[lldb] [Process] Introduce common helpers to split/recombine YMM data

Introduce two common helpers to take care of splitting and recombining
YMM registers to/from XSAVE-like data.  Since FreeBSD, Linux and NetBSD
all use XSAVE-like data structures but with potentially different field
layouts, the function takes two pointers -- to XMM register and to YMM
high bits, and copies the data from/to YMMReg type.

While at it, remove support for big endian.  To mine and Pavel Labath's
combined knowledge, there is no such thing on x86.  Furthermore,
assuming that the YMM register data would be swapped for big endian
seems to be a weird assumption.

Differential Revision: https://reviews.llvm.org/D63610

llvm-svn: 364042

2 files changed, 24 insertions, 28 deletions

diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextPOSIX_x86.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextPOSIX_x86.cpp
index 856ce9448db..4d5991f08f1 100644
--- a/lldb/source/Plugins/Process/Utility/RegisterContextPOSIX_x86.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextPOSIX_x86.cpp
@@ -474,22 +474,13 @@ bool RegisterContextPOSIX_x86::CopyYMMtoXSTATE(uint32_t reg,
     return false;
 
   if (byte_order == eByteOrderLittle) {
-    ::memcpy(m_fpr.fxsave.xmm[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes, sizeof(XMMReg));
-    ::memcpy(m_fpr.xsave.ymmh[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes + sizeof(XMMReg),
-             sizeof(YMMHReg));
+    uint32_t reg_no = reg - m_reg_info.first_ymm;
+    YMMToXState(m_ymm_set.ymm[reg_no],
+        m_fpr.fxsave.xmm[reg_no].bytes,
+        m_fpr.xsave.ymmh[reg_no].bytes);
     return true;
   }
 
-  if (byte_order == eByteOrderBig) {
-    ::memcpy(m_fpr.fxsave.xmm[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes + sizeof(XMMReg),
-             sizeof(XMMReg));
-    ::memcpy(m_fpr.xsave.ymmh[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes, sizeof(YMMHReg));
-    return true;
-  }
   return false; // unsupported or invalid byte order
 }
 
@@ -500,24 +491,13 @@ bool RegisterContextPOSIX_x86::CopyXSTATEtoYMM(uint32_t reg,
     return false;
 
   if (byte_order == eByteOrderLittle) {
-    ::memcpy(m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes,
-             m_fpr.fxsave.xmm[reg - m_reg_info.first_ymm].bytes,
-             sizeof(XMMReg));
-    ::memcpy(m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes + sizeof(XMMReg),
-             m_fpr.xsave.ymmh[reg - m_reg_info.first_ymm].bytes,
-             sizeof(YMMHReg));
+    uint32_t reg_no = reg - m_reg_info.first_ymm;
+    m_ymm_set.ymm[reg_no] = XStateToYMM(
+        m_fpr.fxsave.xmm[reg_no].bytes,
+        m_fpr.xsave.ymmh[reg_no].bytes);
     return true;
   }
 
-  if (byte_order == eByteOrderBig) {
-    ::memcpy(m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes + sizeof(XMMReg),
-             m_fpr.fxsave.xmm[reg - m_reg_info.first_ymm].bytes,
-             sizeof(XMMReg));
-    ::memcpy(m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes,
-             m_fpr.xsave.ymmh[reg - m_reg_info.first_ymm].bytes,
-             sizeof(YMMHReg));
-    return true;
-  }
   return false; // unsupported or invalid byte order
 }
 
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContext_x86.h b/lldb/source/Plugins/Process/Utility/RegisterContext_x86.h
index c3b1caba73d..2b79f778aa5 100644
--- a/lldb/source/Plugins/Process/Utility/RegisterContext_x86.h
+++ b/lldb/source/Plugins/Process/Utility/RegisterContext_x86.h
@@ -353,6 +353,22 @@ union FPR {
 
 LLVM_ENABLE_BITMASK_ENUMS_IN_NAMESPACE();
 
+// Convenience function to combine YMM register data from XSAVE-style input.
+inline YMMReg XStateToYMM(const void* xmm_bytes, const void* ymmh_bytes) {
+  YMMReg ret;
+
+  ::memcpy(ret.bytes, xmm_bytes, sizeof(XMMReg));
+  ::memcpy(ret.bytes + sizeof(XMMReg), ymmh_bytes, sizeof(YMMHReg));
+
+  return ret;
+}
+
+// Convenience function to copy YMM register data into XSAVE-style output.
+inline void YMMToXState(const YMMReg& input, void* xmm_bytes, void* ymmh_bytes) {
+  ::memcpy(xmm_bytes, input.bytes, sizeof(XMMReg));
+  ::memcpy(ymmh_bytes, input.bytes + sizeof(XMMReg), sizeof(YMMHReg));
+}
+
 } // namespace lldb_private
 
 #endif