From: Coby Tayree <coby.tayree@intel.com>
Date: Mon, 21 Aug 2017 07:50:15 +0000 (+0000)
Subject: [X86] Allow xacquire/xrelease prefixes
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=745029aaf7eb870095e6ffdbe095e2fc34d9f5c6;p=llvm

[X86] Allow xacquire/xrelease prefixes

Allow those prefixes on assembly code
Differential Revision: https://reviews.llvm.org/D36845


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311309 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 881d35eb892..d9eeeece1d9 100644
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -2457,11 +2457,21 @@ bool X86AsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
   Operands.push_back(X86Operand::CreateToken(PatchedName, NameLoc));
 
   // Determine whether this is an instruction prefix.
-  bool isPrefix =
-    Name == "lock" || Name == "rep" ||
-    Name == "repe" || Name == "repz" ||
-    Name == "repne" || Name == "repnz" ||
-    Name == "rex64" || Name == "data16" || Name == "data32";
+  // FIXME:
+  // Enhace prefixes integrity robustness. for example, following forms
+  // are currently tolerated:
+  // repz repnz <insn>    ; GAS errors for the use of two similar prefixes
+  // lock addq %rax, %rbx ; Destination operand must be of memory type
+  // xacquire <insn>      ; xacquire must be accompanied by 'lock'
+  bool isPrefix = StringSwitch<bool>(Name)
+    .Cases("lock",
+           "rep",       "repe",
+           "repz",      "repne",
+           "repnz",     "rex64",
+           "data32",    "data16",   true)
+    .Cases("xacquire",  "xrelease", true)
+    .Cases("acquire",   "release",  isParsingIntelSyntax())
+    .Default(false);
 
   bool CurlyAsEndOfStatement = false;
   // This does the actual operand parsing.  Don't parse any more if we have a
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index 1fc174750c7..2972de2e448 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -2848,6 +2848,10 @@ def : MnemonicAlias<"smovq", "movsq", "att">;
 def : MnemonicAlias<"ud2a",  "ud2",  "att">;
 def : MnemonicAlias<"verrw", "verr", "att">;
 
+// MS recognizes 'xacquire'/'xrelease' as 'acquire'/'release'
+def : MnemonicAlias<"acquire", "xacquire", "intel">;
+def : MnemonicAlias<"release", "xrelease", "intel">;
+
 // System instruction aliases.
 def : MnemonicAlias<"iret",    "iretw",    "att">, Requires<[In16BitMode]>;
 def : MnemonicAlias<"iret",    "iretl",    "att">, Requires<[Not16BitMode]>;
diff --git a/test/MC/X86/intel-syntax-encoding.s b/test/MC/X86/intel-syntax-encoding.s
index 9907cfe6f75..e6ddc87f558 100644
--- a/test/MC/X86/intel-syntax-encoding.s
+++ b/test/MC/X86/intel-syntax-encoding.s
@@ -52,6 +52,15 @@
 // CHECK: encoding: [0x48,0x83,0xf8,0xf4]
 	cmp	rax, -12
 
+  acquire lock add [rax], rax
+// CHECK: encoding: [0xf2]
+// CHECK: encoding: [0xf0]
+// CHECK: encoding: [0x48,0x01,0x00]
+  release lock add [rax], rax
+// CHECK: encoding: [0xf3]
+// CHECK: encoding: [0xf0]
+// CHECK: encoding: [0x48,0x01,0x00]
+
 LBB0_3:
 // CHECK: encoding: [0xeb,A]
 	jmp	LBB0_3
diff --git a/test/MC/X86/x86-64.s b/test/MC/X86/x86-64.s
index 3d7ab87f5ea..1fe17831e7e 100644
--- a/test/MC/X86/x86-64.s
+++ b/test/MC/X86/x86-64.s
@@ -930,6 +930,21 @@ lock xorq %rsi, (%rdi)
 // CHECK: xorq %rsi, (%rdi)
 // CHECK: encoding: [0x48,0x31,0x37]
 
+xacquire lock addq %rax, (%rax)
+// CHECK: xacquire
+// CHECK: encoding: [0xf2]
+// CHECK: lock
+// CHECK: encoding: [0xf0]
+// CHECK: addq %rax, (%rax)
+// CHECK: encoding: [0x48,0x01,0x00]
+
+xrelease lock addq %rax, (%rax)
+// CHECK: xrelease
+// CHECK: encoding: [0xf3]
+// CHECK: lock
+// CHECK: encoding: [0xf0]
+// CHECK: addq %rax, (%rax)
+// CHECK: encoding: [0x48,0x01,0x00]
 
 // rdar://8033482
 rep movsl