Fix function pointers/delegates on Harvard architectures

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Supports LLVM 11.0 - 15.0.
 
 #### Bug fixes
+- Fix function pointers/delegates on Harvard architectures (e.g., AVR). (#4432, #4465)
 
 # LDC 1.33.0 (2023-07-23)
 

gen/declarations.cpp

@@ -419,17 +419,16 @@ class CodegenVisitor : public Visitor {
         std::string arg = ("/DEFAULTLIB:\"" + name + "\"").str();
         gIR->addLinkerOption(llvm::StringRef(arg));
       } else {
-        bool isStaticLib = name.endswith(".a");
+        const bool isStaticLib = name.endswith(".a");
+        const size_t nameLen = name.size();
 
-        size_t const nameLen = name.size();
-        size_t const n = nameLen + 3;
         char *arg = nullptr;
-
-        if (isStaticLib == false) {
+        if (!isStaticLib) { // name => -lname
+          const size_t n = nameLen + 3;
           arg = static_cast<char *>(mem.xmalloc(n));
           arg[0] = '-';
           arg[1] = 'l';
-          memcpy(arg + 2, name.data(), name.size());
+          memcpy(arg + 2, name.data(), nameLen);
           arg[n - 1] = 0;
         } else {
           arg = static_cast<char *>((mem.xmalloc(nameLen + 1)));

gen/tocall.cpp

@@ -819,7 +819,7 @@ class ImplicitArgumentsBuilder {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-static LLValue *DtoCallableValue(llvm::FunctionType * ft,DValue *fn) {
+static LLValue *DtoCallableValue(DValue *fn) {
   Type *type = fn->type->toBasetype();
   if (type->ty == TY::Tfunction) {
     return DtoRVal(fn);
@@ -829,7 +829,7 @@ static LLValue *DtoCallableValue(llvm::FunctionType * ft,DValue *fn) {
       LLValue *dg = DtoLVal(fn);
       llvm::StructType *st = isaStruct(DtoType(fn->type));
       LLValue *funcptr = DtoGEP(st, dg, 0, 1);
-      return DtoLoad(ft->getPointerTo(), funcptr, ".funcptr");
+      return DtoLoad(st->getElementType(1), funcptr, ".funcptr");
     }
     LLValue *dg = DtoRVal(fn);
     assert(isaStruct(dg));
@@ -862,7 +862,7 @@ DValue *DtoCallFunction(const Loc &loc, Type *resulttype, DValue *fnval,
   }
 
   // get callee llvm value
-  LLValue *callable = DtoCallableValue(irFty.funcType, fnval);
+  LLValue *callable = DtoCallableValue(fnval);
   LLFunctionType *callableTy = irFty.funcType;
   if (dfnval && dfnval->func->isCsymbol()) {
     // See note in DtoDeclareFunction about K&R foward declared (void) functions

ir/irtype.cpp

@@ -118,10 +118,14 @@ IrTypePointer *IrTypePointer::get(Type *dt) {
   assert(!ctype);
 
   LLType *elemType;
+  unsigned addressSpace = 0;
   if (dt->ty == TY::Tnull) {
     elemType = llvm::Type::getInt8Ty(getGlobalContext());
   } else {
     elemType = DtoMemType(dt->nextOf());
+    if (dt->nextOf()->ty == TY::Tfunction) {
+      addressSpace = gDataLayout->getProgramAddressSpace();
+    }
 
     // DtoType could have already created the same type, e.g. for
     // dt == Node* in struct Node { Node* n; }.
@@ -130,7 +134,8 @@ IrTypePointer *IrTypePointer::get(Type *dt) {
     }
   }
 
-  auto t = new IrTypePointer(dt, llvm::PointerType::get(elemType, 0));
+  auto t =
+      new IrTypePointer(dt, llvm::PointerType::get(elemType, addressSpace));
   ctype = t;
   return t;
 }

ir/irtypefunction.cpp

@@ -53,7 +53,8 @@ IrTypeDelegate *IrTypeDelegate::get(Type *t) {
   IrFuncTy irFty(tf);
   llvm::Type *ltf =
       DtoFunctionType(tf, irFty, nullptr, Type::tvoid->pointerTo());
-  llvm::Type *types[] = {getVoidPtrType(), getPtrToType(ltf)};
+  llvm::Type *fptr = ltf->getPointerTo(gDataLayout->getProgramAddressSpace());
+  llvm::Type *types[] = {getVoidPtrType(), fptr};
   LLStructType *lt = LLStructType::get(gIR->context(), types, false);
 
   // Could have already built the type as part of a struct forward reference,

tests/codegen/funcptr_harvard_gh4432.d

@@ -0,0 +1,37 @@
+// Tests function pointers/delegates on a Harvard architecture,
+// with code residing in a separate address space.
+
+// REQUIRES: target_AVR
+// RUN: %ldc -mtriple=avr -betterC -output-ll -of=%t.ll %s && FileCheck %s < %t.ll
+// RUN: %ldc -mtriple=avr -betterC -c %s
+
+alias FP = void function();
+alias DG = void delegate();
+
+// CHECK: @_D22funcptr_harvard_gh44328globalFPPFZv = global {{void \(\) addrspace\(1\)\*|ptr addrspace\(1\)}} @_D22funcptr_harvard_gh44323barFZv, align 2
+__gshared FP globalFP = &bar;
+// CHECK: @_D22funcptr_harvard_gh443217globalDataPointerPPFZv = global {{void \(\) addrspace\(1\)\*\*|ptr}} @_D22funcptr_harvard_gh44328globalFPPFZv, align 2
+__gshared FP* globalDataPointer = &globalFP;
+
+// CHECK: define void @_D22funcptr_harvard_gh44323fooFPFZvDQeZv({{.*}} addrspace(1){{\*?}} %fp_arg, { {{.*}} addrspace(1){{\*?}} } %dg_arg) addrspace(1)
+void foo(FP fp, DG dg)
+{
+    // CHECK: call addrspace(1) void %1()
+    fp();
+    // CHECK: call addrspace(1) void %.funcptr
+    dg();
+    // CHECK-NEXT: ret void
+}
+
+void bar()
+{
+    foo(() {}, delegate() {});
+
+    FP fp = &bar;
+    DG dg;
+    dg.funcptr = &bar;
+    foo(fp, dg);
+
+    dg.funcptr = *globalDataPointer;
+    foo(globalFP, dg);
+}