From c3a53c0128037b9604741f27ccb095909e758ef9 Mon Sep 17 00:00:00 2001
From: Tomas Lindquist Olsen <tomas.l.olsen@gmail.com>
Date: Tue, 3 Mar 2009 15:08:26 +0100
Subject: [PATCH] Added hasUnalignedFields helper to check if a type has
 unaligned fields - as per request from fvbommel. Result is cached in
 TypeStruct.

---
 dmd/mtype.c         |  3 +++
 dmd/mtype.h         |  5 +++++
 dmd2/mtype.c        |  3 +++
 dmd2/mtype.h        |  5 +++++
 gen/llvmhelpers.cpp | 30 ++++++++++++++++++++++++++++++
 gen/llvmhelpers.h   |  3 +++
 6 files changed, 49 insertions(+)

diff --git a/dmd/mtype.c b/dmd/mtype.c
index f2a4b94a..7ac0714a 100644
--- a/dmd/mtype.c
+++ b/dmd/mtype.c
@@ -4278,6 +4278,9 @@ TypeStruct::TypeStruct(StructDeclaration *sym)
 	: Type(Tstruct, NULL)
 {
     this->sym = sym;
+
+    // LDC
+    this->unaligned = 0;
 }
 
 char *TypeStruct::toChars()
diff --git a/dmd/mtype.h b/dmd/mtype.h
index 0b16aaa8..fd636811 100644
--- a/dmd/mtype.h
+++ b/dmd/mtype.h
@@ -542,6 +542,11 @@ struct TypeStruct : Type
     int hasPointers();
 
     type *toCtype();
+
+    // LDC
+    // cache the hasUnalignedFields check
+    // 0 = not checked, 1 = aligned, 2 = unaligned
+    int unaligned;
 };
 
 struct TypeEnum : Type
diff --git a/dmd2/mtype.c b/dmd2/mtype.c
index abb8739d..2812b59f 100644
--- a/dmd2/mtype.c
+++ b/dmd2/mtype.c
@@ -4929,6 +4929,9 @@ TypeStruct::TypeStruct(StructDeclaration *sym)
 	: Type(Tstruct)
 {
     this->sym = sym;
+
+    // LDC
+    this->unaligned = 0;
 }
 
 char *TypeStruct::toChars()
diff --git a/dmd2/mtype.h b/dmd2/mtype.h
index b33e549a..698f46d4 100644
--- a/dmd2/mtype.h
+++ b/dmd2/mtype.h
@@ -628,6 +628,11 @@ struct TypeStruct : Type
 #endif
 
     type *toCtype();
+
+    // LDC
+    // cache the hasUnalignedFields check
+    // 0 = not checked, 1 = aligned, 2 = unaligned
+    int unaligned;
 };
 
 struct TypeEnum : Type
diff --git a/gen/llvmhelpers.cpp b/gen/llvmhelpers.cpp
index bf05b06b..0f901ecd 100644
--- a/gen/llvmhelpers.cpp
+++ b/gen/llvmhelpers.cpp
@@ -1565,3 +1565,33 @@ bool needsTemplateLinkage(Dsymbol* s)
     return false;
 #endif
 }
+
+//////////////////////////////////////////////////////////////////////////////////////////
+
+bool hasUnalignedFields(Type* t)
+{
+    t = t->toBasetype();
+    if (t->ty != Tstruct)
+        return false;
+
+    TypeStruct* ts = (TypeStruct*)t;
+    if (ts->unaligned)
+        return (ts->unaligned == 2);
+
+    StructDeclaration* sym = ts->sym;
+
+    // go through all the fields and try to find something unaligned
+    ts->unaligned = 2;
+    for (int i = 0; i < sym->fields.dim; i++)
+    {
+        VarDeclaration* f = (VarDeclaration*)sym->fields.data[i];
+        unsigned a = f->type->alignsize() - 1;
+        if (((f->offset + a) & ~a) != f->offset)
+            return true;
+        else if (f->type->toBasetype()->ty == Tstruct && hasUnalignedFields(f->type))
+            return true;
+    }
+
+    ts->unaligned = 1;
+    return false;
+}
diff --git a/gen/llvmhelpers.h b/gen/llvmhelpers.h
index 487c0b64..3cf5b47d 100644
--- a/gen/llvmhelpers.h
+++ b/gen/llvmhelpers.h
@@ -114,6 +114,9 @@ bool mustDefineSymbol(Dsymbol* s);
 // returns true if the symbol needs template linkage, or just external
 bool needsTemplateLinkage(Dsymbol* s);
 
+// returns true if there is any unaligned type inside the aggregate
+bool hasUnalignedFields(Type* t);
+
 ////////////////////////////////////////////
 // gen/tocall.cpp stuff below
 ////////////////////////////////////////////