windows: alignstack=16 on every function

See #302

1 files changed, 19 insertions, 0 deletions

diff --git a/src/codegen.cpp b/src/codegen.cpp
index f0826e3c49..18d19e39f0 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -290,6 +290,15 @@ static void addLLVMAttrStr(LLVMValueRef val, LLVMAttributeIndex attr_index,
     LLVMAddAttributeAtIndex(val, attr_index, llvm_attr);
 }
 
+static void addLLVMAttrInt(LLVMValueRef val, LLVMAttributeIndex attr_index,
+        const char *attr_name, uint64_t attr_val)
+{
+    unsigned kind_id = LLVMGetEnumAttributeKindForName(attr_name, strlen(attr_name));
+    assert(kind_id != 0);
+    LLVMAttributeRef llvm_attr = LLVMCreateEnumAttribute(LLVMGetGlobalContext(), kind_id, attr_val);
+    LLVMAddAttributeAtIndex(val, attr_index, llvm_attr);
+}
+
 static void addLLVMFnAttr(LLVMValueRef fn_val, const char *attr_name) {
     return addLLVMAttr(fn_val, -1, attr_name);
 }
@@ -298,6 +307,10 @@ static void addLLVMFnAttrStr(LLVMValueRef fn_val, const char *attr_name, const c
     return addLLVMAttrStr(fn_val, -1, attr_name, attr_val);
 }
 
+static void addLLVMFnAttrInt(LLVMValueRef fn_val, const char *attr_name, uint64_t attr_val) {
+    return addLLVMAttrInt(fn_val, -1, attr_name, attr_val);
+}
+
 static void addLLVMArgAttr(LLVMValueRef arg_val, unsigned param_index, const char *attr_name) {
     return addLLVMAttr(arg_val, param_index + 1, attr_name);
 }
@@ -439,6 +452,12 @@ static LLVMValueRef fn_llvm_value(CodeGen *g, FnTableEntry *fn_table_entry) {
         }
     }
 
+    if (g->zig_target.os == ZigLLVM_Win32 && g->zig_target.arch.arch == ZigLLVM_x86_64 &&
+        fn_type->data.fn.fn_type_id.cc != CallingConventionNaked)
+    {
+        addLLVMFnAttrInt(fn_table_entry->llvm_value, "alignstack", 16);
+    }
+
     addLLVMFnAttr(fn_table_entry->llvm_value, "nounwind");
     addLLVMFnAttr(fn_table_entry->llvm_value, "nobuiltin");
     if (g->build_mode == BuildModeDebug && fn_table_entry->fn_inline != FnInlineAlways) {