[Bug]: error: ‘MEM[(struct AMFVariantStruct *)_2 + 40B].D.5758.stringValue’ may be used uninitialized

[RandUser123sa]

Describe the bug
Compilation issue, unable to build samples with make all BUILD_TYPE=rel

To Reproduce
Steps to reproduce the behavior:
cd amf/public/samples
make all BUILD_TYPE=rel

Setup (please complete the following information):

• OS: [Slackware 15 x86_64]
• Driver Version [e.g. 22.2.1]
• GPU [ RX 7900 XTX]
• Which component has the issue [Compilation issue]

Debug Log (please upload or paste):

In function ‘AMFVariantClear’,
    inlined from ‘__dt_base ’ at ../../../../public/common/../include/core/Variant.h:253:40,
    inlined from ‘__dt_base ’ at /usr/include/c++/14.2.0/bits/stl_pair.h:284:12,
    inlined from ‘destroy_at’ at /usr/include/c++/14.2.0/bits/stl_construct.h:88:18,
    inlined from ‘destroy’ at /usr/include/c++/14.2.0/bits/alloc_traits.h:556:19,
    inlined from ‘_M_destroy_node’ at /usr/include/c++/14.2.0/bits/stl_tree.h:621:24,
    inlined from ‘_M_drop_node’ at /usr/include/c++/14.2.0/bits/stl_tree.h:629:17,
    inlined from ‘__dt_base ’ at /usr/include/c++/14.2.0/bits/stl_tree.h:1639:23,
    inlined from ‘_M_emplace_hint_unique.constprop.isra’ at /usr/include/c++/14.2.0/bits/stl_tree.h:2463:7:
../../../../public/common/../include/core/Variant.h:602:30: error: ‘MEM[(struct AMFVariantStruct *)_2 + 40B].D.5758.stringValue’ may be used uninitialized [-Werror=maybe-uninitialized]
  602 |             amf_variant_free(AMFVariantString(pVariant));
      |                              ^
../../../../public/common/../include/core/Variant.h:607:30: error: ‘MEM[(struct AMFVariantStruct *)_2 + 40B].D.5758.wstringValue’ may be used uninitialized [-Werror=maybe-uninitialized]
  607 |             amf_variant_free(AMFVariantWString(pVariant));
      |                              ^
../../../../public/common/../include/core/Variant.h:612:17: error: ‘MEM[(struct AMFVariantStruct *)_2 + 40B].D.5758.pInterface’ may be used uninitialized [-Werror=maybe-uninitialized]
  612 |             if (AMFVariantInterface(pVariant) != NULL)
      |                 ^
lto1: all warnings being treated as errors
lto-wrapper: fatal error: g++ returned 1 exit status

[RandUser123sa]

