Move dead submodules in-tree

Signed-off-by: swurl <swurl@swurl.xyz>

externals/breakpad/src/google_breakpad/processor/stackwalker.h

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+// Copyright 2010 Google LLC
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google LLC nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// stackwalker.h: Generic stackwalker.
+//
+// The Stackwalker class is an abstract base class providing common generic
+// methods that apply to stacks from all systems.  Specific implementations
+// will extend this class by providing GetContextFrame and GetCallerFrame
+// methods to fill in system-specific data in a StackFrame structure.
+// Stackwalker assembles these StackFrame strucutres into a CallStack.
+//
+// Author: Mark Mentovai
+
+
+#ifndef GOOGLE_BREAKPAD_PROCESSOR_STACKWALKER_H__
+#define GOOGLE_BREAKPAD_PROCESSOR_STACKWALKER_H__
+
+#include <set>
+#include <string>
+#include <vector>
+
+#include "common/using_std_string.h"
+#include "google_breakpad/common/breakpad_types.h"
+#include "google_breakpad/processor/code_modules.h"
+#include "google_breakpad/processor/memory_region.h"
+#include "google_breakpad/processor/stack_frame_symbolizer.h"
+
+namespace google_breakpad {
+
+class CallStack;
+class DumpContext;
+class StackFrameSymbolizer;
+
+using std::set;
+using std::vector;
+
+class Stackwalker {
+ public:
+  virtual ~Stackwalker() {}
+
+  // Populates the given CallStack by calling GetContextFrame and
+  // GetCallerFrame.  The frames are further processed to fill all available
+  // data.  Returns true if the stackwalk completed, or false if it was
+  // interrupted by SymbolSupplier::GetSymbolFile().
+  // Upon return, |modules_without_symbols| will be populated with pointers to
+  // the code modules (CodeModule*) that DON'T have symbols.
+  // |modules_with_corrupt_symbols| will be populated with pointers to the
+  // modules which have corrupt symbols.  |modules_without_symbols| and
+  // |modules_with_corrupt_symbols| DO NOT take ownership of the code modules.
+  // The lifetime of these code modules is the same as the lifetime of the
+  // CodeModules passed to the StackWalker constructor (which currently
+  // happens to be the lifetime of the Breakpad's ProcessingState object).
+  // There is a check for duplicate modules so no duplicates are expected.
+  bool Walk(CallStack* stack,
+            vector<const CodeModule*>* modules_without_symbols,
+            vector<const CodeModule*>* modules_with_corrupt_symbols);
+
+  // Returns a new concrete subclass suitable for the CPU that a stack was
+  // generated on, according to the CPU type indicated by the context
+  // argument.  If no suitable concrete subclass exists, returns NULL.
+  static Stackwalker* StackwalkerForCPU(
+     const SystemInfo* system_info,
+     DumpContext* context,
+     MemoryRegion* memory,
+     const CodeModules* modules,
+     const CodeModules* unloaded_modules,
+     StackFrameSymbolizer* resolver_helper);
+
+
+  static void set_max_frames(uint32_t max_frames) {
+    max_frames_ = max_frames;
+    max_frames_set_ = true;
+  }
+  static uint32_t max_frames() { return max_frames_; }
+
+  static void set_max_frames_scanned(uint32_t max_frames_scanned) {
+    max_frames_scanned_ = max_frames_scanned;
+  }
+
+ protected:
+  // system_info identifies the operating system, NULL or empty if unknown.
+  // memory identifies a MemoryRegion that provides the stack memory
+  // for the stack to walk.  modules, if non-NULL, is a CodeModules
+  // object that is used to look up which code module each stack frame is
+  // associated with.  frame_symbolizer is a StackFrameSymbolizer object that
+  // encapsulates the logic of how source line resolver interacts with symbol
+  // supplier to symbolize stack frame and look up caller frame information
+  // (see stack_frame_symbolizer.h).
+  // frame_symbolizer MUST NOT be NULL (asserted).
+  Stackwalker(const SystemInfo* system_info,
+              MemoryRegion* memory,
+              const CodeModules* modules,
+              StackFrameSymbolizer* frame_symbolizer);
+
+  // This can be used to filter out potential return addresses when
+  // the stack walker resorts to stack scanning.
+  // Returns true if any of:
+  // * This address is within a loaded module, but we don't have symbols
+  //   for that module.
+  // * This address is within a loaded module for which we have symbols,
+  //   and falls inside a function in that module.
+  // Returns false otherwise.
+  bool InstructionAddressSeemsValid(uint64_t address) const;
+
+  // Checks whether we should stop the stack trace.
+  // (either we reached the end-of-stack or we detected a
+  //  broken callstack invariant)
+  bool TerminateWalk(uint64_t caller_ip,
+                     uint64_t caller_sp,
+                     uint64_t callee_sp,
+                     bool first_unwind) const;
+
+  // The default number of words to search through on the stack
+  // for a return address.
+  static const int kRASearchWords;
+
+  template<typename InstructionType>
+  bool ScanForReturnAddress(InstructionType location_start,
