[llvm] 28a06a1 - [NFC][FuncAttrs] Keep track of modified functions
Arthur Eubanks via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 8 15:05:13 PST 2021
Author: Arthur Eubanks
Date: 2021-11-08T15:04:56-08:00
New Revision: 28a06a1b8795604403c5ac2fdd69e676050c27a2
URL: https://github.com/llvm/llvm-project/commit/28a06a1b8795604403c5ac2fdd69e676050c27a2
DIFF: https://github.com/llvm/llvm-project/commit/28a06a1b8795604403c5ac2fdd69e676050c27a2.diff
LOG: [NFC][FuncAttrs] Keep track of modified functions
This is in preparation for only invalidating analyses on changed
functions.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D113303
Added:
Modified:
llvm/lib/Transforms/IPO/FunctionAttrs.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index 935375e89393c..2ad7403d3ad30 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -19,6 +19,7 @@
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AssumptionCache.h"
@@ -249,7 +250,8 @@ MemoryAccessKind llvm::computeFunctionBodyMemoryAccess(Function &F,
/// Deduce readonly/readnone attributes for the SCC.
template <typename AARGetterT>
-static bool addReadAttrs(const SCCNodeSet &SCCNodes, AARGetterT &&AARGetter) {
+static void addReadAttrs(const SCCNodeSet &SCCNodes, AARGetterT &&AARGetter,
+ SmallSet<Function *, 8> &Changed) {
// Check if any of the functions in the SCC read or write memory. If they
// write memory then they can't be marked readnone or readonly.
bool ReadsMemory = false;
@@ -264,7 +266,7 @@ static bool addReadAttrs(const SCCNodeSet &SCCNodes, AARGetterT &&AARGetter) {
switch (checkFunctionMemoryAccess(*F, F->hasExactDefinition(),
AAR, SCCNodes)) {
case MAK_MayWrite:
- return false;
+ return;
case MAK_ReadOnly:
ReadsMemory = true;
break;
@@ -280,11 +282,10 @@ static bool addReadAttrs(const SCCNodeSet &SCCNodes, AARGetterT &&AARGetter) {
// If the SCC contains both functions that read and functions that write, then
// we cannot add readonly attributes.
if (ReadsMemory && WritesMemory)
- return false;
+ return;
// Success! Functions in this SCC do not access memory, or only read memory.
// Give them the appropriate attribute.
- bool MadeChange = false;
for (Function *F : SCCNodes) {
if (F->doesNotAccessMemory())
@@ -298,7 +299,7 @@ static bool addReadAttrs(const SCCNodeSet &SCCNodes, AARGetterT &&AARGetter) {
if (F->doesNotReadMemory() && WritesMemory)
continue;
- MadeChange = true;
+ Changed.insert(F);
// Clear out any existing attributes.
AttrBuilder AttrsToRemove;
@@ -327,8 +328,6 @@ static bool addReadAttrs(const SCCNodeSet &SCCNodes, AARGetterT &&AARGetter) {
else
++NumReadNone;
}
-
- return MadeChange;
}
// Compute definitive function attributes for a function taking into account
@@ -779,9 +778,8 @@ determinePointerReadAttrs(Argument *A,
}
/// Deduce returned attributes for the SCC.
-static bool addArgumentReturnedAttrs(const SCCNodeSet &SCCNodes) {
- bool Changed = false;
-
+static void addArgumentReturnedAttrs(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
// Check each function in turn, determining if an argument is always returned.
for (Function *F : SCCNodes) {
// We can infer and propagate function attributes only when we know that the
@@ -821,11 +819,9 @@ static bool addArgumentReturnedAttrs(const SCCNodeSet &SCCNodes) {
auto *A = cast<Argument>(RetArg);
A->addAttr(Attribute::Returned);
++NumReturned;
- Changed = true;
+ Changed.insert(F);
}
}
-
- return Changed;
}
/// If a callsite has arguments that are also arguments to the parent function,
@@ -891,9 +887,8 @@ static bool addReadAttr(Argument *A, Attribute::AttrKind R) {
}
/// Deduce nocapture attributes for the SCC.
