[llvm] r268468 - [GlobalDCE, Misc] Don't remove functions referenced by ifuncs
David Majnemer via llvm-commits
llvm-commits at lists.llvm.org
Tue May 3 17:20:49 PDT 2016
Author: majnemer
Date: Tue May 3 19:20:48 2016
New Revision: 268468
URL: http://llvm.org/viewvc/llvm-project?rev=268468&view=rev
Log:
[GlobalDCE, Misc] Don't remove functions referenced by ifuncs
We forgot to consider the target of ifuncs when considering if a
function was alive or dead.
N.B. Also update a few auxiliary tools like bugpoint and
verify-uselistorder.
This fixes PR27593.
Added:
llvm/trunk/test/Transforms/GlobalDCE/global-ifunc.ll
Modified:
llvm/trunk/include/llvm/IR/GlobalAlias.h
llvm/trunk/include/llvm/IR/GlobalIndirectSymbol.h
llvm/trunk/lib/Transforms/IPO/GlobalDCE.cpp
llvm/trunk/lib/Transforms/Utils/SplitModule.cpp
llvm/trunk/tools/bugpoint/CrashDebugger.cpp
llvm/trunk/tools/verify-uselistorder/verify-uselistorder.cpp
Modified: llvm/trunk/include/llvm/IR/GlobalAlias.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/GlobalAlias.h?rev=268468&r1=268467&r2=268468&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/GlobalAlias.h (original)
+++ llvm/trunk/include/llvm/IR/GlobalAlias.h Tue May 3 19:20:48 2016
@@ -78,21 +78,6 @@ public:
return getIndirectSymbol();
}
- const GlobalObject *getBaseObject() const {
- return const_cast<GlobalAlias *>(this)->getBaseObject();
- }
- GlobalObject *getBaseObject() {
- return dyn_cast<GlobalObject>(getAliasee()->stripInBoundsOffsets());
- }
-
- const GlobalObject *getBaseObject(const DataLayout &DL, APInt &Offset) const {
- return const_cast<GlobalAlias *>(this)->getBaseObject(DL, Offset);
- }
- GlobalObject *getBaseObject(const DataLayout &DL, APInt &Offset) {
- return dyn_cast<GlobalObject>(
- getAliasee()->stripAndAccumulateInBoundsConstantOffsets(DL, Offset));
- }
-
static bool isValidLinkage(LinkageTypes L) {
return isExternalLinkage(L) || isLocalLinkage(L) ||
isWeakLinkage(L) || isLinkOnceLinkage(L);
Modified: llvm/trunk/include/llvm/IR/GlobalIndirectSymbol.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/GlobalIndirectSymbol.h?rev=268468&r1=268467&r2=268468&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/GlobalIndirectSymbol.h (original)
+++ llvm/trunk/include/llvm/IR/GlobalIndirectSymbol.h Tue May 3 19:20:48 2016
@@ -49,6 +49,22 @@ public:
return getOperand(0);
}
+ const GlobalObject *getBaseObject() const {
+ return const_cast<GlobalIndirectSymbol *>(this)->getBaseObject();
+ }
+ GlobalObject *getBaseObject() {
+ return dyn_cast<GlobalObject>(getIndirectSymbol()->stripInBoundsOffsets());
+ }
+
+ const GlobalObject *getBaseObject(const DataLayout &DL, APInt &Offset) const {
+ return const_cast<GlobalIndirectSymbol *>(this)->getBaseObject(DL, Offset);
+ }
+ GlobalObject *getBaseObject(const DataLayout &DL, APInt &Offset) {
+ return dyn_cast<GlobalObject>(
+ getIndirectSymbol()->stripAndAccumulateInBoundsConstantOffsets(DL,
+ Offset));
+ }
+
// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const Value *V) {
return V->getValueID() == Value::GlobalAliasVal ||
Modified: llvm/trunk/lib/Transforms/IPO/GlobalDCE.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/GlobalDCE.cpp?rev=268468&r1=268467&r2=268468&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/GlobalDCE.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/GlobalDCE.cpp Tue May 3 19:20:48 2016
@@ -32,6 +32,7 @@ using namespace llvm;
STATISTIC(NumAliases , "Number of global aliases removed");
STATISTIC(NumFunctions, "Number of functions removed");
+STATISTIC(NumIFuncs, "Number of indirect functions removed");
STATISTIC(NumVariables, "Number of global variables removed");
namespace {
@@ -118,6 +119,13 @@ PreservedAnalyses GlobalDCEPass::run(Mod
GlobalIsNeeded(&GA);
}
+ for (GlobalIFunc &GIF : M.ifuncs()) {
+ Changed |= RemoveUnusedGlobalValue(GIF);
+ // Externally visible ifuncs are needed.