+                            InstructionType* location_found,
+                            InstructionType* ip_found,
+                            bool is_context_frame) {
+    // When searching for the caller of the context frame,
+    // allow the scanner to look farther down the stack.
+    const int search_words = is_context_frame ?
+      kRASearchWords * 4 :
+      kRASearchWords;
+
+    return ScanForReturnAddress(location_start, location_found, ip_found,
+                                search_words);
+  }
+
+  // Scan the stack starting at location_start, looking for an address
+  // that looks like a valid instruction pointer. Addresses must
+  // 1) be contained in the current stack memory
+  // 2) pass the checks in InstructionAddressSeemsValid
+  //
+  // Returns true if a valid-looking instruction pointer was found.
+  // When returning true, sets location_found to the address at which
+  // the value was found, and ip_found to the value contained at that
+  // location in memory.
+  template<typename InstructionType>
+  bool ScanForReturnAddress(InstructionType location_start,
+                            InstructionType* location_found,
+                            InstructionType* ip_found,
+                            int searchwords) {
+    for (InstructionType location = location_start;
+         location <= location_start + searchwords * sizeof(InstructionType);
+         location += sizeof(InstructionType)) {
+      InstructionType ip;
+      if (!memory_->GetMemoryAtAddress(location, &ip))
+        break;
+
+      // The return address points to the instruction after a call. If the
+      // caller was a no return function, this might point past the end of the
+      // function. Subtract one from the instruction pointer so it points into
+      // the call instruction instead.
+      if (modules_ && modules_->GetModuleForAddress(ip  - 1) &&
+          InstructionAddressSeemsValid(ip - 1)) {
+        *ip_found = ip;
+        *location_found = location;
+        return true;
+      }
+    }
+    // nothing found
+    return false;
+  }
+
+  // Information about the system that produced the minidump.  Subclasses
+  // and the SymbolSupplier may find this information useful.
+  const SystemInfo* system_info_;
+
+  // The stack memory to walk.  Subclasses will require this region to
+  // get information from the stack.
+  MemoryRegion* memory_;
+
+  // A list of modules, for populating each StackFrame's module information.
+  // This field is optional and may be NULL.
+  const CodeModules* modules_;
+
+  // A list of unloaded modules, for populating frames which aren't matched
+  // to any loaded modules.
+  // This field is optional and may be NULL.
+  const CodeModules* unloaded_modules_;
+
+ protected:
+  // The StackFrameSymbolizer implementation.
+  StackFrameSymbolizer* frame_symbolizer_;
+
+ private:
+  // Obtains the context frame, the innermost called procedure in a stack
+  // trace.  Returns NULL on failure.  GetContextFrame allocates a new
+  // StackFrame (or StackFrame subclass), ownership of which is taken by
+  // the caller.
+  virtual StackFrame* GetContextFrame() = 0;
+
+  // Obtains a caller frame.  Each call to GetCallerFrame should return the
+  // frame that called the last frame returned by GetContextFrame or
+  // GetCallerFrame.  To aid this purpose, stack contains the CallStack
+  // made of frames that have already been walked.  GetCallerFrame should
+  // return NULL on failure or when there are no more caller frames (when
+  // the end of the stack has been reached).  GetCallerFrame allocates a new
+  // StackFrame (or StackFrame subclass), ownership of which is taken by
+  // the caller.  |stack_scan_allowed| controls whether stack scanning is
+  // an allowable frame-recovery method, since it is desirable to be able to
+  // disable stack scanning in performance-critical use cases.
+  //
+  // CONSIDER: a way to differentiate between:
+  //  - full stack traces
+  //  - explicitly truncated traces (max_frames_)
+  //  - stopping after max scanned frames
+  //  - failed stack walk (breaking one of the stack walk invariants)
+  //
+  virtual StackFrame* GetCallerFrame(const CallStack* stack,
+                                     bool stack_scan_allowed) = 0;
+
+  // The maximum number of frames Stackwalker will walk through.
+  // This defaults to 1024 to prevent infinite loops.
+  static uint32_t max_frames_;
+
+  // Keep track of whether max_frames_ has been set by the user, since
+  // it affects whether or not an error message is printed in the case
+  // where an unwind got stopped by the limit.
+  static bool max_frames_set_;
+
+  // The maximum number of stack-scanned and otherwise untrustworthy
+  // frames allowed.  Stack-scanning can be expensive, so the option to
+  // disable or limit it is helpful in cases where unwind performance is
+  // important.  This defaults to 1024, the same as max_frames_.
+  static uint32_t max_frames_scanned_;
+};
+
+}  // namespace google_breakpad
+
+
+#endif  // GOOGLE_BREAKPAD_PROCESSOR_STACKWALKER_H__