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[PM/AA] Reformat GlobalsModRef so that subsequent patches I make here

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don't continually introduce formatting deltas. NFC

llvm-svn: 242129
This commit is contained in:
Chandler Carruth 2015-07-14 08:42:39 +00:00
parent 2189465af9
commit 466d7ad42d
1 changed files with 168 additions and 163 deletions
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331
llvm/lib/Analysis/IPA/GlobalsModRef.cpp
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@ -42,94 +42,111 @@ STATISTIC(NumReadMemFunctions, "Number of functions that only read memory");
STATISTIC(NumIndirectGlobalVars, "Number of indirect global objects");
namespace {
/// FunctionRecord - One instance of this structure is stored for every
/// function in the program. Later, the entries for these functions are
/// removed if the function is found to call an external function (in which
/// case we know nothing about it.
struct FunctionRecord {
/// GlobalInfo - Maintain mod/ref info for all of the globals without
/// addresses taken that are read or written (transitively) by this
/// function.
std::map<const GlobalValue*, unsigned> GlobalInfo;
/// FunctionRecord - One instance of this structure is stored for every
/// function in the program. Later, the entries for these functions are
/// removed if the function is found to call an external function (in which
/// case we know nothing about it.
struct FunctionRecord {
/// GlobalInfo - Maintain mod/ref info for all of the globals without
/// addresses taken that are read or written (transitively) by this
/// function.
std::map<const GlobalValue *, unsigned> GlobalInfo;
/// MayReadAnyGlobal - May read global variables, but it is not known which.
bool MayReadAnyGlobal;
/// MayReadAnyGlobal - May read global variables, but it is not known which.
bool MayReadAnyGlobal;
unsigned getInfoForGlobal(const GlobalValue *GV) const {
unsigned Effect = MayReadAnyGlobal ? AliasAnalysis::Ref : 0;
std::map<const GlobalValue*, unsigned>::const_iterator I =
unsigned getInfoForGlobal(const GlobalValue *GV) const {
unsigned Effect = MayReadAnyGlobal ? AliasAnalysis::Ref : 0;
std::map<const GlobalValue *, unsigned>::const_iterator I =
GlobalInfo.find(GV);
if (I != GlobalInfo.end())
Effect |= I->second;
return Effect;
if (I != GlobalInfo.end())
Effect |= I->second;
return Effect;
}
/// FunctionEffect - Capture whether or not this function reads or writes to
/// ANY memory. If not, we can do a lot of aggressive analysis on it.
unsigned FunctionEffect;
FunctionRecord() : MayReadAnyGlobal(false), FunctionEffect(0) {}
};
/// GlobalsModRef - The actual analysis pass.
class GlobalsModRef : public ModulePass, public AliasAnalysis {
/// NonAddressTakenGlobals - The globals that do not have their addresses
/// taken.
std::set<const GlobalValue *> NonAddressTakenGlobals;
/// IndirectGlobals - The memory pointed to by this global is known to be
/// 'owned' by the global.
std::set<const GlobalValue *> IndirectGlobals;
/// AllocsForIndirectGlobals - If an instruction allocates memory for an
/// indirect global, this map indicates which one.
std::map<const Value *, const GlobalValue *> AllocsForIndirectGlobals;
/// FunctionInfo - For each function, keep track of what globals are
/// modified or read.
std::map<const Function *, FunctionRecord> FunctionInfo;
public:
static char ID;
GlobalsModRef() : ModulePass(ID) {
initializeGlobalsModRefPass(*PassRegistry::getPassRegistry());
}
bool runOnModule(Module &M) override {
InitializeAliasAnalysis(this, &M.getDataLayout());
// Find non-addr taken globals.
AnalyzeGlobals(M);
// Propagate on CG.
AnalyzeCallGraph(getAnalysis<CallGraphWrapperPass>().getCallGraph(), M);
return false;
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AliasAnalysis::getAnalysisUsage(AU);
AU.addRequired<CallGraphWrapperPass>();
AU.setPreservesAll(); // Does not transform code
}
//------------------------------------------------
// Implement the AliasAnalysis API
//
AliasResult alias(const MemoryLocation &LocA,
const MemoryLocation &LocB) override;
ModRefResult getModRefInfo(ImmutableCallSite CS,
const MemoryLocation &Loc) override;
ModRefResult getModRefInfo(ImmutableCallSite CS1,
ImmutableCallSite CS2) override {
return AliasAnalysis::getModRefInfo(CS1, CS2);
}
/// getModRefBehavior - Return the behavior of the specified function if
/// called from the specified call site. The call site may be null in which
/// case the most generic behavior of this function should be returned.