-static bool addArgumentAttrs(const SCCNodeSet &SCCNodes) {
- bool Changed = false;
-
+static void addArgumentAttrs(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
ArgumentGraph AG;
// Check each function in turn, determining which pointer arguments are not
@@ -905,7 +900,8 @@ static bool addArgumentAttrs(const SCCNodeSet &SCCNodes) {
if (!F->hasExactDefinition())
continue;
- Changed |= addArgumentAttrsFromCallsites(*F);
+ if (addArgumentAttrsFromCallsites(*F))
+ Changed.insert(F);
// Functions that are readonly (or readnone) and nounwind and don't return
// a value can't capture arguments. Don't analyze them.
@@ -916,7 +912,7 @@ static bool addArgumentAttrs(const SCCNodeSet &SCCNodes) {
if (A->getType()->isPointerTy() && !A->hasNoCaptureAttr()) {
A->addAttr(Attribute::NoCapture);
++NumNoCapture;
- Changed = true;
+ Changed.insert(F);
}
}
continue;
@@ -935,7 +931,7 @@ static bool addArgumentAttrs(const SCCNodeSet &SCCNodes) {
// If it's trivially not captured, mark it nocapture now.
A->addAttr(Attribute::NoCapture);
++NumNoCapture;
- Changed = true;
+ Changed.insert(F);
} else {
// If it's not trivially captured and not trivially not captured,
// then it must be calling into another function in our SCC. Save
@@ -959,7 +955,8 @@ static bool addArgumentAttrs(const SCCNodeSet &SCCNodes) {
Self.insert(&*A);
Attribute::AttrKind R = determinePointerReadAttrs(&*A, Self);
if (R != Attribute::None)
- Changed = addReadAttr(A, R);
+ if (addReadAttr(A, R))
+ Changed.insert(F);
}
}
}
@@ -983,7 +980,7 @@ static bool addArgumentAttrs(const SCCNodeSet &SCCNodes) {
Argument *A = ArgumentSCC[0]->Definition;
A->addAttr(Attribute::NoCapture);
++NumNoCapture;
- Changed = true;
+ Changed.insert(A->getParent());
}
continue;
}
@@ -1025,7 +1022,7 @@ static bool addArgumentAttrs(const SCCNodeSet &SCCNodes) {
Argument *A = ArgumentSCC[i]->Definition;
A->addAttr(Attribute::NoCapture);
++NumNoCapture;
- Changed = true;
+ Changed.insert(A->getParent());
}
// We also want to compute readonly/readnone. With a small number of false
@@ -1056,12 +1053,11 @@ static bool addArgumentAttrs(const SCCNodeSet &SCCNodes) {
if (ReadAttr != Attribute::None) {
for (unsigned i = 0, e = ArgumentSCC.size(); i != e; ++i) {
Argument *A = ArgumentSCC[i]->Definition;
- Changed = addReadAttr(A, ReadAttr);
+ if (addReadAttr(A, ReadAttr))
+ Changed.insert(A->getParent());
}
}
}
-
- return Changed;
}
/// Tests whether a function is "malloc-like".
@@ -1132,7 +1128,8 @@ static bool isFunctionMallocLike(Function *F, const SCCNodeSet &SCCNodes) {
}
/// Deduce noalias attributes for the SCC.
-static bool addNoAliasAttrs(const SCCNodeSet &SCCNodes) {
+static void addNoAliasAttrs(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
// Check each function in turn, determining which functions return noalias
// pointers.
for (Function *F : SCCNodes) {
@@ -1144,7 +1141,7 @@ static bool addNoAliasAttrs(const SCCNodeSet &SCCNodes) {
// definition we'll get at link time is *exactly* the definition we see now.
// For more details, see GlobalValue::mayBeDerefined.
if (!F->hasExactDefinition())
- return false;
+ return;
// We annotate noalias return values, which are only applicable to
// pointer types.
