Large watchpoint use watchpointresources

lldb/include/lldb/Breakpoint/WatchpointAlgorithms.h

@@ -0,0 +1,103 @@
+//===-- WatchpointAlgorithms.h ----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_BREAKPOINT_WATCHPOINTALGORITHMS_H
+#define LLDB_BREAKPOINT_WATCHPOINTALGORITHMS_H
+
+#include "lldb/Breakpoint/WatchpointResource.h"
+#include "lldb/Utility/ArchSpec.h"
+#include "lldb/lldb-public.h"
+
+#include <vector>
+
+namespace lldb_private {
+
+class WatchpointAlgorithms {
+
+public:
+  /// Convert a user's watchpoint request into an array of memory
+  /// regions that can be watched by one hardware watchpoint register
+  /// on the current target.
+  ///
+  /// \param[in] addr
+  ///     The start address specified by the user.
+  ///
+  /// \param[in] size
+  ///     The number of bytes the user wants to watch.
+  ///
+  /// \param[in] read
+  ///     True if we are watching for read accesses.
+  ///
+  /// \param[in] write
+  ///     True if we are watching for write accesses.
+  ///     \a read and \a write may both be true.
+  ///     There is no "modify" style for WatchpointResources -
+  ///     WatchpointResources are akin to the hardware watchpoint
+  ///     registers which are either in terms of read or write.
+  ///     "modify" distinction is done at the Watchpoint layer, where
+  ///     we check the actual range of bytes the user requested.
+  ///
+  /// \param[in] supported_features
+  ///     The bit flags in this parameter are set depending on which
+  ///     WatchpointHardwareFeature enum values the current target supports.
+  ///     The eWatchpointHardwareFeatureUnknown bit may be set if we
+  ///     don't have specific information about what the remote stub
+  ///     can support, and a reasonablec default will be used.
+  ///
+  /// \param[in] arch
+  ///     The ArchSpec of the current Target.
+  ///
+  /// \return
+  ///     A vector of WatchpointResourceSP's, one per hardware watchpoint
+  ///     register needed.  We may return more WatchpointResources than the
+  ///     target can watch at once; if all resources cannot be set, the
+  ///     watchpoint cannot be set.
+  static std::vector<lldb::WatchpointResourceSP> AtomizeWatchpointRequest(
+      lldb::addr_t addr, size_t size, bool read, bool write,
+      lldb::WatchpointHardwareFeature supported_features, ArchSpec &arch);
+
+  struct Region {
+    lldb::addr_t addr;
+    size_t size;
+  };
+
+protected:
+  /// Convert a user's watchpoint request into an array of addr+size that
+  /// can be watched with power-of-2 style hardware watchpoints.
+  ///
+  /// This is the default algorithm if we have no further information;
+  /// most watchpoint implementations can be assumed to be able to watch up
+  /// to pointer-size regions of memory in power-of-2 sizes and alingments.
+  ///
+  /// \param[in] user_addr
+  ///     The user's start address.
+  ///
+  /// \param[in] user_size
+  ///     The user's specified byte length.
+  ///
+  /// \param[in] min_byte_size
+  ///     The minimum byte size supported on this target.
+  ///     In most cases, this will be 1.  AArch64 MASK watchpoints can
+  ///     watch a minimum of 8 bytes (although Byte Address Select watchpoints
+  ///     can watch 1 to pointer-size bytes in a pointer-size aligned granule).
+  ///
+  /// \param[in] max_byte_size
+  ///     The maximum byte size supported for one watchpoint on this target.
+  ///
+  /// \param[in] address_byte_size
+  ///     The address byte size on this target.
+  static std::vector<Region> PowerOf2Watchpoints(lldb::addr_t user_addr,
+                                                 size_t user_size,
+                                                 size_t min_byte_size,
+                                                 size_t max_byte_size,
+                                                 uint32_t address_byte_size);
+};
+
+} // namespace lldb_private
+
+#endif // LLDB_BREAKPOINT_WATCHPOINTALGORITHMS_H

lldb/include/lldb/Breakpoint/WatchpointResource.h

@@ -121,14 +121,6 @@ class WatchpointResource
   ///    A copy of the Watchpoints which own this resource.
   WatchpointCollection CopyConstituentsList();
 
-  // The ID of the WatchpointResource is set by the WatchpointResourceList
-  // when the Resource has been set in the inferior and is being added
-  // to the List, in an attempt to match the hardware watchpoint register
-  // ordering.  If a Process can correctly identify the hardware watchpoint
-  // register index when it has created the Resource, it may initialize it
-  // before it is inserted in the WatchpointResourceList.
-  void SetID(lldb::wp_resource_id_t);
-
   lldb::wp_resource_id_t GetID() const;
 
   bool Contains(lldb::addr_t addr);

lldb/include/lldb/lldb-enumerations.h

@@ -448,6 +448,32 @@ enum WatchpointWriteType {
   eWatchpointWriteTypeOnModify
 };
 
