fix the encoding of the "jump on *cx" family of instructions,

rdar://8061602


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113343 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/AsmParser/X86AsmParser.cpp

@@ -615,15 +615,6 @@ X86Operand *X86ATTAsmParser::ParseMemOperand(unsigned SegReg, SMLoc MemStart) {
 bool X86ATTAsmParser::
 ParseInstruction(StringRef Name, SMLoc NameLoc,
                  SmallVectorImpl<MCParsedAsmOperand*> &Operands) {
-
-  // The "Jump if rCX Zero" form jcxz is not allowed in 64-bit mode and
-  // the form jrcxz is not allowed in 32-bit mode.
-  if (Is64Bit) {
-    // FIXME: We can do jcxz/jecxz, we just don't have the encoding right yet.
-    if (Name == "jcxz" || Name == "jecxz")
-      return Error(NameLoc, Name + " cannot be encoded in 64-bit mode");
-  }
-
   // FIXME: Hack to recognize "sal..." and "rep..." for now. We need a way to
   // represent alternative syntaxes in the .td file, without requiring
   // instruction duplication.
@@ -646,11 +637,6 @@ ParseInstruction(StringRef Name, SMLoc NameLoc,
     .Case("jz", "je")
     .Case("jnz", "jne")
     .Case("jc", "jb")
-    // FIXME: in 32-bit mode jcxz requires an AdSize prefix. In 64-bit mode
-    // jecxz requires an AdSize prefix but jecxz does not have a prefix in
-    // 32-bit mode.
-    .Case("jecxz", "jcxz")
-    .Case("jrcxz", Is64Bit ? "jcxz" : "jrcxz")
     .Case("jna", "jbe")
     .Case("jnae", "jb")
     .Case("jnb", "jae")

lib/Target/X86/X86InstrInfo.td

@@ -664,10 +664,28 @@ defm JGE : ICBr<0x7D, 0x8D, "jge\t$dst", X86_COND_GE>;
 defm JLE : ICBr<0x7E, 0x8E, "jle\t$dst", X86_COND_LE>;
 defm JG  : ICBr<0x7F, 0x8F, "jg\t$dst" , X86_COND_G>;
 
-// FIXME: What about the CX/RCX versions of this instruction?
-let Uses = [ECX], isBranch = 1, isTerminator = 1 in
-  def JCXZ8 : Ii8PCRel<0xE3, RawFrm, (outs), (ins brtarget8:$dst),
-                       "jcxz\t$dst", []>;
+// jcx/jecx/jrcx instructions.
+let isAsmParserOnly = 1, isBranch = 1, isTerminator = 1 in {
+  // These are the 32-bit versions of this instruction for the asmparser.  In
+  // 32-bit mode, the address size prefix is jcxz and the unprefixed version is
+  // jecxz.
+  let Uses = [CX] in
+    def JCXZ : Ii8PCRel<0xE3, RawFrm, (outs), (ins brtarget8:$dst),
+                        "jcxz\t$dst", []>, AdSize, Requires<[In32BitMode]>;
+  let Uses = [ECX] in
+    def JECXZ_32 : Ii8PCRel<0xE3, RawFrm, (outs), (ins brtarget8:$dst),
+                           "jecxz\t$dst", []>, Requires<[In32BitMode]>;
+
+  // J*CXZ instruction: 64-bit versions of this instruction for the asmparser.
+  // In 64-bit mode, the address size prefix is jecxz and the unprefixed version
+  // is jrcxz.
+  let Uses = [ECX] in
+    def JECXZ_64 : Ii8PCRel<0xE3, RawFrm, (outs), (ins brtarget8:$dst),
+                            "jecxz\t$dst", []>, AdSize, Requires<[In64BitMode]>;
+  let Uses = [RCX] in
+    def JRCXZ : Ii8PCRel<0xE3, RawFrm, (outs), (ins brtarget8:$dst),
+                           "jrcxz\t$dst", []>, Requires<[In64BitMode]>;
+}
 
 
 // Indirect branches

test/MC/AsmParser/X86/x86_32-new-encoder.s

@@ -423,3 +423,14 @@ retl
 // CHECK: lcalll $2, $4660
 // CHECK:   encoding: [0x9a,0x34,0x12,0x00,0x00,0x02,0x00]
 lcalll $0x2, $0x1234
+
+
+// rdar://8061602
+L1:
+  jcxz L1
+// CHECK: jcxz L1
+// CHECK:   encoding: [0x67,0xe3,A]
+  jecxz L1
+// CHECK: jecxz L1
+// CHECK:   encoding: [0xe3,A]
+

test/MC/AsmParser/X86/x86_64-new-encoder.s

@@ -157,3 +157,14 @@ btq $0x01,%rdx
 // CHECK: btq $61, -216(%rbp)
 // CHECK:   encoding: [0x48,0x0f,0xba,0xa5,0x28,0xff,0xff,0xff,0x3d]
 	btq	$61, -216(%rbp)
+
+
+// rdar://8061602
+L1:
+  jecxz L1
+// CHECK: jecxz L1
+// CHECK:   encoding: [0x67,0xe3,A]
+  jrcxz L1
+// CHECK: jrcxz L1
+// CHECK:   encoding: [0xe3,A]
+

test/MC/MachO/jcc.s

@@ -10,7 +10,7 @@
 1: nop
    jc 1f
 1: nop
-   jcxz 1f
+   jecxz 1f
 1: nop
    jecxz 1f
 1: nop