[PATCH] D79719: [AIX] Implement AIX special alignment rule about double/long double

[Eli Friedman via Phabricator via cfe-commits]

efriedma added a comment.

This approach seems to reflect the consensus from the mailing list.



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Comment at: clang/include/clang/AST/RecordLayout.h:74
+  /// The maximum allowed field alignment. This is set by #pragma pack.
+  CharUnits MaxFieldAlignment;
+
----------------
If we have to keep around extra data anyway, probably better to add a field for the preferred alignment, so we can keep the preferred alignment handling together.


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Comment at: clang/lib/AST/ASTContext.cpp:2518
+      (T->isSpecificBuiltinType(BuiltinType::LongDouble) &&
+       getTargetInfo().getTriple().isOSAIX()))
     // Don't increase the alignment if an alignment attribute was specified on a
----------------
We try to avoid OS-specific checks here.  But I'm not sure what this should look like on other targets.


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Comment at: clang/lib/AST/ASTContext.cpp:2527
+    // as its first member.
+    if (getTargetInfo().getTriple().isOSAIX()) {
+      const RecordDecl *RD = RT->getDecl();
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I'd prefer to centralize the check for "AIX struct layout" in one place, as opposed to putting checks for AIX targets in multiple places.


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Comment at: clang/lib/AST/RecordLayoutBuilder.cpp:3438
+                                C.getPreferredTypeAlign(RD->getTypeForDecl()))
+                               .getQuantity());
 
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Please don't make the dumping code lie about the "align".  If you want to dump the preferred alignment in addition, that would be fine.


Repository:
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  https://reviews.llvm.org/D79719/new/

https://reviews.llvm.org/D79719