ModRefBehavior getModRefBehavior(const Function *F) override {
ModRefBehavior Min = UnknownModRefBehavior;
if (FunctionRecord *FR = getFunctionInfo(F)) {
if (FR->FunctionEffect == 0)
Min = DoesNotAccessMemory;
else if ((FR->FunctionEffect & Mod) == 0)
Min = OnlyReadsMemory;
}
/// FunctionEffect - Capture whether or not this function reads or writes to
/// ANY memory. If not, we can do a lot of aggressive analysis on it.
unsigned FunctionEffect;
return ModRefBehavior(AliasAnalysis::getModRefBehavior(F) & Min);
}
FunctionRecord() : MayReadAnyGlobal (false), FunctionEffect(0) {}
};
/// GlobalsModRef - The actual analysis pass.
class GlobalsModRef : public ModulePass, public AliasAnalysis {
/// NonAddressTakenGlobals - The globals that do not have their addresses
/// taken.
std::set<const GlobalValue*> NonAddressTakenGlobals;
/// IndirectGlobals - The memory pointed to by this global is known to be
/// 'owned' by the global.
std::set<const GlobalValue*> IndirectGlobals;
/// AllocsForIndirectGlobals - If an instruction allocates memory for an
/// indirect global, this map indicates which one.
std::map<const Value*, const GlobalValue*> AllocsForIndirectGlobals;
/// FunctionInfo - For each function, keep track of what globals are
/// modified or read.
std::map<const Function*, FunctionRecord> FunctionInfo;
public:
static char ID;
GlobalsModRef() : ModulePass(ID) {
initializeGlobalsModRefPass(*PassRegistry::getPassRegistry());
}
bool runOnModule(Module &M) override {
InitializeAliasAnalysis(this, &M.getDataLayout());
// Find non-addr taken globals.
AnalyzeGlobals(M);
// Propagate on CG.
AnalyzeCallGraph(getAnalysis<CallGraphWrapperPass>().getCallGraph(), M);
return false;
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AliasAnalysis::getAnalysisUsage(AU);
AU.addRequired<CallGraphWrapperPass>();
AU.setPreservesAll(); // Does not transform code
}
//------------------------------------------------
// Implement the AliasAnalysis API
//
AliasResult alias(const MemoryLocation &LocA,
const MemoryLocation &LocB) override;
ModRefResult getModRefInfo(ImmutableCallSite CS,
const MemoryLocation &Loc) override;
ModRefResult getModRefInfo(ImmutableCallSite CS1,
ImmutableCallSite CS2) override {
return AliasAnalysis::getModRefInfo(CS1, CS2);
}
/// getModRefBehavior - Return the behavior of the specified function if
/// called from the specified call site. The call site may be null in which
/// case the most generic behavior of this function should be returned.
ModRefBehavior getModRefBehavior(const Function *F) override {
ModRefBehavior Min = UnknownModRefBehavior;
/// getModRefBehavior - Return the behavior of the specified function if
/// called from the specified call site. The call site may be null in which
/// case the most generic behavior of this function should be returned.
ModRefBehavior getModRefBehavior(ImmutableCallSite CS) override {
ModRefBehavior Min = UnknownModRefBehavior;
if (const Function *F = CS.getCalledFunction())
if (FunctionRecord *FR = getFunctionInfo(F)) {
if (FR->FunctionEffect == 0)
Min = DoesNotAccessMemory;
@ -137,67 +154,50 @@ namespace {
Min = OnlyReadsMemory;
}
return ModRefBehavior(AliasAnalysis::getModRefBehavior(F) & Min);
}
/// getModRefBehavior - Return the behavior of the specified function if
/// called from the specified call site. The call site may be null in which
/// case the most generic behavior of this function should be returned.
