Hi,
> Alignment is written to TypeInfo, I don't think it should ever be
> zero. That would mean that it isn't being generated by the compiler,
> or read by the library correctly, so something else is amiss.
it took me a while to see that in libphobos/libdruntime/object.d
override @property size_t talign() nothrow pure const {return m_align;}
returns a size_t but m_align is a uint. The type info seems to be
stored in memory by the compiler and writes a GCC "sizetype". When
using it, we only emit a 4-byte read which loads the first half of the
stored 8 bytes. This will work on a little-endian machine but fail on
big endian.
I'd hope it is safe to change m_align's type to size_t since, as far as
I can tell, the compiler will always write 8 bytes and the memory layout
will not be changed by that.
Does this [1] look reasonable?
Regards
Robin
---
[1]
diff --git a/gcc/d/typeinfo.cc b/gcc/d/typeinfo.cc
index dac66acdcd4..1bd94c33e82 100644
--- a/gcc/d/typeinfo.cc
+++ b/gcc/d/typeinfo.cc
@@ -954,7 +954,7 @@ public:
StructFlags m_flags;
void function(void*) xdtor;
void function(void*) xpostblit;
- uint m_align;
+ size_t m_align;
version (X86_64)
TypeInfo m_arg1;
TypeInfo m_arg2;
@@ -1032,7 +1032,7 @@ public:
else
this->layout_field (null_pointer_node);
- /* uint m_align; */
+ /* size_t m_align; */
this->layout_field (size_int (ti->alignsize ()));
if (global.params.is64bit)
diff --git a/libphobos/libdruntime/object.d b/libphobos/libdruntime/object.d
index 38bd0ae1f6b..bb821bf7040 100644
--- a/libphobos/libdruntime/object.d
+++ b/libphobos/libdruntime/object.d
@@ -1226,7 +1226,7 @@ class TypeInfo_Struct : TypeInfo
}
void function(void*) xpostblit;
- uint m_align;
+ size_t m_align;
override @property immutable(void)* rtInfo() const { return m_RTInfo; }
