Update qHostInfo/LC_NOTE so multiple address bits can be specified

On AArch64 systems, we may have different page table setups for
low memory and high memory, and therefore a different number of
bits used for addressing depending on which half of memory the
address is in.

This patch extends the qHostInfo and LC_NOTE "addrable bits" so
that it can specify the number of addressing bits in high memory
and in low memory separately.  It builds on the patch I added in
https://reviews.llvm.org/D151292 where Process tracks the separate
address masks, and there is a user setting to set them manually.

Differential Revision: https://reviews.llvm.org/D157667
rdar://113225907

1 files changed, 19 insertions, 3 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index c650312..f836f08 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -1265,7 +1265,15 @@ bool GDBRemoteCommunicationClient::GetHostInfo(bool force) {
             if (!value.getAsInteger(0, pointer_byte_size))
               ++num_keys_decoded;
           } else if (name.equals("addressing_bits")) {
-            if (!value.getAsInteger(0, m_addressing_bits))
+            if (!value.getAsInteger(0, m_low_mem_addressing_bits)) {
+              m_high_mem_addressing_bits = m_low_mem_addressing_bits;
+              ++num_keys_decoded;
+            }
+          } else if (name.equals("high_mem_addressing_bits")) {
+            if (!value.getAsInteger(0, m_high_mem_addressing_bits))
+              ++num_keys_decoded;
+          } else if (name.equals("low_mem_addressing_bits")) {
+            if (!value.getAsInteger(0, m_low_mem_addressing_bits))
               ++num_keys_decoded;
           } else if (name.equals("os_version") ||
                      name.equals("version")) // Older debugserver binaries used
@@ -1407,11 +1415,19 @@ GDBRemoteCommunicationClient::GetHostArchitecture() {
   return m_host_arch;
 }
 
-uint32_t GDBRemoteCommunicationClient::GetAddressingBits() {
+bool GDBRemoteCommunicationClient::GetAddressableBits(
+    lldb_private::AddressableBits &addressable_bits) {
+  addressable_bits.Clear();
   if (m_qHostInfo_is_valid == eLazyBoolCalculate)
     GetHostInfo();
-  return m_addressing_bits;
+  if (m_low_mem_addressing_bits != 0 || m_high_mem_addressing_bits != 0) {
+    addressable_bits.SetAddressableBits(m_low_mem_addressing_bits,
+                                        m_high_mem_addressing_bits);
+    return true;
+  }
+  return false;
 }
+
 seconds GDBRemoteCommunicationClient::GetHostDefaultPacketTimeout() {
   if (m_qHostInfo_is_valid == eLazyBoolCalculate)
     GetHostInfo();