+ if (!GIF.isDiscardableIfUnused())
+ GlobalIsNeeded(&GIF);
+ }
+
// Now that all globals which are needed are in the AliveGlobals set, we loop
// through the program, deleting those which are not alive.
//
@@ -152,6 +160,14 @@ PreservedAnalyses GlobalDCEPass::run(Mod
GA.setAliasee(nullptr);
}
+ // The third pass drops targets of ifuncs which are dead...
+ std::vector<GlobalIFunc*> DeadIFuncs;
+ for (GlobalIFunc &GIF : M.ifuncs())
+ if (!AliveGlobals.count(&GIF)) {
+ DeadIFuncs.push_back(&GIF);
+ GIF.setResolver(nullptr);
+ }
+
if (!DeadFunctions.empty()) {
// Now that all interferences have been dropped, delete the actual objects
// themselves.
@@ -182,6 +198,16 @@ PreservedAnalyses GlobalDCEPass::run(Mod
Changed = true;
}
+ // Now delete any dead aliases.
+ if (!DeadIFuncs.empty()) {
+ for (GlobalIFunc *GIF : DeadIFuncs) {
+ RemoveUnusedGlobalValue(*GIF);
+ M.getIFuncList().erase(GIF);
+ }
+ NumIFuncs += DeadIFuncs.size();
+ Changed = true;
+ }
+
// Make sure that all memory is released
AliveGlobals.clear();
SeenConstants.clear();
Modified: llvm/trunk/lib/Transforms/Utils/SplitModule.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SplitModule.cpp?rev=268468&r1=268467&r2=268468&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SplitModule.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SplitModule.cpp Tue May 3 19:20:48 2016
@@ -47,7 +47,7 @@ static void addNonConstUser(ClusterMapTy
if (const Instruction *I = dyn_cast<Instruction>(U)) {
const GlobalValue *F = I->getParent()->getParent();
GVtoClusterMap.unionSets(GV, F);
- } else if (isa<GlobalAlias>(U) || isa<Function>(U) ||
+ } else if (isa<GlobalIndirectSymbol>(U) || isa<Function>(U) ||
isa<GlobalVariable>(U)) {
GVtoClusterMap.unionSets(GV, cast<GlobalValue>(U));
} else {
@@ -107,8 +107,8 @@ static void findPartitions(Module *M, Cl
// For aliases we should not separate them from their aliasees regardless
// of linkage.
- if (GlobalAlias *GA = dyn_cast<GlobalAlias>(&GV)) {
- if (const GlobalObject *Base = GA->getBaseObject())
+ if (auto *GIS = dyn_cast<GlobalIndirectSymbol>(&GV)) {
+ if (const GlobalObject *Base = GIS->getBaseObject())
GVtoClusterMap.unionSets(&GV, Base);
}
@@ -205,8 +205,8 @@ static void externalize(GlobalValue *GV)
// Returns whether GV should be in partition (0-based) I of N.
