SchrodingerZhu updated this revision to Diff 441758.
SchrodingerZhu retitled this revision from "[llvm.analysis] Fix LTO for aliased
IFuncs.
As https://github.com/llvm/llvm-project/issues/56290 indicates,
when an ifunc is aliased in LTO, clang will attempt to create
an alias summary; however, as ifunc is not included in the
module summary..." to "[Analysis] Fix LTO for aliased IFuncs.".
SchrodingerZhu edited the summary of this revision.
SchrodingerZhu added a comment.
update code area
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D129009/new/
https://reviews.llvm.org/D129009
Files:
clang/test/Analysis/alias-indirect-function-lto.c
llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
Index: llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
===================================================================
--- llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -4103,8 +4103,10 @@
for (const GlobalAlias &A : M.aliases()) {
auto *Aliasee = A.getAliaseeObject();
- if (!Aliasee->hasName())
- // Nameless function don't have an entry in the summary, skip it.
+ if (!Aliasee->hasName() ||
+ Aliasee->getValueID() == Value::ValueTy::GlobalIFuncVal)
+ // IFunc function and Nameless function don't have an entry in the
+ // summary, skip it.
continue;
auto AliasId = VE.getValueID(&A);
auto AliaseeId = VE.getValueID(Aliasee);
Index: llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
===================================================================
--- llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -646,23 +646,26 @@
Index.addGlobalValueSummary(V, std::move(GVarSummary));
}
-static void
-computeAliasSummary(ModuleSummaryIndex &Index, const GlobalAlias &A,
- DenseSet<GlobalValue::GUID> &CantBePromoted) {
- bool NonRenamableLocal = isNonRenamableLocal(A);
- GlobalValueSummary::GVFlags Flags(
- A.getLinkage(), A.getVisibility(), NonRenamableLocal,
- /* Live = */ false, A.isDSOLocal(), A.canBeOmittedFromSymbolTable());
- auto AS = std::make_unique<AliasSummary>(Flags);
+static void computeAliasSummary(ModuleSummaryIndex &Index, const GlobalAlias
&A,
+ DenseSet<GlobalValue::GUID> &CantBePromoted) {
auto *Aliasee = A.getAliaseeObject();
- auto AliaseeVI = Index.getValueInfo(Aliasee->getGUID());
- assert(AliaseeVI && "Alias expects aliasee summary to be available");
- assert(AliaseeVI.getSummaryList().size() == 1 &&
- "Expected a single entry per aliasee in per-module index");
- AS->setAliasee(AliaseeVI, AliaseeVI.getSummaryList()[0].get());
- if (NonRenamableLocal)
- CantBePromoted.insert(A.getGUID());
- Index.addGlobalValueSummary(A, std::move(AS));
+ // Currently, skip summary for indirect function aliases as
+ // summary for aliasee will not be emitted.
+ if (Aliasee->getValueID() != Value::ValueTy::GlobalIFuncVal) {
+ bool NonRenamableLocal = isNonRenamableLocal(A);
+ GlobalValueSummary::GVFlags Flags(
+ A.getLinkage(), A.getVisibility(), NonRenamableLocal,
+ /* Live = */ false, A.isDSOLocal(), A.canBeOmittedFromSymbolTable());
+ auto AS = std::make_unique<AliasSummary>(Flags);
+ auto AliaseeVI = Index.getValueInfo(Aliasee->getGUID());
+ assert(AliaseeVI && "Alias expects aliasee summary to be available");
+ assert(AliaseeVI.getSummaryList().size() == 1 &&
+ "Expected a single entry per aliasee in per-module index");
+ AS->setAliasee(AliaseeVI, AliaseeVI.getSummaryList()[0].get());
+ if (NonRenamableLocal)
+ CantBePromoted.insert(A.getGUID());
+ Index.addGlobalValueSummary(A, std::move(AS));
+ }
}
// Set LiveRoot flag on entries matching the given value name.