@@ -1152,10 +1149,9 @@ static bool addNoAliasAttrs(const SCCNodeSet &SCCNodes) {
continue;
if (!isFunctionMallocLike(F, SCCNodes))
- return false;
+ return;
}
- bool MadeChange = false;
for (Function *F : SCCNodes) {
if (F->returnDoesNotAlias() ||
!F->getReturnType()->isPointerTy())
@@ -1163,10 +1159,8 @@ static bool addNoAliasAttrs(const SCCNodeSet &SCCNodes) {
F->setReturnDoesNotAlias();
++NumNoAlias;
- MadeChange = true;
+ Changed.insert(F);
}
-
- return MadeChange;
}
/// Tests whether this function is known to not return null.
@@ -1242,13 +1236,12 @@ static bool isReturnNonNull(Function *F, const SCCNodeSet &SCCNodes,
}
/// Deduce nonnull attributes for the SCC.
-static bool addNonNullAttrs(const SCCNodeSet &SCCNodes) {
+static void addNonNullAttrs(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
// Speculative that all functions in the SCC return only nonnull
// pointers. We may refute this as we analyze functions.
bool SCCReturnsNonNull = true;
- bool MadeChange = false;
-
// Check each function in turn, determining which functions return nonnull
// pointers.
for (Function *F : SCCNodes) {
@@ -1260,7 +1253,7 @@ static bool addNonNullAttrs(const SCCNodeSet &SCCNodes) {
// definition we'll get at link time is *exactly* the definition we see now.
// For more details, see GlobalValue::mayBeDerefined.
if (!F->hasExactDefinition())
- return false;
+ return;
// We annotate nonnull return values, which are only applicable to
// pointer types.
@@ -1276,7 +1269,7 @@ static bool addNonNullAttrs(const SCCNodeSet &SCCNodes) {
<< " as nonnull\n");
F->addRetAttr(Attribute::NonNull);
++NumNonNullReturn;
- MadeChange = true;
+ Changed.insert(F);
}
continue;
}
@@ -1294,11 +1287,9 @@ static bool addNonNullAttrs(const SCCNodeSet &SCCNodes) {
LLVM_DEBUG(dbgs() << "SCC marking " << F->getName() << " as nonnull\n");
F->addRetAttr(Attribute::NonNull);
++NumNonNullReturn;
- MadeChange = true;
+ Changed.insert(F);
}
}
-
- return MadeChange;
}
namespace {
@@ -1351,12 +1342,13 @@ class AttributeInferer {
InferenceDescriptors.push_back(AttrInference);
}
- bool run(const SCCNodeSet &SCCNodes);
+ void run(const SCCNodeSet &SCCNodes, SmallSet<Function *, 8> &Changed);
};
/// Perform all the requested attribute inference actions according to the
/// attribute predicates stored before.
-bool AttributeInferer::run(const SCCNodeSet &SCCNodes) {
+void AttributeInferer::run(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
SmallVector<InferenceDescriptor, 4> InferInSCC = InferenceDescriptors;
// Go through all the functions in SCC and check corresponding attribute
// assumptions for each of them. Attributes that are invalid for this SCC
@@ -1365,7 +1357,7 @@ bool AttributeInferer::run(const SCCNodeSet &SCCNodes) {
// No attributes whose assumptions are still valid - done.
if (InferInSCC.empty())
- return false;
+ return;
// Check if our attributes ever need scanning/can be scanned.
llvm::erase_if(InferInSCC, [F](const InferenceDescriptor &ID) {
@@ -1408,9 +1400,8 @@ bool AttributeInferer::run(const SCCNodeSet &SCCNodes) {
}
if (InferInSCC.empty())
- return false;
+ return;
- bool Changed = false;
for (Function *F : SCCNodes)
// At this point InferInSCC contains only functions that were either:
// - explicitly skipped from scan/inference, or
@@ -1419,10 +1410,9 @@ bool AttributeInferer::run(const SCCNodeSet &SCCNodes) {
for (auto &ID : InferInSCC) {
if (ID.SkipFunction(*F))
continue;
- Changed = true;
+ Changed.insert(F);
ID.SetAttribute(*F);
}
- return Changed;
}
struct SCCNodesResult {
@@ -1478,7 +1468,8 @@ static bool InstrBreaksNoFree(Instruction &I, const SCCNodeSet &SCCNodes) {
/// Attempt to remove convergent function attribute when possible.
///
/// Returns true if any changes to function attributes were made.