ModRefBehavior getModRefBehavior(ImmutableCallSite CS) override {
ModRefBehavior Min = UnknownModRefBehavior;
return ModRefBehavior(AliasAnalysis::getModRefBehavior(CS) & Min);
}
if (const Function* F = CS.getCalledFunction())
if (FunctionRecord *FR = getFunctionInfo(F)) {
if (FR->FunctionEffect == 0)
Min = DoesNotAccessMemory;
else if ((FR->FunctionEffect & Mod) == 0)
Min = OnlyReadsMemory;
}
void deleteValue(Value *V) override;
void addEscapingUse(Use &U) override;
return ModRefBehavior(AliasAnalysis::getModRefBehavior(CS) & Min);
}
/// getAdjustedAnalysisPointer - This method is used when a pass implements
/// an analysis interface through multiple inheritance. If needed, it
/// should override this to adjust the this pointer as needed for the
/// specified pass info.
void *getAdjustedAnalysisPointer(AnalysisID PI) override {
if (PI == &AliasAnalysis::ID)
return (AliasAnalysis *)this;
return this;
}
void deleteValue(Value *V) override;
void addEscapingUse(Use &U) override;
/// getAdjustedAnalysisPointer - This method is used when a pass implements
/// an analysis interface through multiple inheritance. If needed, it
/// should override this to adjust the this pointer as needed for the
/// specified pass info.
void *getAdjustedAnalysisPointer(AnalysisID PI) override {
if (PI == &AliasAnalysis::ID)
return (AliasAnalysis*)this;
return this;
}
private:
/// getFunctionInfo - Return the function info for the function, or null if
/// we don't have anything useful to say about it.
FunctionRecord *getFunctionInfo(const Function *F) {
std::map<const Function*, FunctionRecord>::iterator I =
private:
/// getFunctionInfo - Return the function info for the function, or null if
/// we don't have anything useful to say about it.
FunctionRecord *getFunctionInfo(const Function *F) {
std::map<const Function *, FunctionRecord>::iterator I =
FunctionInfo.find(F);
if (I != FunctionInfo.end())
return &I->second;
return nullptr;
}
if (I != FunctionInfo.end())
return &I->second;
return nullptr;
}
void AnalyzeGlobals(Module &M);
void AnalyzeCallGraph(CallGraph &CG, Module &M);
bool AnalyzeUsesOfPointer(Value *V, std::vector<Function*> &Readers,
std::vector<Function*> &Writers,
GlobalValue *OkayStoreDest = nullptr);
bool AnalyzeIndirectGlobalMemory(GlobalValue *GV);
};
void AnalyzeGlobals(Module &M);
void AnalyzeCallGraph(CallGraph &CG, Module &M);
bool AnalyzeUsesOfPointer(Value *V, std::vector<Function *> &Readers,
std::vector<Function *> &Writers,
GlobalValue *OkayStoreDest = nullptr);
bool AnalyzeIndirectGlobalMemory(GlobalValue *GV);
};
}
char GlobalsModRef::ID = 0;
INITIALIZE_AG_PASS_BEGIN(GlobalsModRef, AliasAnalysis,
"globalsmodref-aa", "Simple mod/ref analysis for globals",
false, true, false)
INITIALIZE_AG_PASS_BEGIN(GlobalsModRef, AliasAnalysis, "globalsmodref-aa",
"Simple mod/ref analysis for globals", false, true,
false)
INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
INITIALIZE_AG_PASS_END(GlobalsModRef, AliasAnalysis,
"globalsmodref-aa", "Simple mod/ref analysis for globals",
false, true, false)
INITIALIZE_AG_PASS_END(GlobalsModRef, AliasAnalysis, "globalsmodref-aa",
"Simple mod/ref analysis for globals", false, true,
false)
Pass *llvm::createGlobalsModRefPass() { return new GlobalsModRef(); }
@ -206,7 +206,7 @@ Pass *llvm::createGlobalsModRefPass() { return new GlobalsModRef(); }
/// (really, their address passed to something nontrivial), record this fact,
/// and record the functions that they are used directly in.
