[NFC][clang] Split clang/lib/CodeGen/CGBuiltin.cpp into target-specific files (#132252)

clang/lib/CodeGen/CGBuiltin.cpp is over 1MB long (>23k LoC), and can
take minutes to recompile (depending on compiler and host system) when
modified, and 5 seconds for clangd to update for every edit. Splitting
this file was discussed in this thread:

   https://discourse.llvm.org/t/splitting-clang-s-cgbuiltin-cpp-over-23k-lines-long-takes-1min-to-compile/

and the idea has received a number of +1 votes, hence this change.

Author: jthackray

clang/lib/CodeGen/CGBuiltin.cpp

@@ -0,0 +1,105 @@
+//===------ CGBuiltin.h - Emit LLVM Code for builtins ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_CODEGEN_CGBUILTIN_H
+#define LLVM_CLANG_LIB_CODEGEN_CGBUILTIN_H
+
+#include "CodeGenFunction.h"
+
+// Many of MSVC builtins are on x64, ARM and AArch64; to avoid repeating code,
+// we handle them here.
+enum class clang::CodeGen::CodeGenFunction::MSVCIntrin {
+  _BitScanForward,
+  _BitScanReverse,
+  _InterlockedAnd,
+  _InterlockedCompareExchange,
+  _InterlockedDecrement,
+  _InterlockedExchange,
+  _InterlockedExchangeAdd,
+  _InterlockedExchangeSub,
+  _InterlockedIncrement,
+  _InterlockedOr,
+  _InterlockedXor,
+  _InterlockedExchangeAdd_acq,
+  _InterlockedExchangeAdd_rel,
+  _InterlockedExchangeAdd_nf,
+  _InterlockedExchange_acq,
+  _InterlockedExchange_rel,
+  _InterlockedExchange_nf,
+  _InterlockedCompareExchange_acq,
+  _InterlockedCompareExchange_rel,
+  _InterlockedCompareExchange_nf,
+  _InterlockedCompareExchange128,
+  _InterlockedCompareExchange128_acq,
+  _InterlockedCompareExchange128_rel,
+  _InterlockedCompareExchange128_nf,
+  _InterlockedOr_acq,
+  _InterlockedOr_rel,
+  _InterlockedOr_nf,
+  _InterlockedXor_acq,
+  _InterlockedXor_rel,
+  _InterlockedXor_nf,
+  _InterlockedAnd_acq,
+  _InterlockedAnd_rel,
+  _InterlockedAnd_nf,
+  _InterlockedIncrement_acq,
+  _InterlockedIncrement_rel,
+  _InterlockedIncrement_nf,
+  _InterlockedDecrement_acq,
+  _InterlockedDecrement_rel,
+  _InterlockedDecrement_nf,
+  __fastfail,
+};
+
+// Emit a simple intrinsic that has N scalar arguments and a return type
+// matching the argument type. It is assumed that only the first argument is
+// overloaded.
+template <unsigned N>
+llvm::Value *emitBuiltinWithOneOverloadedType(clang::CodeGen::CodeGenFunction &CGF,
+                                              const clang::CallExpr *E,
+                                              unsigned IntrinsicID,
+                                              llvm::StringRef Name = "") {
+  static_assert(N, "expect non-empty argument");
+  clang::SmallVector<llvm::Value *, N> Args;
+  for (unsigned I = 0; I < N; ++I)
+    Args.push_back(CGF.EmitScalarExpr(E->getArg(I)));
+  llvm::Function *F = CGF.CGM.getIntrinsic(IntrinsicID, Args[0]->getType());
+  return CGF.Builder.CreateCall(F, Args, Name);
+}
+
+llvm::Value *emitUnaryMaybeConstrainedFPBuiltin(clang::CodeGen::CodeGenFunction &CGF,
+                                                const clang::CallExpr *E,
+                                                unsigned IntrinsicID,
+                                                unsigned ConstrainedIntrinsicID);
+
+llvm::Value *EmitToInt(clang::CodeGen::CodeGenFunction &CGF, llvm::Value *V,
+                       clang::QualType T, llvm::IntegerType *IntType);
+
+llvm::Value *EmitFromInt(clang::CodeGen::CodeGenFunction &CGF, llvm::Value *V,
+                         clang::QualType T, llvm::Type *ResultType);
+
+clang::CodeGen::Address CheckAtomicAlignment(clang::CodeGen::CodeGenFunction &CGF,
+                                             const clang::CallExpr *E);
+
+llvm::Value *MakeBinaryAtomicValue(clang::CodeGen::CodeGenFunction &CGF,
+                                   llvm::AtomicRMWInst::BinOp Kind,
+                                   const clang::CallExpr *E,
+                                   llvm::AtomicOrdering Ordering =
+                                      llvm::AtomicOrdering::SequentiallyConsistent);
+
+llvm::Value *EmitOverflowIntrinsic(clang::CodeGen::CodeGenFunction &CGF,
+                                   const llvm::Intrinsic::ID IntrinsicID,
+                                   llvm::Value *X,
+                                   llvm::Value *Y,
+                                   llvm::Value *&Carry);
+
+llvm::Value *MakeAtomicCmpXchgValue(clang::CodeGen::CodeGenFunction &CGF,
+                                    const clang::CallExpr *E,
+                                    bool ReturnBool);
+
+#endif

clang/lib/CodeGen/CGBuiltin.h

@@ -115,6 +115,16 @@ add_clang_library(clangCodeGen
   PatternInit.cpp
   SanitizerMetadata.cpp
   SwiftCallingConv.cpp
+  TargetBuiltins/ARM.cpp
+  TargetBuiltins/AMDGPU.cpp
+  TargetBuiltins/Hexagon.cpp
+  TargetBuiltins/NVPTX.cpp
+  TargetBuiltins/PPC.cpp
+  TargetBuiltins/RISCV.cpp
+  TargetBuiltins/SPIR.cpp
+  TargetBuiltins/SystemZ.cpp
+  TargetBuiltins/WebAssembly.cpp
+  TargetBuiltins/X86.cpp
   TargetInfo.cpp
   Targets/AArch64.cpp
   Targets/AMDGPU.cpp