Look at the Prevailing bit as opposed to ExportDynamic bit, update

regression test

Author: mingmingl-llvm

llvm/lib/LTO/LTO.cpp

@@ -1315,7 +1315,7 @@ Error LTO::runRegularLTO(AddStreamFn AddStream) {
   auto IsVisibleToRegularObj = [&](StringRef name) {
     auto It = GlobalResolutions->find(name);
     return (It == GlobalResolutions->end() ||
-            It->second.VisibleOutsideSummary || It->second.ExportDynamic);
+            It->second.VisibleOutsideSummary || !It->second.Prevailing);
   };
 
   // If allowed, upgrade public vcall visibility metadata to linkage unit
@@ -1906,7 +1906,7 @@ Error LTO::runThinLTO(AddStreamFn AddStream, FileCache Cache,
     auto IsVisibleToRegularObj = [&](StringRef name) {
       auto It = GlobalResolutions->find(name);
       return (It == GlobalResolutions->end() ||
-              It->second.VisibleOutsideSummary || It->second.ExportDynamic);
+              It->second.VisibleOutsideSummary || !It->second.Prevailing);
     };
 
     getVisibleToRegularObjVtableGUIDs(ThinLTO.CombinedIndex,

llvm/test/ThinLTO/X86/nodevirt_export_dynamic.ll renamed to llvm/test/ThinLTO/X86/devirt_prevailing.ll

@@ -1,17 +1,17 @@
 ; RUN: rm -rf %t && mkdir %t && cd %t
 
-; Tests that devirtualization is suppressed on a class when its compatible
-; class could be referenced from dynamic linker that is not visible to the
-; linker.
+; Tests that devirtualization is suppressed on a class when the LTO unit doesn't
+; have the prevailing definition of the class.
 
 ; Generate unsplit module with summary for ThinLTO index-based WPD.
 ; RUN: opt -thinlto-bc -o summary.o %s
 
 ; Index based WPD
-; For `_ZTI7Derived`, the 'llvm-lto2' resolution arguments specifies  `VisibleOutsideSummary` as false
-; and `ExportDynamic` as false. The callsite inside @_ZN4Base8dispatchEv
-; got devirtualized.
+; The callsite inside @_ZN4Base8dispatchEv gets devirtualized when symbol
+; resolution shows there is a prevailing definition of `_ZTI7Derived` in the
+; LTO unit.
 ; RUN: llvm-lto2 run summary.o -save-temps -pass-remarks=. \
+; RUN:   -thinlto-threads=1 \
 ; RUN:   -o tmp \
 ; RUN:   --whole-program-visibility-enabled-in-lto=true \
 ; RUN:   --validate-all-vtables-have-type-infos=true \
@@ -24,15 +24,16 @@
 ; RUN:   -r=summary.o,_ZTV8DerivedN,p \
 ; RUN:   -r=summary.o,_ZTI8DerivedN,p \
 ; RUN:   -r=summary.o,_ZTS8DerivedN,p \
-; RUN:   -r=summary.o,_ZTI7Derived, \
+; RUN:   -r=summary.o,_ZTI7Derived,p \
 ; RUN:   2>&1 | FileCheck --allow-empty %s --check-prefix=REMARK
 
 
 ; 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.
+; The callsite inside @_ZN4Base8dispatchEv remains indirect and not de-virtualized
+; when symbol resolution shows there isn't a prevailing definition of
+; `_ZTI7Derived` in the LTO unit.
 ; RUN: llvm-lto2  run summary.o -save-temps -pass-remarks=. \
+; RUN:   -thinlto-threads=1 \
 ; RUN:   -o tmp \
 ; RUN:   --whole-program-visibility-enabled-in-lto=true \
 ; RUN:   --validate-all-vtables-have-type-infos=true \
@@ -45,13 +46,14 @@
 ; RUN:   -r=summary.o,_ZTV8DerivedN,p \
 ; RUN:   -r=summary.o,_ZTI8DerivedN,p \
 ; RUN:   -r=summary.o,_ZTS8DerivedN,p \
-; RUN:   -r=summary.o,_ZTI7Derived,d \
+; RUN:   -r=summary.o,_ZTI7Derived, \
 ; RUN:   2>&1 | FileCheck %s --allow-empty --implicit-check-not='single-impl: devirtualized a call to'
 
