[BoundsSafety] Don't bind lvalues with temporary locations #10969
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This should fix a miscompilation bug found during adoption. When a base is lvalue and is wrapped in OVE, the compiler incorrectly creates a temporary and maps its address to the lvalue instead of the actual address of the lvalue. The solution is to emit lvalue directly instead of creating extra temporary. rdar://146329029
rapidsna
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delcypher,
hnrklssn,
patrykstefanski and
apple-fcloutier
rapidsna
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clang:bounds-safety
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@swift-ci test llvm |
patrykstefanski
approved these changes
Jul 9, 2025
…ing in order to avoid non-determinism The execution order of arguments is unspecified in C++. Directly passing calls that emit code as arguments caused non-deterministic order in the generated instructions and test failures in different platforms.
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@swift-ci test llvm |
rapidsna
commented
Jul 9, 2025
| ElemBitCast); | ||
| : nullptr; | ||
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| EmitWidePointerToDest(E->getType(), Ptr, Upper, Lower, ElemBitCast); |
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@patrykstefanski I suspect this was what caused the Linux code test failures where getelementptr instructions were emitted in a different order on Linux.
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Nice find. After landing this we should try re-enabling the tests we disabled on Linux.
delcypher
reviewed
Jul 9, 2025
| for (auto *OVE : MSE->opaquevalues()) { | ||
| if (CodeGenFunction::OpaqueValueMappingData::shouldBindAsLValue(OVE)) { | ||
| RValue PtrRV = EmitAnyExpr(OVE->getSourceExpr()); | ||
| LValue LV = MakeAddrLValue(PtrRV.getAggregateAddress(), OVE->getType()); |
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The EmitAnyExpr() function creates a temporary slot for aggregates.
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Maybe worth explicitly mentioning that in the commit message for clarity.
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@swift-ci test llvm |
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Test failures seem unrelated to this change 12:53:24 ******************** |
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… temporary locations (#11469) - Solution from #10969: This should fix a miscompilation bug found during adoption. When a base is lvalue and is wrapped in OVE, the compiler created a temporary and incorrectly mapped the temporary's address as the lvalue instead of the actual address of the lvalue. The solution is to emit lvalue directly instead of creating extra temporary. - Issue with the solution: The issue #10969 got originally reverted due "error: cannot compile this l-value expression yet" occurred when __terminated_by_to_indexable is wrapped in an OVE. - Fix for the new issue with __terminated_by_to_indexable: The fix is to implement "TerminatedByToIndexableExprLValue" so the codegen can also emit as if it's an lvalue. rdar://146329029
rapidsna
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Sep 26, 2025
… temporary locations (#11469) - Solution from #10969: This should fix a miscompilation bug found during adoption. When a base is lvalue and is wrapped in OVE, the compiler created a temporary and incorrectly mapped the temporary's address as the lvalue instead of the actual address of the lvalue. The solution is to emit lvalue directly instead of creating extra temporary. - Issue with the solution: The issue #10969 got originally reverted due "error: cannot compile this l-value expression yet" occurred when __terminated_by_to_indexable is wrapped in an OVE. - Fix for the new issue with __terminated_by_to_indexable: The fix is to implement "TerminatedByToIndexableExprLValue" so the codegen can also emit as if it's an lvalue. rdar://146329029 (cherry picked from commit 04da1af)
rapidsna
added a commit
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Sep 27, 2025
… temporary locations (#11469) (#11504) - Solution from #10969: This should fix a miscompilation bug found during adoption. When a base is lvalue and is wrapped in OVE, the compiler created a temporary and incorrectly mapped the temporary's address as the lvalue instead of the actual address of the lvalue. The solution is to emit lvalue directly instead of creating extra temporary. - Issue with the solution: The issue #10969 got originally reverted due "error: cannot compile this l-value expression yet" occurred when __terminated_by_to_indexable is wrapped in an OVE. - Fix for the new issue with __terminated_by_to_indexable: The fix is to implement "TerminatedByToIndexableExprLValue" so the codegen can also emit as if it's an lvalue. rdar://146329029 (cherry picked from commit 04da1af)
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This should fix a miscompilation bug found during adoption. When a base is lvalue and is wrapped in OVE, the compiler created a temporary and incorrectly mapped the temporary's address as the lvalue instead of the actual address of the lvalue.
The solution is to emit lvalue directly instead of creating extra temporary.
rdar://146329029