behavior "
+             "may result.  {1}",
              error.GetError(), error);
   } else {
     // If we haven't actually launched the process yet, this was an error