[Lldb-commits] [lldb] r273863 - Allow unaligned byte/word selection watchpoints for arm- linux/android targets.

[Omair Javaid via lldb-commits]

Author: omjavaid
Date: Mon Jun 27 06:18:23 2016
New Revision: 273863

URL: http://llvm.org/viewvc/llvm-project?rev=273863&view=rev
Log:
Allow unaligned byte/word selection watchpoints for arm- linux/android targets.

Differential revision: http://reviews.llvm.org/D21516


Modified:
    lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm.cpp
    lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm.h
    lldb/trunk/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp

Modified: lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm.cpp?rev=273863&r1=273862&r2=273863&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm.cpp (original)
+++ lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm.cpp Mon Jun 27 06:18:23 2016
@@ -614,6 +614,7 @@ NativeRegisterContextLinux_arm::SetHardw
         return LLDB_INVALID_INDEX32;
 		
     uint32_t control_value = 0, wp_index = 0, addr_word_offset = 0, byte_mask = 0;
+    lldb::addr_t real_addr = addr;
 
     // Check if we are setting watchpoint other than read/write/access
     // Also update watchpoint flag to match Arm write-read bit configuration.
@@ -637,7 +638,24 @@ NativeRegisterContextLinux_arm::SetHardw
     if (size == 0 || size > 4)
         return LLDB_INVALID_INDEX32;
 
-    // We can only watch up to four bytes that follow a 4 byte aligned address
+    // Check 4-byte alignment for hardware watchpoint target address.
+    // Below is a hack to recalculate address and size in order to
+    // make sure we can watch non 4-byte alligned addresses as well.
+    if (addr & 0x03)
+    {
+        uint8_t watch_mask = (addr & 0x03) + size;
+
+        if (watch_mask > 0x04)
+            return LLDB_INVALID_INDEX32;
+        else if (watch_mask <= 0x02)
+            size = 2;
+        else if (watch_mask <= 0x04)
+            size = 4;
+
+        addr = addr & (~0x03);
+    }
+
+	// We can only watch up to four bytes that follow a 4 byte aligned address
     // per watchpoint register pair, so make sure we can properly encode this.
     addr_word_offset = addr % 4;
     byte_mask = ((1u << size) - 1u) << addr_word_offset;
@@ -682,6 +700,7 @@ NativeRegisterContextLinux_arm::SetHardw
     if ((m_hwp_regs[wp_index].control & 1) == 0)
     {
         // Update watchpoint in local cache
+        m_hwp_regs[wp_index].real_addr = real_addr;
         m_hwp_regs[wp_index].address = addr;
         m_hwp_regs[wp_index].control = control_value;
         m_hwp_regs[wp_index].refcount = 1;
@@ -864,6 +883,7 @@ NativeRegisterContextLinux_arm::GetWatch
         if (m_hwp_regs[wp_index].refcount >= 1 && WatchpointIsEnabled(wp_index)
             && trap_addr >= watch_addr && trap_addr < watch_addr + watch_size)
         {
+            m_hwp_regs[wp_index].hit_addr = trap_addr;
             return Error();
         }
     }
@@ -884,7 +904,24 @@ NativeRegisterContextLinux_arm::GetWatch
         return LLDB_INVALID_ADDRESS;
 
     if (WatchpointIsEnabled(wp_index))
-        return m_hwp_regs[wp_index].address;
+        return m_hwp_regs[wp_index].real_addr;
+    else
+        return LLDB_INVALID_ADDRESS;
+}
+
+lldb::addr_t
+NativeRegisterContextLinux_arm::GetWatchpointHitAddress (uint32_t wp_index)
+{
+    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_WATCHPOINTS));
+
+    if (log)
+        log->Printf ("NativeRegisterContextLinux_arm::%s()", __FUNCTION__);
+
+    if (wp_index >= m_max_hwp_supported)
+        return LLDB_INVALID_ADDRESS;
+
+    if (WatchpointIsEnabled(wp_index))
+        return m_hwp_regs[wp_index].hit_addr;
     else
         return LLDB_INVALID_ADDRESS;
 }

Modified: lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm.h?rev=273863&r1=273862&r2=273863&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm.h (original)
+++ lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm.h Mon Jun 27 06:18:23 2016
@@ -74,6 +74,9 @@ namespace process_linux {
         GetWatchpointHitIndex(uint32_t &wp_index, lldb::addr_t trap_addr) override;
 
         lldb::addr_t
+        GetWatchpointHitAddress (uint32_t wp_index) override;
+
+        lldb::addr_t
         GetWatchpointAddress (uint32_t wp_index) override;
 
         uint32_t
@@ -162,6 +165,8 @@ namespace process_linux {
         struct DREG
         {
             lldb::addr_t address;  // Breakpoint/watchpoint address value.
+            lldb::addr_t hit_addr; // Address at which last watchpoint trigger exception occurred.
+            lldb::addr_t real_addr;  // Address value that should cause target to stop.
             uint32_t control;  // Breakpoint/watchpoint control value.
             uint32_t refcount;  // Serves as enable/disable and refernce counter.
         };

Modified: lldb/trunk/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp?rev=273863&r1=273862&r2=273863&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp (original)
+++ lldb/trunk/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp Mon Jun 27 06:18:23 2016
@@ -2060,7 +2060,7 @@ ProcessGDBRemote::SetThreadStopInfo (lld
                                 WatchpointSP wp_sp;
                                 ArchSpec::Core core = GetTarget().GetArchitecture().GetCore();
                                 if ((core >= ArchSpec::kCore_mips_first && core <= ArchSpec::kCore_mips_last) ||
-                                    (core >= ArchSpec::eCore_arm_arm64 && core <= ArchSpec::eCore_arm_aarch64))
+                                    (core >= ArchSpec::eCore_arm_generic && core <= ArchSpec::eCore_arm_aarch64))
                                     wp_sp = GetTarget().GetWatchpointList().FindByAddress(wp_hit_addr);
                                 if (!wp_sp)
                                     wp_sp = GetTarget().GetWatchpointList().FindByAddress(wp_addr);