static bool isInPartition(const GlobalValue *GV, unsigned I, unsigned N) {
- if (auto GA = dyn_cast<GlobalAlias>(GV))
- if (const GlobalObject *Base = GA->getBaseObject())
+ if (auto *GIS = dyn_cast<GlobalIndirectSymbol>(GV))
+ if (const GlobalObject *Base = GIS->getBaseObject())
GV = Base;
StringRef Name;
@@ -236,6 +236,8 @@ void llvm::SplitModule(
externalize(&GV);
for (GlobalAlias &GA : M->aliases())
externalize(&GA);
+ for (GlobalIFunc &GIF : M->ifuncs())
+ externalize(&GIF);
}
// This performs splitting without a need for externalization, which might not
Added: llvm/trunk/test/Transforms/GlobalDCE/global-ifunc.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GlobalDCE/global-ifunc.ll?rev=268468&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GlobalDCE/global-ifunc.ll (added)
+++ llvm/trunk/test/Transforms/GlobalDCE/global-ifunc.ll Tue May 3 19:20:48 2016
@@ -0,0 +1,13 @@
+; RUN: opt -S -globaldce < %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at if = ifunc void (), void ()* @fn
+
+define internal void @fn() {
+entry:
+ ret void
+}
+
+; CHECK-DAG: @if = ifunc void (), void ()* @fn
+; CHECK-DAG: define internal void @fn(
Modified: llvm/trunk/tools/bugpoint/CrashDebugger.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/bugpoint/CrashDebugger.cpp?rev=268468&r1=268467&r2=268468&view=diff
==============================================================================
--- llvm/trunk/tools/bugpoint/CrashDebugger.cpp (original)
+++ llvm/trunk/tools/bugpoint/CrashDebugger.cpp Tue May 3 19:20:48 2016
@@ -264,8 +264,8 @@ bool ReduceCrashingFunctions::TestFuncs(
std::vector<GlobalValue*> ToRemove;
// First, remove aliases to functions we're about to purge.
for (GlobalAlias &Alias : M->aliases()) {
- Constant *Root = Alias.getAliasee()->stripPointerCasts();
- Function *F = dyn_cast<Function>(Root);
+ GlobalObject *Root = Alias.getBaseObject();
+ Function *F = dyn_cast_or_null<Function>(Root);
if (F) {
if (Functions.count(F))
// We're keeping this function.
Modified: llvm/trunk/tools/verify-uselistorder/verify-uselistorder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/verify-uselistorder/verify-uselistorder.cpp?rev=268468&r1=268467&r2=268468&view=diff
==============================================================================
--- llvm/trunk/tools/verify-uselistorder/verify-uselistorder.cpp (original)
+++ llvm/trunk/tools/verify-uselistorder/verify-uselistorder.cpp Tue May 3 19:20:48 2016
@@ -191,6 +191,8 @@ ValueMapping::ValueMapping(const Module
map(&G);
for (const GlobalAlias &A : M.aliases())
map(&A);
+ for (const GlobalIFunc &IF : M.ifuncs())
+ map(&IF);
for (const Function &F : M)
map(&F);
@@ -200,6 +202,8 @@ ValueMapping::ValueMapping(const Module
map(G.getInitializer());
for (const GlobalAlias &A : M.aliases())
map(A.getAliasee());
+ for (const GlobalIFunc &IF : M.ifuncs())
+ map(IF.getResolver());
for (const Function &F : M) {
if (F.hasPrefixData())
map(F.getPrefixData());
@@ -463,6 +467,8 @@ static void changeUseLists(Module &M, Ch
changeValueUseList(&G);
for (GlobalAlias &A : M.aliases())
changeValueUseList(&A);
+ for (GlobalIFunc &IF : M.ifuncs())
+ changeValueUseList(&IF);
for (Function &F : M)
changeValueUseList(&F);
@@ -472,6 +478,8 @@ static void changeUseLists(Module &M, Ch
changeValueUseList(G.getInitializer());
for (GlobalAlias &A : M.aliases())
changeValueUseList(A.getAliasee());
+ for (GlobalIFunc &IF : M.ifuncs())
+ changeValueUseList(IF.getResolver());
for (Function &F : M) {
if (F.hasPrefixData())
changeValueUseList(F.getPrefixData());
More information about the llvm-commits
mailing list