x86: Only skip empty structs on OS X

ldc-developers · Sep 16, 2015 · 6f83cb2 · 6f83cb2
1 parent c00813d
commit 6f83cb2
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Showing 2 changed files with 25 additions and 11 deletions.
diff --git a/gen/abi-x86.cpp b/gen/abi-x86.cpp
@@ -215,6 +215,31 @@ struct X86TargetABI : TargetABI
             // IMPLICIT PARAMETERS
 
             // EXPLICIT PARAMETERS
+
+            // Clang does not pass empty structs, while it seems that GCC does,
+            // at least on Linux x86.
+            if (isOSX)
+            {
+                size_t i = 0;
+                while (i < fty.args.size())
+                {
+                    Type *type = fty.args[i]->type->toBasetype();
+                    if (type->ty == Tstruct)
+                    {
+                        // Do not pass empty structs at all for C++ ABI compatibility.
+                        // Tests with clang reveal that more complex "empty" types, for
+                        // example a struct containing an empty struct, are not
+                        // optimized in the same way.
+                        StructDeclaration *sd = static_cast<TypeStruct *>(type)->sym;
+                        if (sd->fields.empty())
+                        {
+                            fty.args.erase(fty.args.begin() + i);
+                            continue;
+                        }
+                    }
+                    ++i;
+                }
+            }
         }
     }
 };

diff --git a/gen/functions.cpp b/gen/functions.cpp
@@ -164,17 +164,6 @@ llvm::FunctionType* DtoFunctionType(Type* type, IrFuncTy &irFty, Type* thistype,
         }
         else if (!passPointer)
         {
-            if (loweredDType->toBasetype()->ty == Tstruct)
-            {
-                // Do not pass empty structs at all for C++ ABI compatibility.
-                // Tests with clang reveal that more complex "empty" types, for
-                // example a struct containing an empty struct, are not
-                // optimized in the same way.
-                StructDeclaration *sd =
-                    static_cast<TypeStruct*>(loweredDType->toBasetype())->sym;
-                if (sd->fields.empty()) continue;
-            }
-
             if (abi->passByVal(loweredDType))
             {
                 attrBuilder.add(LDC_ATTRIBUTE(ByVal));