-
-; Hybrid LTO WPD
+; Repeat the above tests for WPD in hybrid LTO.
 ; RUN: opt  --thinlto-bc --thinlto-split-lto-unit -o hybrid.o %s
+
 ; RUN: llvm-lto2 run hybrid.o -save-temps -pass-remarks=. \
+; RUN:   -thinlto-threads=1 \
 ; RUN:   -o hybrid \
 ; RUN:   --whole-program-visibility-enabled-in-lto=true \
 ; RUN:   --validate-all-vtables-have-type-infos=true \
@@ -61,17 +63,18 @@
 ; RUN:   -r=hybrid.o,_ZN4Base8dispatchEv,px \
 ; RUN:   -r=hybrid.o,_ZN7DerivedC2Ev, \
 ; RUN:   -r=hybrid.o,_ZN8DerivedN5printEv,px \
-; RUN:   -r=hybrid.o,_ZTV8DerivedN,p \
-; RUN:   -r=hybrid.o,_ZTI8DerivedN,p \
+; RUN:   -r=hybrid.o,_ZTV8DerivedN, \
+; RUN:   -r=hybrid.o,_ZTI8DerivedN, \
 ; RUN:   -r=hybrid.o,_ZTS8DerivedN,p \
-; RUN:   -r=hybrid.o,_ZTI7Derived, \
-; RUN:   -r=hybrid.o,_ZN8DerivedN5printEv,px \
+; RUN:   -r=hybrid.o,_ZTI7Derived,p \
+; RUN:   -r=hybrid.o,_ZN8DerivedN5printEv, \
 ; RUN:   -r=hybrid.o,_ZTV8DerivedN,p \
 ; RUN:   -r=hybrid.o,_ZTI8DerivedN,p \
 ; RUN:   2>&1 | FileCheck --allow-empty %s --check-prefix=REMARK
 
-; Hybrid LTO WPD
+
 ; RUN: llvm-lto2 run hybrid.o -save-temps -pass-remarks=. \
+; RUN:   -thinlto-threads=1 \
 ; RUN:   -o hybrid \
 ; RUN:   --whole-program-visibility-enabled-in-lto=true \
 ; RUN:   --validate-all-vtables-have-type-infos=true \
@@ -81,11 +84,11 @@
 ; RUN:   -r=hybrid.o,_ZN4Base8dispatchEv,px \
 ; RUN:   -r=hybrid.o,_ZN7DerivedC2Ev, \
 ; RUN:   -r=hybrid.o,_ZN8DerivedN5printEv,px \
-; RUN:   -r=hybrid.o,_ZTV8DerivedN,p \
-; RUN:   -r=hybrid.o,_ZTI8DerivedN,p \
+; RUN:   -r=hybrid.o,_ZTV8DerivedN, \
+; RUN:   -r=hybrid.o,_ZTI8DerivedN, \
 ; RUN:   -r=hybrid.o,_ZTS8DerivedN,p \
-; RUN:   -r=hybrid.o,_ZTI7Derived,d \
-; RUN:   -r=hybrid.o,_ZN8DerivedN5printEv,px \
+; RUN:   -r=hybrid.o,_ZTI7Derived, \
+; RUN:   -r=hybrid.o,_ZN8DerivedN5printEv, \
 ; RUN:   -r=hybrid.o,_ZTV8DerivedN,p \
 ; RUN:   -r=hybrid.o,_ZTI8DerivedN,p \
 ; RUN:   2>&1 | FileCheck --allow-empty %s --implicit-check-not='single-impl: devirtualized a call to'

llvm/tools/llvm-lto2/llvm-lto2.cpp

@@ -269,8 +269,6 @@ static int run(int argc, char **argv) {
         Res.VisibleToRegularObj = true;
       else if (C == 'r')
         Res.LinkerRedefined = true;
-      else if (C == 'd')
-        Res.ExportDynamic = true;
       else {
         llvm::errs() << "invalid character " << C << " in resolution: " << R
                      << '\n';