https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118808
Bug ID: 118808
Summary: operator new allocates wrong size for object of a
template class with two variants
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: bugzi...@little-bat.de
Target Milestone: ---
Created attachment 60433
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=60433&action=edit
gcc version, invocation and .ii file
compiling with arm-none-eabi for cortex-m0plus
compiling for release with -O3 is faulty.
compiling for debug with -Og is correct.
when allocating an object of a template class, which has two separate
definitions for two variants A and B separated by std::enable_if, where variant
B is based on variant A, operator new() only allocates the size for variant A
when instantiating an object of variant B.
the correct constructor is called which overwrites the end of the allocated
memory thus corrupting the heap.
in this example:
virtual base class Canvas
template<ColorMode CM, typename = void> class Pixmap;
// variant A without attributes:
template<ColorMode CM>
class Pixmap<CM, typename std::enable_if_t<is_direct_color(CM)>> : public
Canvas {...}
// variant B with attributes is based on variant A without attributes:
template<ColorMode CM>
class Pixmap<CM, typename std::enable_if_t<is_attribute_mode(CM)>> final :
public Pixmap<ColorMode(get_attrmode(CM))> {...}
the invocation is in line 8286 of the .ii file
