RFR: 8333994: NMT: call stacks should show source information [v5]

[Johan Sjölen]

On Sat, 22 Jun 2024 10:37:27 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Patch adds printing of source file and line number to NMT call stacks that are printed in detail mode. Useful for hunting down leaks.
>
> Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:
> 
>   cleanups

Good job, I found some minor improvements to be had.

src/hotspot/share/nmt/nativeCallStackPrinter.cpp line 40:

> 38:   for (int i = 0; i < NMT_TrackingStackDepth; i++) {
> 39:     const address pc = stack->get_frame(i);
> 40:     if (pc != nullptr) {

Style suggestion: Invert condition and `continue` instead, to reduce indentation of remaining code.

src/hotspot/share/nmt/nativeCallStackPrinter.cpp line 46:

> 44:         stringStream ss(4 * K);
> 45:         stack->print_frame(&ss, pc);
> 46:         const size_t len = strlen(ss.base());

Just use `ss.size()`.

src/hotspot/share/nmt/nativeCallStackPrinter.cpp line 48:

> 46:         const size_t len = strlen(ss.base());
> 47:         char* store = NEW_ARENA_ARRAY(&_text_storage, char, len + 1);
> 48:         strcpy(store, ss.base());

We have the sizes, use `memcpy`.

src/hotspot/share/nmt/nativeCallStackPrinter.cpp line 49:

> 47:         char* store = NEW_ARENA_ARRAY(&_text_storage, char, len + 1);
> 48:         strcpy(store, ss.base());
> 49:         (*cached_frame_text) = store;

Redundant parens

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PR Review: https://git.openjdk.org/jdk/pull/19655#pullrequestreview-2134220333
PR Review Comment: https://git.openjdk.org/jdk/pull/19655#discussion_r1650022361
PR Review Comment: https://git.openjdk.org/jdk/pull/19655#discussion_r1650022628
PR Review Comment: https://git.openjdk.org/jdk/pull/19655#discussion_r1650022710
PR Review Comment: https://git.openjdk.org/jdk/pull/19655#discussion_r1650022744