Implement bzero, memset, memmove builtins.

This subsumes Nico Weber's patch and implements bzero in terms
of llvm.memset to match llvm-gcc.

llvm-svn: 53888

3 files changed, 45 insertions, 10 deletions

diff --git a/clang/include/clang/AST/Builtins.def b/clang/include/clang/AST/Builtins.def
index f38f431d3d2..126609b04dc 100644
--- a/clang/include/clang/AST/Builtins.def
+++ b/clang/include/clang/AST/Builtins.def
@@ -117,7 +117,10 @@ BUILTIN(__builtin_va_start, "va&.", "n")
 BUILTIN(__builtin_va_end, "va&", "n")
 BUILTIN(__builtin_va_copy, "va&a", "n")
 BUILTIN(__builtin_stdarg_start, "va&a", "n")
+BUILTIN(__builtin_bzero, "vv*z", "n")
 BUILTIN(__builtin_memcpy, "v*v*vC*z", "n")
+BUILTIN(__builtin_memmove, "v*v*vC*z", "n")
+BUILTIN(__builtin_memset, "v*v*cz", "n")
 BUILTIN(__builtin_return_address, "v*Ui", "n")
 BUILTIN(__builtin_frame_address, "v*Ui", "n")
 // GCC Object size checking builtins
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 87d09a981d2..9de5a5acd4b 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -291,18 +291,39 @@ RValue CodeGenFunction::EmitBuiltinExpr(unsigned BuiltinID, const CallExpr *E) {
     // FIXME: LLVM IR Should allow alloca with an i64 size!
     Value *Size = EmitScalarExpr(E->getArg(0));
     Size = Builder.CreateIntCast(Size, llvm::Type::Int32Ty, false, "tmp");
-    return RValue::get(Builder.CreateAlloca(llvm::Type::Int8Ty, Size,
-                                            "tmp"));
+    return RValue::get(Builder.CreateAlloca(llvm::Type::Int8Ty, Size, "tmp"));
+  }
+  case Builtin::BI__builtin_bzero: {
+    Value *Address = EmitScalarExpr(E->getArg(0));
+    Builder.CreateCall4(CGM.getMemSetFn(), Address,
+                        llvm::ConstantInt::get(llvm::Type::Int8Ty, 0),
+                        EmitScalarExpr(E->getArg(1)),
+                        llvm::ConstantInt::get(llvm::Type::Int32Ty, 1));
+    return RValue::get(Address);
   }
   case Builtin::BI__builtin_memcpy: {
-    Value* MemCpyOps[4] = {
-      EmitScalarExpr(E->getArg(0)),
-      EmitScalarExpr(E->getArg(1)),
-      EmitScalarExpr(E->getArg(2)),
-      llvm::ConstantInt::get(llvm::Type::Int32Ty, 0)
-    };
-    Builder.CreateCall(CGM.getMemCpyFn(), MemCpyOps, MemCpyOps+4);
-    return RValue::get(MemCpyOps[0]);
+    Value *Address = EmitScalarExpr(E->getArg(0));
+    Builder.CreateCall4(CGM.getMemCpyFn(), Address,
+                        EmitScalarExpr(E->getArg(1)),
+                        EmitScalarExpr(E->getArg(2)),
+                        llvm::ConstantInt::get(llvm::Type::Int32Ty, 1));
+    return RValue::get(Address);
+  }
+  case Builtin::BI__builtin_memmove: {
+    Value *Address = EmitScalarExpr(E->getArg(0));
+    Builder.CreateCall4(CGM.getMemMoveFn(), Address,
+                        EmitScalarExpr(E->getArg(1)),
+                        EmitScalarExpr(E->getArg(2)),
+                        llvm::ConstantInt::get(llvm::Type::Int32Ty, 1));
+    return RValue::get(Address);
+  }
+  case Builtin::BI__builtin_memset: {
+    Value *Address = EmitScalarExpr(E->getArg(0));
+    Builder.CreateCall4(CGM.getMemSetFn(), Address,
+                        EmitScalarExpr(E->getArg(1)),
+                        EmitScalarExpr(E->getArg(2)),
+                        llvm::ConstantInt::get(llvm::Type::Int32Ty, 1));
+    return RValue::get(Address);
   }
   case Builtin::BI__builtin_return_address: {
     Value *F = CGM.getIntrinsic(Intrinsic::returnaddress, 0, 0);
diff --git a/clang/test/CodeGen/builtin-memfns.c b/clang/test/CodeGen/builtin-memfns.c
new file mode 100644
index 00000000000..d28a48c5374
--- /dev/null
+++ b/clang/test/CodeGen/builtin-memfns.c
@@ -0,0 +1,11 @@
+// RUN: clang -emit-llvm -o - %s | not grep __builtin
+
+int main(int argc, char **argv) {
+  unsigned char a = 0x11223344;
+  unsigned char b = 0x11223344;
+  __builtin_bzero(&a, sizeof(a));
+  __builtin_memset(&a, 0, sizeof(a));
+  __builtin_memcpy(&a, &b, sizeof(a));
+  __builtin_memmove(&a, &b, sizeof(a));
+  return 0;
+}