Index: clang/test/Analysis/alias-indirect-function-lto.c
===================================================================
--- /dev/null
+++ clang/test/Analysis/alias-indirect-function-lto.c
@@ -0,0 +1,4 @@
+// RUN: %clang_analyze_cc1 -flto -c
+void f() __attribute__((ifunc("g")));
+static void *g() { return 0; };
+void h() __attribute__((alias("f")));
\ No newline at end of file
Index: llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
===================================================================
--- llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -4103,8 +4103,10 @@
for (const GlobalAlias &A : M.aliases()) {
auto *Aliasee = A.getAliaseeObject();
- if (!Aliasee->hasName())
- // Nameless function don't have an entry in the summary, skip it.
+ if (!Aliasee->hasName() ||
+ Aliasee->getValueID() == Value::ValueTy::GlobalIFuncVal)
+ // IFunc function and Nameless function don't have an entry in the
+ // summary, skip it.
continue;
auto AliasId = VE.getValueID(&A);
auto AliaseeId = VE.getValueID(Aliasee);
Index: llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
===================================================================
--- llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -646,23 +646,26 @@
Index.addGlobalValueSummary(V, std::move(GVarSummary));
}
-static void
-computeAliasSummary(ModuleSummaryIndex &Index, const GlobalAlias &A,
- DenseSet<GlobalValue::GUID> &CantBePromoted) {
- bool NonRenamableLocal = isNonRenamableLocal(A);
- GlobalValueSummary::GVFlags Flags(
- A.getLinkage(), A.getVisibility(), NonRenamableLocal,
- /* Live = */ false, A.isDSOLocal(), A.canBeOmittedFromSymbolTable());
- auto AS = std::make_unique<AliasSummary>(Flags);
+static void computeAliasSummary(ModuleSummaryIndex &Index, const GlobalAlias &A,
+ DenseSet<GlobalValue::GUID> &CantBePromoted) {
auto *Aliasee = A.getAliaseeObject();
- auto AliaseeVI = Index.getValueInfo(Aliasee->getGUID());
- assert(AliaseeVI && "Alias expects aliasee summary to be available");
- assert(AliaseeVI.getSummaryList().size() == 1 &&
- "Expected a single entry per aliasee in per-module index");
- AS->setAliasee(AliaseeVI, AliaseeVI.getSummaryList()[0].get());
- if (NonRenamableLocal)
- CantBePromoted.insert(A.getGUID());
- Index.addGlobalValueSummary(A, std::move(AS));
+ // Currently, skip summary for indirect function aliases as
+ // summary for aliasee will not be emitted.
+ if (Aliasee->getValueID() != Value::ValueTy::GlobalIFuncVal) {
+ bool NonRenamableLocal = isNonRenamableLocal(A);
+ GlobalValueSummary::GVFlags Flags(
+ A.getLinkage(), A.getVisibility(), NonRenamableLocal,
+ /* Live = */ false, A.isDSOLocal(), A.canBeOmittedFromSymbolTable());
+ auto AS = std::make_unique<AliasSummary>(Flags);
+ auto AliaseeVI = Index.getValueInfo(Aliasee->getGUID());
+ assert(AliaseeVI && "Alias expects aliasee summary to be available");
+ assert(AliaseeVI.getSummaryList().size() == 1 &&
+ "Expected a single entry per aliasee in per-module index");
+ AS->setAliasee(AliaseeVI, AliaseeVI.getSummaryList()[0].get());
+ if (NonRenamableLocal)
+ CantBePromoted.insert(A.getGUID());
+ Index.addGlobalValueSummary(A, std::move(AS));
+ }
}
// Set LiveRoot flag on entries matching the given value name.
Index: clang/test/Analysis/alias-indirect-function-lto.c
===================================================================
--- /dev/null
+++ clang/test/Analysis/alias-indirect-function-lto.c
@@ -0,0 +1,4 @@
+// RUN: %clang_analyze_cc1 -flto -c
+void f() __attribute__((ifunc("g")));
+static void *g() { return 0; };
+void h() __attribute__((alias("f")));
\ No newline at end of file
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