[X86] Implement __readgsqword (and the rest) as builtins (PR32373)

It seems MS headers have started using __readgsqword, and since it's
used in a header that doesn't include intrin.h, we can't implement it as
an inline function anymore.

That was already the case for __readfsdword, which Saleem added support
for in r220859. This patch reuses that codegen to implement all of
__read[fg]s{byte,word,dword,qword}.

Differential Revision: https://reviews.llvm.org/D31248

llvm-svn: 298538

2 files changed, 24 insertions, 53 deletions

diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 817589064a3..463dda4213a 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -2238,16 +2238,6 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
   case Builtin::BI_InterlockedXor16:
   case Builtin::BI_InterlockedXor:
     return RValue::get(EmitMSVCBuiltinExpr(MSVCIntrin::_InterlockedXor, E));
-  case Builtin::BI__readfsdword: {
-    llvm::Type *IntTy = ConvertType(E->getType());
-    Value *IntToPtr =
-      Builder.CreateIntToPtr(EmitScalarExpr(E->getArg(0)),
-                             llvm::PointerType::get(IntTy, 257));
-    LoadInst *Load = Builder.CreateAlignedLoad(
-        IntTy, IntToPtr, getContext().getTypeAlignInChars(E->getType()));
-    Load->setVolatile(true);
-    return RValue::get(Load);
-  }
 
   case Builtin::BI__exception_code:
   case Builtin::BI_exception_code:
@@ -8005,6 +7995,30 @@ Value *CodeGenFunction::EmitX86BuiltinExpr(unsigned BuiltinID,
     CS.setAttributes(NoReturnAttr);
     return CS.getInstruction();
   }
+  case X86::BI__readfsbyte:
+  case X86::BI__readfsword:
+  case X86::BI__readfsdword:
+  case X86::BI__readfsqword: {
+    llvm::Type *IntTy = ConvertType(E->getType());
+    Value *Ptr = Builder.CreateIntToPtr(EmitScalarExpr(E->getArg(0)),
+                                        llvm::PointerType::get(IntTy, 257));
+    LoadInst *Load = Builder.CreateAlignedLoad(
+        IntTy, Ptr, getContext().getTypeAlignInChars(E->getType()));
+    Load->setVolatile(true);
+    return Load;
+  }
+  case X86::BI__readgsbyte:
+  case X86::BI__readgsword:
+  case X86::BI__readgsdword:
+  case X86::BI__readgsqword: {
+    llvm::Type *IntTy = ConvertType(E->getType());
+    Value *Ptr = Builder.CreateIntToPtr(EmitScalarExpr(E->getArg(0)),
+                                        llvm::PointerType::get(IntTy, 256));
+    LoadInst *Load = Builder.CreateAlignedLoad(
+        IntTy, Ptr, getContext().getTypeAlignInChars(E->getType()));
+    Load->setVolatile(true);
+    return Load;
+  }
   }
 }
 
diff --git a/clang/lib/Headers/intrin.h b/clang/lib/Headers/intrin.h
index af87914a9a0..16028d5c6b0 100644
--- a/clang/lib/Headers/intrin.h
+++ b/clang/lib/Headers/intrin.h
@@ -869,50 +869,7 @@ _InterlockedCompareExchange64_rel(__int64 volatile *_Destination,
   return _Comparand;
 }
 #endif
-/*----------------------------------------------------------------------------*\
-|* readfs, readgs
-|* (Pointers in address space #256 and #257 are relative to the GS and FS
-|* segment registers, respectively.)
-\*----------------------------------------------------------------------------*/
-#define __ptr_to_addr_space(__addr_space_nbr, __type, __offset)              \
-    ((volatile __type __attribute__((__address_space__(__addr_space_nbr)))*) \
-    (__offset))
 
-#ifdef __i386__
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-__readfsbyte(unsigned long __offset) {
-  return *__ptr_to_addr_space(257, unsigned char, __offset);
-}
-static __inline__ unsigned short __DEFAULT_FN_ATTRS
-__readfsword(unsigned long __offset) {
-  return *__ptr_to_addr_space(257, unsigned short, __offset);
-}
-static __inline__ unsigned __int64 __DEFAULT_FN_ATTRS
-__readfsqword(unsigned long __offset) {
-  return *__ptr_to_addr_space(257, unsigned __int64, __offset);
-}
-#endif
-#ifdef __x86_64__
-static __inline__ unsigned char __DEFAULT_FN_ATTRS
-__readgsbyte(unsigned long __offset) {
-  return *__ptr_to_addr_space(256, unsigned char, (unsigned long long)__offset);
-}
-static __inline__ unsigned short __DEFAULT_FN_ATTRS
-__readgsword(unsigned long __offset) {
-  return *__ptr_to_addr_space(256, unsigned short,
-                              (unsigned long long)__offset);
-}
-static __inline__ unsigned long __DEFAULT_FN_ATTRS
-__readgsdword(unsigned long __offset) {
-  return *__ptr_to_addr_space(256, unsigned long, (unsigned long long)__offset);
-}
-static __inline__ unsigned __int64 __DEFAULT_FN_ATTRS
-__readgsqword(unsigned long __offset) {
-  return *__ptr_to_addr_space(256, unsigned __int64,
-                              (unsigned long long)__offset);
-}
-#endif
-#undef __ptr_to_addr_space
 /*----------------------------------------------------------------------------*\
 |* movs, stos
 \*----------------------------------------------------------------------------*/