The same error on 1.4.36

make[1]: Leaving directory '/root/amdgpu/amf/AMF-1.4.36/amf/public/samples/CPPSamples/SimplePA'
In function ‘AMFVariantClear’,
    inlined from ‘__dt_base ’ at ../../../../public/common/../include/core/Variant.h:253:40,
    inlined from ‘__dt_base ’ at /usr/include/c++/14.2.0/bits/stl_pair.h:284:12,
    inlined from ‘destroy_at’ at /usr/include/c++/14.2.0/bits/stl_construct.h:88:18,
    inlined from ‘destroy’ at /usr/include/c++/14.2.0/bits/alloc_traits.h:556:19,
    inlined from ‘_M_destroy_node’ at /usr/include/c++/14.2.0/bits/stl_tree.h:621:24,
    inlined from ‘_M_drop_node’ at /usr/include/c++/14.2.0/bits/stl_tree.h:629:17,
    inlined from ‘__dt_base ’ at /usr/include/c++/14.2.0/bits/stl_tree.h:1639:23,
    inlined from ‘_M_emplace_hint_unique.constprop.isra’ at /usr/include/c++/14.2.0/bits/stl_tree.h:2463:7:
../../../../public/common/../include/core/Variant.h:602:30: error: ‘MEM[(struct AMFVariantStruct *)_2 + 40B].D.5758.stringValue’ may be used uninitialized [-Werror=maybe-uninitialized]
  602 |             amf_variant_free(AMFVariantString(pVariant));
      |                              ^
../../../../public/common/../include/core/Variant.h:607:30: error: ‘MEM[(struct AMFVariantStruct *)_2 + 40B].D.5758.wstringValue’ may be used uninitialized [-Werror=maybe-uninitialized]
  607 |             amf_variant_free(AMFVariantWString(pVariant));
      |                              ^
../../../../public/common/../include/core/Variant.h:612:17: error: ‘MEM[(struct AMFVariantStruct *)_2 + 40B].D.5758.pInterface’ may be used uninitialized [-Werror=maybe-uninitialized]
  612 |             if (AMFVariantInterface(pVariant) != NULL)
      |                 ^
make[1]: Leaving directory '/root/amdgpu/amf/AMF-1.4.36/amf/public/samples/CPPSamples/SimpleEncoder'
make[1]: Leaving directory '/root/amdgpu/amf/AMF-1.4.36/amf/public/samples/CPPSamples/SimpleConverter'
In function ‘AMFVariantClear’,
    inlined from ‘__dt_base ’ at ../../../../public/common/../include/core/Variant.h:253:40,
    inlined from ‘__dt_base ’ at /usr/include/c++/14.2.0/bits/stl_pair.h:284:12,
    inlined from ‘destroy_at’ at /usr/include/c++/14.2.0/bits/stl_construct.h:88:18,
    inlined from ‘destroy’ at /usr/include/c++/14.2.0/bits/alloc_traits.h:556:19,
    inlined from ‘_M_destroy_node’ at /usr/include/c++/14.2.0/bits/stl_tree.h:621:24,
    inlined from ‘_M_drop_node’ at /usr/include/c++/14.2.0/bits/stl_tree.h:629:17,
    inlined from ‘__dt_base ’ at /usr/include/c++/14.2.0/bits/stl_tree.h:1639:23,
    inlined from ‘_M_emplace_hint_unique.constprop.isra’ at /usr/include/c++/14.2.0/bits/stl_tree.h:2463:7:
../../../../public/common/../include/core/Variant.h:602:30: error: ‘MEM[(struct AMFVariantStruct *)_2 + 40B].D.5340.stringValue’ may be used uninitialized [-Werror=maybe-uninitialized]
  602 |             amf_variant_free(AMFVariantString(pVariant));
      |                              ^
../../../../public/common/../include/core/Variant.h:607:30: error: ‘MEM[(struct AMFVariantStruct *)_2 + 40B].D.5340.wstringValue’ may be used uninitialized [-Werror=maybe-uninitialized]
  607 |             amf_variant_free(AMFVariantWString(pVariant));
      |                              ^
../../../../public/common/../include/core/Variant.h:612:17: error: ‘MEM[(struct AMFVariantStruct *)_2 + 40B].D.5340.pInterface’ may be used uninitialized [-Werror=maybe-uninitialized]
  612 |             if (AMFVariantInterface(pVariant) != NULL)
      |                 ^
make[1]: Leaving directory '/root/amdgpu/amf/AMF-1.4.36/amf/public/samples/CPPSamples/SimpleDecoder'
lto1: all warnings being treated as errors

[rhutsAMD]

What compiler and version are you using? As an experiment, could you try to set the pointers to NULL inside AMFVariantInit like so:

    static AMF_INLINE AMF_RESULT AMF_CDECL_CALL AMFVariantInit(AMFVariantStruct* pVariant)
    {
        AMF_VARIANT_RETURN_IF_INVALID_POINTER(pVariant);
        pVariant->type = AMF_VARIANT_EMPTY;
        pVariant->pInterface = NULL;
        pVariant->stringValue = NULL;
        pVariant->wstringValue = NULL;
        return AMF_OK;
    }

[RandUser123sa]

Hi @rhutsAMD,

the patch solve the problem. Thank you. I'm using g++ (GCC) 14.2.0