[llvm] [ThinLTO][WPD] Suppress WPD on a class if any superclass is visible in a shared library for index-based WPD (PR #131721)

[Mingming Liu via llvm-commits]

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@@ -0,0 +1,111 @@
+; RUN: rm -rf %t && mkdir %t && cd %t
+
+; Generate unsplit module with summary for ThinLTO index-based WPD.
+; RUN: opt -thinlto-bc -o summary.o %s
+
+; RUN: llvm-dis -o - summary.o
+
+;; TODO: Implement the fix for WPD in regular or hybrid LTO, and add test coverage.
+
+; Index based WPD
+; For `_ZTI7Derived`, the 'llvm-lto2' resolution arguments specifies  `VisibleOutsideSummary` as false
+; and `ExportDynamic` as false. The callsite inside @_ZN4Base8dispatchEv
+; got devirtualized.
+; RUN: llvm-lto2 run summary.o -save-temps -pass-remarks=. \
+; RUN:   -o tmp \
+; RUN:   --whole-program-visibility-enabled-in-lto=true \
+; RUN:   --validate-all-vtables-have-type-infos=true \
+; RUN:   --all-vtables-have-type-infos=true \
+; RUN:   -r=summary.o,__cxa_pure_virtual, \
+; RUN:   -r=summary.o,_ZN8DerivedNC2Ev,x \
+; RUN:   -r=summary.o,_ZN4Base8dispatchEv,px \
+; RUN:   -r=summary.o,_ZN7DerivedC2Ev, \
+; RUN:   -r=summary.o,_ZN8DerivedN5printEv,px \
+; RUN:   -r=summary.o,_ZTS4Base, \
+; RUN:   -r=summary.o,_ZTV8DerivedN,p \
+; RUN:   -r=summary.o,_ZTI8DerivedN,p \
+; RUN:   -r=summary.o,_ZTI4Base, \
+; RUN:   -r=summary.o,_ZTS8DerivedN,p \
+; RUN:   -r=summary.o,_ZTI7Derived, \
+; RUN:   -r=summary.o,_ZTV4Base 2>&1 | FileCheck --allow-empty %s --check-prefix=REMARK
+
+; REMARK: single-impl: devirtualized a call to _ZN8DerivedN5printEv 
+
+; Index based WPD
+; For `_ZTI7Derived`, the 'llvm-lto2' resolution arguments specifies  `VisibleOutsideSummary` as false
+; and `ExportDynamic` as true. The callsite inside @_ZN4Base8dispatchEv won't
+; get devirtualized.
+; RUN: llvm-lto2  run summary.o -save-temps -pass-remarks=. \
+; RUN:   -o tmp \
+; RUN:   --whole-program-visibility-enabled-in-lto=true \
+; RUN:   --validate-all-vtables-have-type-infos=true \
+; RUN:   --all-vtables-have-type-infos=true \
+; RUN:   -r=summary.o,__cxa_pure_virtual, \
+; RUN:   -r=summary.o,_ZN8DerivedNC2Ev,x \
+; RUN:   -r=summary.o,_ZN4Base8dispatchEv,px \
+; RUN:   -r=summary.o,_ZN7DerivedC2Ev, \
+; RUN:   -r=summary.o,_ZN8DerivedN5printEv,px \
+; RUN:   -r=summary.o,_ZTS4Base, \
+; RUN:   -r=summary.o,_ZTV8DerivedN,p \
+; RUN:   -r=summary.o,_ZTI8DerivedN,p \
+; RUN:   -r=summary.o,_ZTI4Base, \
+; RUN:   -r=summary.o,_ZTS8DerivedN,p \
+; RUN:   -r=summary.o,_ZTI7Derived,d \
+; RUN:   -r=summary.o,_ZTV4Base 2>&1 | FileCheck %s --allow-empty --implicit-check-not='single-impl: devirtualized a call to'
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at _ZTV8DerivedN = linkonce_odr hidden constant { [3 x ptr] } { [3 x ptr] [ptr null, ptr @_ZTI8DerivedN, ptr @_ZN8DerivedN5printEv] }, !type !0, !type !1, !type !2, !type !3, !type !4, !type !5, !vcall_visibility !6
+ at _ZTI8DerivedN = linkonce_odr hidden constant { ptr, ptr, ptr } { ptr null, ptr @_ZTS8DerivedN, ptr @_ZTI7Derived }
+ at _ZTS8DerivedN = linkonce_odr hidden constant [10 x i8] c"8DerivedN\00", align 1
+ at _ZTI7Derived = external constant ptr
----------------
mingmingl-llvm wrote:

Good question about the prevailing bit. Let me think about it more and implement the change if needed as a separate patch. 

https://github.com/llvm/llvm-project/pull/131721