RFR: 7904115: Fix for AIX test case failures due to incorrect alignment for double and pointer

[Jorn Vernee]

On Thu, 20 Nov 2025 11:20:46 GMT, Varada M <varadam at openjdk.org> wrote:

> Total of 10 test failures observed on AIX:
> jtreg/generator/nestedTypes/TestNestedTypesUnsupported.java 
> jtreg/generator/test8246400/LibTest8246400Test.java 
> jtreg/generator/test8258605/LibTest8258605Test.java 
> jtreg/generator/test8261511/Test8261511.java 
> jtreg/generator/testStruct/LibStructTest.java 
> testng/org/openjdk/jextract/test/toolprovider/ConstantsTest.java 
> testng/org/openjdk/jextract/test/toolprovider/IncompleteArrayTest.java 
> testng/org/openjdk/jextract/test/toolprovider/Test8240811.java 
> testng/org/openjdk/jextract/test/toolprovider/TestClassGeneration.java 
> testng/org/openjdk/jextract/test/toolprovider/nestedAnonOffset/TestNestedAnonOffset.java
> 
> This PR fixes AIX specific layout generation issues related to incorrect alignment double and pointer types.
> 1. Structs containing double fields fail with:
>     i. Unsupported layout: 4%D8
>     ii. Invalid alignment constraint for member layout
>     double in AIX structs has size 8 but alignment 4 (except as first field). AIX specific handling for C_DOUBLE computes the     correct alignment.
> 
> 2. Clang was detected as 32-bit due to missing -m64 during macro extraction, causing inconsistent macros. This caused jextract to interpret pointer constants incorrectly, leading to failures like:
> expected [-1] but found [4294967295]
> 
> 3. TestNestedAnonOffset.java test failed on AIX because it also expects more padding similar to platforms like windows and linux
> 
> 
> After the patch jtreg tests passes successfully.
> 
> JBS: [CODETOOLS-7904115](https://bugs.openjdk.org/browse/CODETOOLS-7904115)

src/main/java/org/openjdk/jextract/impl/ClassSourceBuilder.java line 269:

> 267:                     } else {
> 268:                         yield alignIfNeeded(runtimeHelperName() + ".C_DOUBLE", 4, align);
> 269:                     }

Why are there 2 cases here?

src/main/java/org/openjdk/jextract/impl/Options.java line 92:

> 90:             if (TypeImpl.IS_AIX) {
> 91:                 clangArgs.add("-m64");
> 92:             }

This doesn't look like the right place to add this, as the `-m64` flag would be added for each clang argument.

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PR Review Comment: https://git.openjdk.org/jextract/pull/296#discussion_r2546292527
PR Review Comment: https://git.openjdk.org/jextract/pull/296#discussion_r2546280367