void GlobalsModRef::AnalyzeGlobals(Module &M) {
std::vector<Function*> Readers, Writers;
std::vector<Function *> Readers, Writers;
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (I->hasLocalLinkage()) {
if (!AnalyzeUsesOfPointer(I, Readers, Writers)) {
@ -214,11 +214,12 @@ void GlobalsModRef::AnalyzeGlobals(Module &M) {
NonAddressTakenGlobals.insert(I);
++NumNonAddrTakenFunctions;
}
Readers.clear(); Writers.clear();
Readers.clear();
Writers.clear();
}
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
I != E; ++I)
for (Module::global_iterator I = M.global_begin(), E = M.global_end(); I != E;
++I)
if (I->hasLocalLinkage()) {
if (!AnalyzeUsesOfPointer(I, Readers, Writers)) {
// Remember that we are tracking this global, and the mod/ref fns
@ -227,7 +228,7 @@ void GlobalsModRef::AnalyzeGlobals(Module &M) {
for (unsigned i = 0, e = Readers.size(); i != e; ++i)
FunctionInfo[Readers[i]].GlobalInfo[I] |= Ref;
if (!I->isConstant()) // No need to keep track of writers to constants
if (!I->isConstant()) // No need to keep track of writers to constants
for (unsigned i = 0, e = Writers.size(); i != e; ++i)
FunctionInfo[Writers[i]].GlobalInfo[I] |= Mod;
++NumNonAddrTakenGlobalVars;
@ -237,7 +238,8 @@ void GlobalsModRef::AnalyzeGlobals(Module &M) {
AnalyzeIndirectGlobalMemory(I))
++NumIndirectGlobalVars;
}
Readers.clear(); Writers.clear();
Readers.clear();
Writers.clear();
}
}
@ -248,10 +250,11 @@ void GlobalsModRef::AnalyzeGlobals(Module &M) {
///
/// If OkayStoreDest is non-null, stores into this global are allowed.
bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V,
std::vector<Function*> &Readers,
std::vector<Function*> &Writers,
std::vector<Function *> &Readers,
std::vector<Function *> &Writers,
GlobalValue *OkayStoreDest) {
if (!V->getType()->isPointerTy()) return true;
if (!V->getType()->isPointerTy())
return true;
for (Use &U : V->uses()) {
User *I = U.getUser();
@ -261,7 +264,7 @@ bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V,
if (V == SI->getOperand(1)) {
Writers.push_back(SI->getParent()->getParent());
} else if (SI->getOperand(1) != OkayStoreDest) {
return true; // Storing the pointer
return true; // Storing the pointer
}
} else if (Operator::getOpcode(I) == Instruction::GetElementPtr) {
if (AnalyzeUsesOfPointer(I, Readers, Writers))
@ -281,7 +284,7 @@ bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V,
}
} else if (ICmpInst *ICI = dyn_cast<ICmpInst>(I)) {
if (!isa<ConstantPointerNull>(ICI->getOperand(1)))
return true; // Allow comparison against null.
return true; // Allow comparison against null.
} else {
return true;
}
@ -300,7 +303,7 @@ bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V,
bool GlobalsModRef::AnalyzeIndirectGlobalMemory(GlobalValue *GV) {
// Keep track of values related to the allocation of the memory, f.e. the
// value produced by the malloc call and any casts.
std::vector<Value*> AllocRelatedValues;
std::vector<Value *> AllocRelatedValues;
// Walk the user list of the global. If we find anything other than a direct
// load or store, bail out.
@ -309,13 +312,14 @@ bool GlobalsModRef::AnalyzeIndirectGlobalMemory(GlobalValue *GV) {
// The pointer loaded from the global can only be used in simple ways:
// we allow addressing of it and loading storing to it. We do *not* allow
// storing the loaded pointer somewhere else or passing to a function.
std::vector<Function*> ReadersWriters;
std::vector<Function *> ReadersWriters;
if (AnalyzeUsesOfPointer(LI, ReadersWriters, ReadersWriters))
return false; // Loaded pointer escapes.
return false; // Loaded pointer escapes.
// TODO: Could try some IP mod/ref of the loaded pointer.
} else if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
// Storing the global itself.
if (SI->getOperand(0) == GV) return false;
if (SI->getOperand(0) == GV)
return false;
// If storing the null pointer, ignore it.
if (isa<ConstantPointerNull>(SI->getOperand(0)))
@ -326,13 +330,13 @@ bool GlobalsModRef::AnalyzeIndirectGlobalMemory(GlobalValue *GV) {
GV->getParent()->getDataLayout());
if (!isAllocLikeFn(Ptr, TLI))
return false; // Too hard to analyze.
return false; // Too hard to analyze.
