https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102101
Bug ID: 102101
Summary: Another spurious -Warray-bounds
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: sbergman at redhat dot com
CC: msebor at gcc dot gnu.org
Target Milestone: ---
On recent trunk (basepoints/gcc-12-3135-gdb3d4129b6f):
> $ cat test.cc
> #include <cstddef>
> #include <vector>
> long dummy();
> void * rtl_allocateMemory();
> struct XInterface {
> virtual void acquire() = 0;
> void release();
> };
> struct WeakComponentImplHelperBase: XInterface {
> static void * operator new(std::size_t) { return rtl_allocateMemory(); }
> static void operator delete(void *);
> virtual void acquire();
> };
> struct XPrimitive2D: XInterface {};
> struct PartialWeakComponentImplHelper: WeakComponentImplHelperBase,
> XPrimitive2D {
> void acquire() { WeakComponentImplHelperBase::acquire(); }
> };
> struct FillHatchPrimitive2D: PartialWeakComponentImplHelper {
> FillHatchPrimitive2D();
> };
> struct Reference {
> XInterface * _pInterface;
> ~Reference() { if (_pInterface) _pInterface->release(); }
> Reference(XPrimitive2D * pInterface) {
> _pInterface = static_cast<XInterface *>(static_cast<void
> *>(pInterface));
> if (_pInterface) _pInterface->acquire();
> }
> };
> struct Size {
> Size();
> bool IsEmpty() const { return nA || nB; }
> int nA, nB;
> };
> struct PropertyHolder {
> bool getLineOrFillActive() { return mbLineColor || mbFillColor; }
> bool mbLineColor, mbFillColor;
> };
> struct NonOverlappingFillGradientPrimitive2D: FillHatchPrimitive2D {
> void create2DDecomposition() { if (dummy()) dummy(); }
> NonOverlappingFillGradientPrimitive2D() {}
> };
> void implInterpretMetafile(PropertyHolder & rPropertyHolders) {
> int nCount = dummy();
> int nAction = 0;
> switch(dummy()) {
> case 0:
> while (0 == dummy() && nAction < nCount) {}
> case 1:
> while (0 == dummy() && nAction < nCount) {}
> case 2:
> if (rPropertyHolders.getLineOrFillActive()) {
> Size rRectangle;
> if (rRectangle.IsEmpty()) {
> Size aRange;
> if (aRange.IsEmpty()) dummy();
> }
> }
> case 3:
> if (rPropertyHolders.getLineOrFillActive()) {
> Size rRectangle;
> if (rRectangle.IsEmpty()) {
> Size aRange;
> if (aRange.IsEmpty()) dummy();
> }
> }
> case 4:
> if (rPropertyHolders.getLineOrFillActive()) {
> Size rRectangle;
> if (rRectangle.IsEmpty()) {
> Size aRange;
> if (aRange.IsEmpty()) dummy();
> }
> }
> case 5:
> if (rPropertyHolders.getLineOrFillActive()) {
> Size rRectangle;
> if (rRectangle.IsEmpty()) {
> Size aRange;
> if (aRange.IsEmpty()) dummy();
> }
> }
> case 6:
> if (rPropertyHolders.getLineOrFillActive()) {
> Size rRectangle;
> if (rRectangle.IsEmpty()) {
> Size aRange;
> if (aRange.IsEmpty()) dummy();
> }
> }
> case 7:
> if (rPropertyHolders.getLineOrFillActive()) dummy();
> case 8:
> if (rPropertyHolders.getLineOrFillActive()) dummy();
> case 9:
> if (rPropertyHolders.getLineOrFillActive()) dummy();
> case 10:
> if (rPropertyHolders.getLineOrFillActive()) dummy();
> case 11:
> if (rPropertyHolders.getLineOrFillActive()) dummy();
> case 12:
> {
> int nTextLength = dummy();
> int nTextIndex = dummy();
> int nStringLength = dummy();
> if (nTextLength + nTextIndex > nStringLength) {
> nTextLength = nTextIndex > nStringLength ? 0 : nStringLength
> - nTextIndex;
> }
> if (nTextLength && dummy()) {
> std::vector< double > aDXArray;
> aDXArray.reserve(nTextLength);
> }
> }
> case 13:
> if (dummy() && dummy())
> if (dummy() && dummy()) dummy();
> case 14:
> {
> Size rRectangle;
> if (rRectangle.IsEmpty() && dummy()) dummy();
> }
> case 15:
> Reference(new FillHatchPrimitive2D);
> }
> }
> $ g++ -D_GLIBCXX_DEBUG -Werror -Warray-bounds -O2 -c test.cc
> In member function ‘virtual void PartialWeakComponentImplHelper::acquire()’,
> inlined from ‘Reference::Reference(XPrimitive2D*)’ at test.cc:26:46,
> inlined from ‘void implInterpretMetafile(PropertyHolder&)’ at
> test.cc:122:9:
> test.cc:16:58: error: array subscript 0 is outside array bounds of
> ‘XPrimitive2D [1152921504606846975]’ [-Werror=array-bounds]
> 16 | void acquire() { WeakComponentImplHelperBase::acquire(); }
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
> test.cc: In function ‘void implInterpretMetafile(PropertyHolder&)’:
> test.cc:15:8: note: at offset -8 into object
> ‘PartialWeakComponentImplHelper::<anonymous>’ of size 8
> 15 | struct PartialWeakComponentImplHelper: WeakComponentImplHelperBase,
> XPrimitive2D {
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1plus: all warnings being treated as errors
(The test code only fails with the _GLIBCXX_DEBUG version of <vector>, which is
probably just another random coincidental part of this reproducer, and I didn't
feel like trying to minimize it even further.)
