1//===- DeclareRuntimeLibcalls.cpp -----------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Insert declarations for all runtime library calls known for the target.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/Transforms/Utils/DeclareRuntimeLibcalls.h"
14#include "llvm/Analysis/RuntimeLibcallInfo.h"
15#include "llvm/IR/Module.h"
16#include "llvm/IR/RuntimeLibcalls.h"
17
18using namespace llvm;
19
20static void mergeAttributes(LLVMContext &Ctx, const Module &M,
21 const DataLayout &DL, const Triple &TT,
22 Function *Func, FunctionType *FuncTy,
23 AttributeList FuncAttrs) {
24 AttributeList OldAttrs = Func->getAttributes();
25 AttributeList NewAttrs = OldAttrs;
26
27 {
28 AttrBuilder OldBuilder(Ctx, OldAttrs.getFnAttrs());
29 AttrBuilder NewBuilder(Ctx, FuncAttrs.getFnAttrs());
30 OldBuilder.merge(B: NewBuilder);
31 NewAttrs = NewAttrs.addFnAttributes(C&: Ctx, B: OldBuilder);
32 }
33
34 {
35 AttrBuilder OldBuilder(Ctx, OldAttrs.getRetAttrs());
36 AttrBuilder NewBuilder(Ctx, FuncAttrs.getRetAttrs());
37 OldBuilder.merge(B: NewBuilder);
38 NewAttrs = NewAttrs.addRetAttributes(C&: Ctx, B: OldBuilder);
39 }
40
41 for (unsigned I = 0, E = FuncTy->getNumParams(); I != E; ++I) {
42 AttrBuilder OldBuilder(Ctx, OldAttrs.getParamAttrs(ArgNo: I));
43 AttrBuilder NewBuilder(Ctx, FuncAttrs.getParamAttrs(ArgNo: I));
44 OldBuilder.merge(B: NewBuilder);
45 NewAttrs = NewAttrs.addParamAttributes(C&: Ctx, ArgNo: I, B: OldBuilder);
46 }
47
48 Func->setAttributes(NewAttrs);
49}
50
51PreservedAnalyses DeclareRuntimeLibcallsPass::run(Module &M,
52 ModuleAnalysisManager &MAM) {
53 const RTLIB::RuntimeLibcallsInfo &RTLCI =
54 MAM.getResult<RuntimeLibraryAnalysis>(IR&: M);
55
56 LLVMContext &Ctx = M.getContext();
57 const DataLayout &DL = M.getDataLayout();
58 const Triple &TT = M.getTargetTriple();
59
60 for (RTLIB::LibcallImpl Impl : RTLIB::libcall_impls()) {
61 if (!RTLCI.isAvailable(Impl))
62 continue;
63
64 auto [FuncTy, FuncAttrs] = RTLCI.getFunctionTy(Ctx, TT, DL, LibcallImpl: Impl);
65
66 // TODO: Declare with correct type, calling convention, and attributes.
67 if (!FuncTy)
68 FuncTy = FunctionType::get(Result: Type::getVoidTy(C&: Ctx), Params: {}, /*IsVarArgs=*/isVarArg: true);
69
70 StringRef FuncName = RTLCI.getLibcallImplName(CallImpl: Impl);
71
72 Function *Func =
73 cast<Function>(Val: M.getOrInsertFunction(Name: FuncName, T: FuncTy).getCallee());
74 if (Func->getFunctionType() == FuncTy) {
75 mergeAttributes(Ctx, M, DL, TT, Func, FuncTy, FuncAttrs);
76 Func->setCallingConv(RTLCI.getLibcallImplCallingConv(Call: Impl));
77 }
78 }
79
80 return PreservedAnalyses::none();
81}
82