// Analyze all uses of the allocation. If any of them are used in a
// non-simple way (e.g. stored to another global) bail out.
std::vector<Function*> ReadersWriters;
std::vector<Function *> ReadersWriters;
if (AnalyzeUsesOfPointer(Ptr, ReadersWriters, ReadersWriters, GV))
return false; // Loaded pointer escapes.
return false; // Loaded pointer escapes.
// Remember that this allocation is related to the indirect global.
AllocRelatedValues.push_back(Ptr);
@ -359,7 +363,7 @@ bool GlobalsModRef::AnalyzeIndirectGlobalMemory(GlobalValue *GV) {
void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
// We do a bottom-up SCC traversal of the call graph. In other words, we
// visit all callees before callers (leaf-first).
for (scc_iterator<CallGraph*> I = scc_begin(&CG); !I.isAtEnd(); ++I) {
for (scc_iterator<CallGraph *> I = scc_begin(&CG); !I.isAtEnd(); ++I) {
const std::vector<CallGraphNode *> &SCC = *I;
assert(!SCC.empty() && "SCC with no functions?");
@ -436,9 +440,10 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
}
// Scan the function bodies for explicit loads or stores.
for (unsigned i = 0, e = SCC.size(); i != e && FunctionEffect != ModRef;++i)
for (unsigned i = 0, e = SCC.size(); i != e && FunctionEffect != ModRef;
++i)
for (inst_iterator II = inst_begin(SCC[i]->getFunction()),
E = inst_end(SCC[i]->getFunction());
E = inst_end(SCC[i]->getFunction());
II != E && FunctionEffect != ModRef; ++II)
if (LoadInst *LI = dyn_cast<LoadInst>(&*II)) {
FunctionEffect |= Ref;
@ -473,8 +478,6 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
}
}
/// alias - If one of the pointers is to a global that we are tracking, and the
/// other is some random pointer, we know there cannot be an alias, because the
/// address of the global isn't taken.
@ -491,8 +494,10 @@ AliasResult GlobalsModRef::alias(const MemoryLocation &LocA,
if (GV1 || GV2) {
// If the global's address is taken, pretend we don't know it's a pointer to
// the global.
if (GV1 && !NonAddressTakenGlobals.count(GV1)) GV1 = nullptr;
if (GV2 && !NonAddressTakenGlobals.count(GV2)) GV2 = nullptr;
if (GV1 && !NonAddressTakenGlobals.count(GV1))
GV1 = nullptr;
if (GV2 && !NonAddressTakenGlobals.count(GV2))
GV2 = nullptr;
// If the two pointers are derived from two different non-addr-taken
// globals, or if one is and the other isn't, we know these can't alias.
@ -553,7 +558,6 @@ GlobalsModRef::getModRefInfo(ImmutableCallSite CS, const MemoryLocation &Loc) {
return ModRefResult(Known & AliasAnalysis::getModRefInfo(CS, Loc));
}
//===----------------------------------------------------------------------===//
// Methods to update the analysis as a result of the client transformation.
//
@ -564,9 +568,10 @@ void GlobalsModRef::deleteValue(Value *V) {
// any AllocRelatedValues for it.
if (IndirectGlobals.erase(GV)) {
// Remove any entries in AllocsForIndirectGlobals for this global.
for (std::map<const Value*, const GlobalValue*>::iterator
I = AllocsForIndirectGlobals.begin(),
E = AllocsForIndirectGlobals.end(); I != E; ) {
for (std::map<const Value *, const GlobalValue *>::iterator
I = AllocsForIndirectGlobals.begin(),
E = AllocsForIndirectGlobals.end();
I != E;) {
if (I->second == GV) {
AllocsForIndirectGlobals.erase(I++);
} else {
@ -590,6 +595,6 @@ void GlobalsModRef::addEscapingUse(Use &U) {
// be more precise by processing the new use and attempting to update our
// saved analysis results to accommodate it.
deleteValue(U);
AliasAnalysis::addEscapingUse(U);
}