Add support in the disassembler for ignoring the L-bit on certain VEX instructions. Mark instructions that have this behavior. Fixes PR10676.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141065 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 25 insertions, 20 deletions

diff --git a/utils/TableGen/X86DisassemblerTables.cpp b/utils/TableGen/X86DisassemblerTables.cpp
index ac867dc..218a1a2 100644
--- a/utils/TableGen/X86DisassemblerTables.cpp
+++ b/utils/TableGen/X86DisassemblerTables.cpp
@@ -32,7 +32,8 @@ using namespace X86Disassembler;
 /// @param parent - The class that may be the superset
 /// @return       - True if child is a subset of parent, false otherwise.
 static inline bool inheritsFrom(InstructionContext child,
-                                InstructionContext parent) {
+                                InstructionContext parent,
+                                bool VEX_LIG = false) {
   if (child == parent)
     return true;
   
@@ -68,33 +69,29 @@ static inline bool inheritsFrom(InstructionContext child,
   case IC_64BIT_XD_OPSIZE:
     return false;
   case IC_64BIT_REXW_XD:
-    return false;
   case IC_64BIT_REXW_XS:
-    return false;
   case IC_64BIT_REXW_OPSIZE:
     return false;
   case IC_VEX:
-    return inheritsFrom(child, IC_VEX_W);
+    return inheritsFrom(child, IC_VEX_W) ||
+           (VEX_LIG && inheritsFrom(child, IC_VEX_L));
   case IC_VEX_XS:
-    return inheritsFrom(child, IC_VEX_W_XS);
+    return inheritsFrom(child, IC_VEX_W_XS) ||
+           (VEX_LIG && inheritsFrom(child, IC_VEX_L_XS));
   case IC_VEX_XD:
-    return inheritsFrom(child, IC_VEX_W_XD);
+    return inheritsFrom(child, IC_VEX_W_XD) ||
+           (VEX_LIG && inheritsFrom(child, IC_VEX_L_XD));
   case IC_VEX_OPSIZE:
-    return inheritsFrom(child, IC_VEX_W_OPSIZE);
+    return inheritsFrom(child, IC_VEX_W_OPSIZE) ||
+           (VEX_LIG && inheritsFrom(child, IC_VEX_L_OPSIZE));
   case IC_VEX_W:
-    return false;
   case IC_VEX_W_XS:
-    return false;
   case IC_VEX_W_XD:
-    return false;
   case IC_VEX_W_OPSIZE:
     return false;
   case IC_VEX_L:
-    return false;
   case IC_VEX_L_XS:
-    return false;
   case IC_VEX_L_XD:
-    return false;
   case IC_VEX_L_OPSIZE:
     return false;
   default:
@@ -651,7 +648,8 @@ void DisassemblerTables::setTableFields(OpcodeType          type,
                                         uint8_t             opcode,
                                         const ModRMFilter   &filter,
                                         InstrUID            uid,
-                                        bool                is32bit) {
+                                        bool                is32bit,
+                                        bool                ignoresVEX_L) {
   unsigned index;
   
   ContextDecision &decision = *Tables[type];
@@ -661,7 +659,7 @@ void DisassemblerTables::setTableFields(OpcodeType          type,
       continue;
 
     if (inheritsFrom((InstructionContext)index, 
-                     InstructionSpecifiers[uid].insnContext))
+                     InstructionSpecifiers[uid].insnContext, ignoresVEX_L))
       setTableFields(decision.opcodeDecisions[index].modRMDecisions[opcode], 
                      filter,
                      uid,
diff --git a/utils/TableGen/X86DisassemblerTables.h b/utils/TableGen/X86DisassemblerTables.h
index ae126be..e148cd2 100644
--- a/utils/TableGen/X86DisassemblerTables.h
+++ b/utils/TableGen/X86DisassemblerTables.h
@@ -261,12 +261,14 @@ public:
   ///                       correspond to the desired instruction.
   /// @param uid          - The unique ID of the instruction.
   /// @param is32bit      - Instructon is only 32-bit
+  /// @param ignoresVEX_L - Instruction ignores VEX.L
   void setTableFields(OpcodeType type,
                       InstructionContext insnContext,
                       uint8_t opcode,
                       const ModRMFilter &filter,
                       InstrUID uid,
-                      bool is32bit);  
+                      bool is32bit,
+                      bool ignoresVEX_L);  
   
