[X86][APX] Distinguish REX2 PUSH/POP from PPX (#163526)

Author: phoebewang

llvm/include/llvm/Support/X86DisassemblerDecoderCommon.h

@@ -121,6 +121,7 @@ enum attributeBits {
              "The Dynamic Duo!  Prefer over all else because this changes "    \
              "most operands' meaning")                                         \
   ENUM_ENTRY(IC_64BIT_REX2, 2, "requires a REX2 prefix")                       \
+  ENUM_ENTRY(IC_64BIT_REX2_REXW, 3, "requires a REX2 and the W prefix")        \
   ENUM_ENTRY(IC_VEX, 1, "requires a VEX prefix")                               \
   ENUM_ENTRY(IC_VEX_XS, 2, "requires VEX and the XS prefix")                   \
   ENUM_ENTRY(IC_VEX_XD, 2, "requires VEX and the XD prefix")                   \

llvm/test/MC/Disassembler/X86/apx/pushp-popp.txt

@@ -17,6 +17,10 @@
 # INTEL: pushp	r16
 0xd5,0x18,0x50
 
+# ATT:   pushq	%r16
+# INTEL: push	r16
+0xd5,0x10,0x50
+
 # ATT:   popp	%rax
 # INTEL: popp	rax
 0xd5,0x08,0x58
@@ -32,3 +36,7 @@
 # ATT:   popp	%r16
 # INTEL: popp	r16
 0xd5,0x18,0x58
+
+# ATT:   popq	%r16
+# INTEL: pop	r16
+0xd5,0x10,0x58

llvm/test/MC/X86/apx/pushp-popp-att.s

@@ -1,7 +1,7 @@
 # RUN: llvm-mc -triple x86_64 -show-encoding %s | FileCheck %s
 # RUN: not llvm-mc -triple i386 -show-encoding %s 2>&1 | FileCheck %s --check-prefix=ERROR
 
-# ERROR-COUNT-8: error:
+# ERROR-COUNT-10: error:
 # ERROR-NOT: error:
 
 # CHECK: pushp	%rax
@@ -16,6 +16,9 @@
 # CHECK: pushp	%r16
 # CHECK: encoding: [0xd5,0x18,0x50]
          pushp	%r16
+# CHECK: pushq	%r16
+# CHECK: encoding: [0xd5,0x10,0x50]
+         pushq	%r16
 
 # CHECK: popp	%rax
 # CHECK: encoding: [0xd5,0x08,0x58]
@@ -29,3 +32,6 @@
 # CHECK: popp	%r16
 # CHECK: encoding: [0xd5,0x18,0x58]
          popp	%r16
+# CHECK: popq	%r16
+# CHECK: encoding: [0xd5,0x10,0x58]
+         popq	%r16

llvm/utils/TableGen/X86DisassemblerTables.cpp

@@ -99,6 +99,7 @@ static inline bool inheritsFrom(InstructionContext child,
             (noPrefix && inheritsFrom(child, IC_XS, noPrefix)));
   case IC_64BIT:
     return (inheritsFrom(child, IC_64BIT_REXW) ||
+            inheritsFrom(child, IC_64BIT_REX2) ||
             (noPrefix && inheritsFrom(child, IC_64BIT_OPSIZE, noPrefix)) ||
             (!AdSize64 && inheritsFrom(child, IC_64BIT_ADSIZE)) ||
             (noPrefix && inheritsFrom(child, IC_64BIT_XD, noPrefix)) ||
@@ -151,8 +152,10 @@ static inline bool inheritsFrom(InstructionContext child,
   case IC_64BIT_REXW_XS:
   case IC_64BIT_REXW_OPSIZE:
   case IC_64BIT_REXW_ADSIZE:
-  case IC_64BIT_REX2:
+  case IC_64BIT_REX2_REXW:
     return false;
+  case IC_64BIT_REX2:
+    return inheritsFrom(child, IC_64BIT_REX2_REXW);
   case IC_VEX:
     return (VEX_LIG && WIG && inheritsFrom(child, IC_VEX_L_W)) ||
            (WIG && inheritsFrom(child, IC_VEX_W)) ||
@@ -980,9 +983,11 @@ void DisassemblerTables::emitContextTable(raw_ostream &o, unsigned &i) const {
         if ((index & ATTR_EVEXB) && (index & ATTR_EVEXU))
           o << "_U";
       }
-    } else if ((index & ATTR_64BIT) && (index & ATTR_REX2))
+    } else if ((index & ATTR_64BIT) && (index & ATTR_REX2)) {
       o << "IC_64BIT_REX2";
-    else if ((index & ATTR_64BIT) && (index & ATTR_REXW) && (index & ATTR_XS))
+      if (index & ATTR_REXW)
+        o << "_REXW";
+    } else if ((index & ATTR_64BIT) && (index & ATTR_REXW) && (index & ATTR_XS))
       o << "IC_64BIT_REXW_XS";
     else if ((index & ATTR_64BIT) && (index & ATTR_REXW) && (index & ATTR_XD))
       o << "IC_64BIT_REXW_XD";

llvm/utils/TableGen/X86RecognizableInstr.cpp

@@ -365,6 +365,8 @@ InstructionContext RecognizableInstr::insnContext() const {
       insnContext = IC_64BIT_XD;
     else if (OpPrefix == X86Local::XS)
       insnContext = IC_64BIT_XS;
+    else if (HasREX_W && ExplicitREX2Prefix)
+      insnContext = IC_64BIT_REX2_REXW;
     else if (ExplicitREX2Prefix)
       insnContext = IC_64BIT_REX2;
     else if (HasREX_W)