[clang] [clang codegen] Add CreateRuntimeFunction overload that takes a clang type. (PR #113506)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic created https://github.com/llvm/llvm-project/pull/113506

Correctly computing the LLVM types/attributes is complicated in general, so add a variant which does that for you.

>From 852334cad31df42463a831f9c53cc4ac4535b93c Mon Sep 17 00:00:00 2001
From: Eli Friedman <efriedma at quicinc.com>
Date: Wed, 23 Oct 2024 16:12:27 -0700
Subject: [PATCH] [clang codegen] Add CreateRuntimeFunction overload that takes
 a clang type.

Correctly computing the LLVM types/attributes is complicated in general,
so add a variant which does that for you.
---
 clang/lib/CodeGen/CGBlocks.cpp      | 14 +++----
 clang/lib/CodeGen/CodeGenModule.cpp | 61 ++++++++++++++++++++++-------
 clang/lib/CodeGen/CodeGenModule.h   |  6 +++
 3 files changed, 59 insertions(+), 22 deletions(-)

diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 41bb8d19d161eb..1661a242c80b57 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -2839,10 +2839,9 @@ llvm::FunctionCallee CodeGenModule::getBlockObjectDispose() {
   if (BlockObjectDispose)
     return BlockObjectDispose;
 
-  llvm::Type *args[] = { Int8PtrTy, Int32Ty };
-  llvm::FunctionType *fty
-    = llvm::FunctionType::get(VoidTy, args, false);
-  BlockObjectDispose = CreateRuntimeFunction(fty, "_Block_object_dispose");
+  QualType args[] = {Context.VoidPtrTy, Context.IntTy};
+  BlockObjectDispose =
+      CreateRuntimeFunction(Context.VoidTy, args, "_Block_object_dispose");
   configureBlocksRuntimeObject(
       *this, cast<llvm::Constant>(BlockObjectDispose.getCallee()));
   return BlockObjectDispose;
@@ -2852,10 +2851,9 @@ llvm::FunctionCallee CodeGenModule::getBlockObjectAssign() {
   if (BlockObjectAssign)
     return BlockObjectAssign;
 
-  llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty };
-  llvm::FunctionType *fty
-    = llvm::FunctionType::get(VoidTy, args, false);
-  BlockObjectAssign = CreateRuntimeFunction(fty, "_Block_object_assign");
+  QualType args[] = {Context.VoidPtrTy, Context.VoidPtrTy, Context.IntTy};
+  BlockObjectAssign =
+      CreateRuntimeFunction(Context.VoidTy, args, "_Block_object_assign");
   configureBlocksRuntimeObject(
       *this, cast<llvm::Constant>(BlockObjectAssign.getCallee()));
   return BlockObjectAssign;
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 2bcca5e85bdfeb..8d7f85fb445424 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -4903,6 +4903,52 @@ GetRuntimeFunctionDecl(ASTContext &C, StringRef Name) {
   return nullptr;
 }
 
+static void setWindowsItaniumDLLImport(CodeGenModule &CGM, bool Local,
+                                       llvm::Function *F, StringRef Name) {
+  // In Windows Itanium environments, try to mark runtime functions
+  // dllimport. For Mingw and MSVC, don't. We don't really know if the user
+  // will link their standard library statically or dynamically. Marking
+  // functions imported when they are not imported can cause linker errors
+  // and warnings.
+  if (!Local && CGM.getTriple().isWindowsItaniumEnvironment() &&
+      !CGM.getCodeGenOpts().LTOVisibilityPublicStd) {
+    const FunctionDecl *FD = GetRuntimeFunctionDecl(CGM.getContext(), Name);
+    if (!FD || FD->hasAttr<DLLImportAttr>()) {
+      F->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
+      F->setLinkage(llvm::GlobalValue::ExternalLinkage);
+    }
+  }
+}
+
+llvm::FunctionCallee CodeGenModule::CreateRuntimeFunction(
+    QualType ReturnTy, ArrayRef<QualType> ArgTys, StringRef Name,
+    llvm::AttributeList ExtraAttrs, bool Local, bool AssumeConvergent) {
+  if (AssumeConvergent) {
+    ExtraAttrs =
+        ExtraAttrs.addFnAttribute(VMContext, llvm::Attribute::Convergent);
+  }
+
+  QualType FTy = Context.getFunctionType(Context.VoidTy, ArgTys,
+                                         FunctionProtoType::ExtProtoInfo());
+  const CGFunctionInfo &Info = getTypes().arrangeFreeFunctionType(
+      Context.getCanonicalType(FTy).castAs<FunctionProtoType>());
+  auto *ConvTy = getTypes().GetFunctionType(Info);
+  llvm::Constant *C = GetOrCreateLLVMFunction(
+      Name, ConvTy, GlobalDecl(), /*ForVTable=*/false,
+      /*DontDefer=*/false, /*IsThunk=*/false, ExtraAttrs);
+
+  if (auto *F = dyn_cast<llvm::Function>(C)) {
+    if (F->empty()) {
+      SetLLVMFunctionAttributes(GlobalDecl(), Info, F, /*IsThunk*/ false);
+      // FIXME: Set calling-conv properly in ExtProtoInfo
+      F->setCallingConv(getRuntimeCC());
+      setWindowsItaniumDLLImport(*this, Local, F, Name);
+      setDSOLocal(F);
+    }
+  }
+  return {ConvTy, C};
+}
+
 /// CreateRuntimeFunction - Create a new runtime function with the specified
 /// type and name.
 llvm::FunctionCallee
@@ -4922,20 +4968,7 @@ CodeGenModule::CreateRuntimeFunction(llvm::FunctionType *FTy, StringRef Name,
   if (auto *F = dyn_cast<llvm::Function>(C)) {
     if (F->empty()) {
       F->setCallingConv(getRuntimeCC());
-
-      // In Windows Itanium environments, try to mark runtime functions
-      // dllimport. For Mingw and MSVC, don't. We don't really know if the user
-      // will link their standard library statically or dynamically. Marking
-      // functions imported when they are not imported can cause linker errors
-      // and warnings.
-      if (!Local && getTriple().isWindowsItaniumEnvironment() &&
-          !getCodeGenOpts().LTOVisibilityPublicStd) {
-        const FunctionDecl *FD = GetRuntimeFunctionDecl(Context, Name);
-        if (!FD || FD->hasAttr<DLLImportAttr>()) {
-          F->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
-          F->setLinkage(llvm::GlobalValue::ExternalLinkage);
-        }
-      }
+      setWindowsItaniumDLLImport(*this, Local, F, Name);
       setDSOLocal(F);
       // FIXME: We should use CodeGenModule::SetLLVMFunctionAttributes() instead
       // of trying to approximate the attributes using the LLVM function
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 1b77490e261c21..6f410539487630 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -1254,6 +1254,12 @@ class CodeGenModule : public CodeGenTypeCache {
                         llvm::AttributeList ExtraAttrs = llvm::AttributeList(),
                         bool Local = false, bool AssumeConvergent = false);
 
+  llvm::FunctionCallee
+  CreateRuntimeFunction(QualType ReturnTy, ArrayRef<QualType> ArgTys,
+                        StringRef Name,
+                        llvm::AttributeList ExtraAttrs = llvm::AttributeList(),
+                        bool Local = false, bool AssumeConvergent = false);
+
   /// Create a new runtime global variable with the specified type and name.
   llvm::Constant *CreateRuntimeVariable(llvm::Type *Ty,
                                         StringRef Name);