   /// specForUID - Returns the instruction specifier for a given unique
   ///   instruction ID.  Used when resolving collisions.
diff --git a/utils/TableGen/X86RecognizableInstr.cpp b/utils/TableGen/X86RecognizableInstr.cpp
index 787e4df..f958966 100644
--- a/utils/TableGen/X86RecognizableInstr.cpp
+++ b/utils/TableGen/X86RecognizableInstr.cpp
@@ -217,6 +217,7 @@ RecognizableInstr::RecognizableInstr(DisassemblerTables &tables,
   HasVEXPrefix     = Rec->getValueAsBit("hasVEXPrefix");
   HasVEX_4VPrefix  = Rec->getValueAsBit("hasVEX_4VPrefix");
   HasVEX_WPrefix   = Rec->getValueAsBit("hasVEX_WPrefix");
+  IgnoresVEX_L     = Rec->getValueAsBit("ignoresVEX_L");
   HasLockPrefix    = Rec->getValueAsBit("hasLockPrefix");
   IsCodeGenOnly    = Rec->getValueAsBit("isCodeGenOnly");
   
@@ -284,7 +285,9 @@ InstructionContext RecognizableInstr::insnContext() const {
   InstructionContext insnContext;
 
   if (HasVEX_4VPrefix || HasVEXPrefix) {
-    if (HasOpSizePrefix && HasVEX_LPrefix)
+    if (HasVEX_LPrefix && HasVEX_WPrefix)
+      llvm_unreachable("Don't support VEX.L and VEX.W together");
+    else if (HasOpSizePrefix && HasVEX_LPrefix)
       insnContext = IC_VEX_L_OPSIZE;
     else if (HasOpSizePrefix && HasVEX_WPrefix)
       insnContext = IC_VEX_W_OPSIZE;
@@ -957,7 +960,7 @@ void RecognizableInstr::emitDecodePath(DisassemblerTables &tables) const {
                               insnContext(), 
                               currentOpcode, 
                               *filter, 
-                              UID, Is32Bit);
+                              UID, Is32Bit, IgnoresVEX_L);
     
       Spec->modifierType = MODIFIER_OPCODE;
       Spec->modifierBase = opcodeToSet;
@@ -967,14 +970,14 @@ void RecognizableInstr::emitDecodePath(DisassemblerTables &tables) const {
                             insnContext(), 
                             opcodeToSet, 
                             *filter, 
-                            UID, Is32Bit);
+                            UID, Is32Bit, IgnoresVEX_L);
     }
   } else {
     tables.setTableFields(opcodeType,
                           insnContext(),
                           opcodeToSet,
                           *filter,
-                          UID, Is32Bit);
+                          UID, Is32Bit, IgnoresVEX_L);
     
     Spec->modifierType = MODIFIER_NONE;
     Spec->modifierBase = opcodeToSet;
diff --git a/utils/TableGen/X86RecognizableInstr.h b/utils/TableGen/X86RecognizableInstr.h
index 0b600df..4441597 100644
--- a/utils/TableGen/X86RecognizableInstr.h
+++ b/utils/TableGen/X86RecognizableInstr.h
@@ -60,6 +60,8 @@ private:
   bool HasVEX_WPrefix;
   /// Inferred from the operands; indicates whether the L bit in the VEX prefix is set
   bool HasVEX_LPrefix;
+  // The ignoreVEX_L field from the record
+  bool IgnoresVEX_L;
   /// The hasLockPrefix field from the record
   bool HasLockPrefix;
   /// The isCodeGenOnly filed from the record