[llvm] eb05457 - [X86] Add function isPrefix()

[Shengchen Kan via llvm-commits]

Author: Shengchen Kan
Date: 2020-01-30T14:11:50+08:00
New Revision: eb054577e9dd18dc99cc757307c1218b8e321a43

URL: https://github.com/llvm/llvm-project/commit/eb054577e9dd18dc99cc757307c1218b8e321a43
DIFF: https://github.com/llvm/llvm-project/commit/eb054577e9dd18dc99cc757307c1218b8e321a43.diff

LOG: [X86] Add function isPrefix()

Currently some prefixes are emitted as instructions, to distinguish them
from real instruction, fuction isPrefix() is added. The kinds of prefix
are consistent with X86GenInstrInfo.inc.

Differential Revision: https://reviews.llvm.org/D73013

Added: 
    

Modified: 
    llvm/lib/Target/X86/MCTargetDesc/X86BaseInfo.h

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/MCTargetDesc/X86BaseInfo.h b/llvm/lib/Target/X86/MCTargetDesc/X86BaseInfo.h
index eb94237180df..a1f73dd287d9 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86BaseInfo.h
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86BaseInfo.h
@@ -346,6 +346,33 @@ namespace X86 {
     llvm_unreachable("unknown fusion type");
   }
 
+  /// \returns true if the instruction with given opcode is a prefix.
+  inline bool isPrefix(unsigned Opcode) {
+    switch (Opcode) {
+    default:
+      return false;
+      // segment override prefix
+    case X86::CS_PREFIX:
+    case X86::DS_PREFIX:
+    case X86::ES_PREFIX:
+    case X86::FS_PREFIX:
+    case X86::GS_PREFIX:
+    case X86::SS_PREFIX:
+      // operand-size override prefix
+    case X86::DATA16_PREFIX:
+      // lock and repeat prefix
+    case X86::LOCK_PREFIX:
+    case X86::REPNE_PREFIX:
+    case X86::REP_PREFIX:
+      // rex64 prefix
+    case X86::REX64_PREFIX:
+      // acquire and release prefix
+    case X86::XACQUIRE_PREFIX:
+    case X86::XRELEASE_PREFIX:
+      return true;
+    }
+  }
+
   /// Defines the possible values of the branch boundary alignment mask.
   enum AlignBranchBoundaryKind : uint8_t {
     AlignBranchNone = 0,