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8310906: Fix -Wconversion warnings in runtime, oops and some code header files. #14659

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@coleenp coleenp commented Jun 26, 2023

More casts for size of address differences in same code space, checked_casts<> and type changes to fix -Wconversion warnings. See CR for details.
Tested with tier1-4.


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  • JDK-8310906: Fix -Wconversion warnings in runtime, oops and some code header files. (Enhancement - P4)

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bridgekeeper bot commented Jun 26, 2023

👋 Welcome back coleenp! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

@openjdk openjdk bot added the rfr Pull request is ready for review label Jun 26, 2023
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@coleenp The following labels will be automatically applied to this pull request:

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@openjdk openjdk bot added serviceability serviceability-dev@openjdk.org hotspot hotspot-dev@openjdk.org labels Jun 26, 2023
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@@ -217,7 +217,7 @@ template<typename FKind> frame ThawBase::new_stack_frame(const frame& hf, frame&
intptr_t* heap_sp = hf.unextended_sp();
// If caller is interpreted it already made room for the callee arguments
int overlap = caller.is_interpreted_frame() ? ContinuationHelper::InterpretedFrame::stack_argsize(hf) : 0;
const int fsize = ContinuationHelper::InterpretedFrame::frame_bottom(hf) - hf.unextended_sp() - overlap;
const int fsize = checked_cast<int>(ContinuationHelper::InterpretedFrame::frame_bottom(hf) - hf.unextended_sp() - overlap);
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This line computes the size of the unextended frame minus the overlap that exists if the callee is using arguments in the caller’s frame. So this value is lower or equal to the frame’ size which is encoded with an int. I don't think a checked_cast is required here. This applies to the x86 version too.

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I'll make this change in the new PR. I'm going to redo the address calculations to call a function rather than the casts.

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coleenp commented Jun 26, 2023

After some offline conversation with Ioi, we thought of a better way to express these pointer subtractions returning int, so I'm going to close this PR and open a new one with at least these changed with that new function.

// delta usually called with pointers or intptr_t that returns an int
// used for code buffer and other nearby address calculations.
// This allows the left side to be less than the right side.
template <typename T>
inline int delta_as_int(const volatile T left, const volatile T right) {
  return checked_cast<int>(left - right);
} 

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