+/// The hardware and native stub capabilities for a given target,
+/// for translating a user's watchpoint request into hardware
+/// capable watchpoint resources.
+FLAGS_ENUM(WatchpointHardwareFeature){
+    /// lldb will fall back to a default that assumes the target
+    /// can watch up to pointer-size power-of-2 regions, aligned to
+    /// power-of-2.
+    eWatchpointHardwareFeatureUnknown = (1u << 0),
+
+    /// Intel systems can watch 1, 2, 4, or 8 bytes (in 64-bit targets),
+    /// aligned naturally.
+    eWatchpointHardwareX86 = (1u << 1),
+
+    /// ARM systems with Byte Address Select watchpoints
+    /// can watch any consecutive series of bytes up to the
+    /// size of a pointer (4 or 8 bytes), at a pointer-size
+    /// alignment.
+    eWatchpointHardwareArmBAS = (1u << 2),
+
+    /// ARM systems with MASK watchpoints can watch any power-of-2
+    /// sized region from 8 bytes to 2 gigabytes, aligned to that
+    /// same power-of-2 alignment.
+    eWatchpointHardwareArmMASK = (1u << 3),
+};
+LLDB_MARK_AS_BITMASK_ENUM(WatchpointHardwareFeature)
+
 /// Programming language type.
 ///
 /// These enumerations use the same language enumerations as the DWARF

lldb/packages/Python/lldbsuite/test/concurrent_base.py

@@ -166,7 +166,12 @@ def do_thread_actions(
 
         # Initialize the (single) watchpoint on the global variable (g_watchme)
         if num_watchpoint_threads + num_delay_watchpoint_threads > 0:
-            self.runCmd("watchpoint set variable g_watchme")
+            # The concurrent tests have multiple threads modifying a variable
+            # with the same value.  The default "modify" style watchpoint will
+            # only report this as 1 hit for all threads, because they all wrote
+            # the same value.  The testsuite needs "write" style watchpoints to
+            # get the correct number of hits reported.
+            self.runCmd("watchpoint set variable -w write g_watchme")
             for w in self.inferior_target.watchpoint_iter():
                 self.thread_watchpoint = w
                 self.assertTrue(

lldb/source/Breakpoint/CMakeLists.txt

@@ -21,10 +21,10 @@ add_lldb_library(lldbBreakpoint NO_PLUGIN_DEPENDENCIES
   StoppointSite.cpp
   StopPointSiteList.cpp
   Watchpoint.cpp
+  WatchpointAlgorithms.cpp
   WatchpointList.cpp
   WatchpointOptions.cpp
   WatchpointResource.cpp
-  WatchpointResourceList.cpp
 
   LINK_LIBS
     lldbCore

lldb/source/Breakpoint/Watchpoint.cpp

@@ -45,10 +45,16 @@ Watchpoint::Watchpoint(Target &target, lldb::addr_t addr, uint32_t size,
       LLDB_LOG_ERROR(GetLog(LLDBLog::Watchpoints), std::move(err),
                      "Failed to set type: {0}");
     } else {
-      if (auto ts = *type_system_or_err)
-        m_type =
-            ts->GetBuiltinTypeForEncodingAndBitSize(eEncodingUint, 8 * size);
-      else
+      if (auto ts = *type_system_or_err) {
+        if (size <= target.GetArchitecture().GetAddressByteSize()) {
+          m_type =
+              ts->GetBuiltinTypeForEncodingAndBitSize(eEncodingUint, 8 * size);
+        } else {
+          CompilerType clang_uint8_type =
+              ts->GetBuiltinTypeForEncodingAndBitSize(eEncodingUint, 8);
+          m_type = clang_uint8_type.GetArrayType(size);
+        }
+      } else
         LLDB_LOG_ERROR(GetLog(LLDBLog::Watchpoints), std::move(err),
                        "Failed to set type: Typesystem is no longer live: {0}");
     }
@@ -352,6 +358,20 @@ void Watchpoint::DumpWithLevel(Stream *s,
       s->Printf("\n    declare @ '%s'", m_decl_str.c_str());
     if (!m_watch_spec_str.empty())
       s->Printf("\n    watchpoint spec = '%s'", m_watch_spec_str.c_str());
+    if (IsEnabled()) {
+      if (ProcessSP process_sp = m_target.GetProcessSP()) {
+        auto &resourcelist = process_sp->GetWatchpointResourceList();
+        size_t idx = 0;
+        s->Printf("\n    watchpoint resources:");
+        for (WatchpointResourceSP &wpres : resourcelist.Sites()) {
+          if (wpres->ConstituentsContains(this)) {
+            s->Printf("\n       #%zu: ", idx);
+            wpres->Dump(s);
+          }
+          idx++;
+        }
+      }
+    }
 
     // Dump the snapshots we have taken.
     DumpSnapshots(s, "    ");