-static bool inferConvergent(const SCCNodeSet &SCCNodes) {
+static void inferConvergent(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
AttributeInferer AI;
// Request to remove the convergent attribute from all functions in the SCC
@@ -1501,7 +1492,7 @@ static bool inferConvergent(const SCCNodeSet &SCCNodes) {
},
/* RequiresExactDefinition= */ false});
// Perform all the requested attribute inference actions.
- return AI.run(SCCNodes);
+ AI.run(SCCNodes, Changed);
}
/// Infer attributes from all functions in the SCC by scanning every
@@ -1510,7 +1501,8 @@ static bool inferConvergent(const SCCNodeSet &SCCNodes) {
/// - addition of NoUnwind attribute
///
/// Returns true if any changes to function attributes were made.
-static bool inferAttrsFromFunctionBodies(const SCCNodeSet &SCCNodes) {
+static void inferAttrsFromFunctionBodies(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
AttributeInferer AI;
if (!DisableNoUnwindInference)
@@ -1559,19 +1551,20 @@ static bool inferAttrsFromFunctionBodies(const SCCNodeSet &SCCNodes) {
/* RequiresExactDefinition= */ true});
// Perform all the requested attribute inference actions.
- return AI.run(SCCNodes);
+ AI.run(SCCNodes, Changed);
}
-static bool addNoRecurseAttrs(const SCCNodeSet &SCCNodes) {
+static void addNoRecurseAttrs(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
// Try and identify functions that do not recurse.
// If the SCC contains multiple nodes we know for sure there is recursion.
if (SCCNodes.size() != 1)
- return false;
+ return;
Function *F = *SCCNodes.begin();
if (!F || !F->hasExactDefinition() || F->doesNotRecurse())
- return false;
+ return;
// If all of the calls in F are identifiable and are to norecurse functions, F
// is norecurse. This check also detects self-recursion as F is not currently
@@ -1582,7 +1575,7 @@ static bool addNoRecurseAttrs(const SCCNodeSet &SCCNodes) {
Function *Callee = CB->getCalledFunction();
if (!Callee || Callee == F || !Callee->doesNotRecurse())
// Function calls a potentially recursive function.
- return false;
+ return;
}
// Every call was to a non-recursive function other than this function, and
@@ -1590,7 +1583,7 @@ static bool addNoRecurseAttrs(const SCCNodeSet &SCCNodes) {
// recurse.
F->setDoesNotRecurse();
++NumNoRecurse;
- return true;
+ Changed.insert(F);
}
static bool instructionDoesNotReturn(Instruction &I) {
@@ -1608,9 +1601,8 @@ static bool basicBlockCanReturn(BasicBlock &BB) {
}
// Set the noreturn function attribute if possible.
-static bool addNoReturnAttrs(const SCCNodeSet &SCCNodes) {
- bool Changed = false;
-
+static void addNoReturnAttrs(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
for (Function *F : SCCNodes) {
if (!F || !F->hasExactDefinition() || F->hasFnAttribute(Attribute::Naked) ||
F->doesNotReturn())
@@ -1620,11 +1612,9 @@ static bool addNoReturnAttrs(const SCCNodeSet &SCCNodes) {
// FIXME: this doesn't handle recursion or unreachable blocks.
if (none_of(*F, basicBlockCanReturn)) {
F->setDoesNotReturn();
- Changed = true;
+ Changed.insert(F);
}
}
-
- return Changed;
}
static bool functionWillReturn(const Function &F) {
@@ -1657,19 +1647,16 @@ static bool functionWillReturn(const Function &F) {
}
// Set the willreturn function attribute if possible.
-static bool addWillReturn(const SCCNodeSet &SCCNodes) {
- bool Changed = false;
-
+static void addWillReturn(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
for (Function *F : SCCNodes) {
if (!F || F->willReturn() || !functionWillReturn(*F))
continue;
F->setWillReturn();
NumWillReturn++;
- Changed = true;
+ Changed.insert(F);
}
-
- return Changed;
}
// Return true if this is an atomic which has an ordering stronger than
@@ -1728,7 +1715,8 @@ static bool InstrBreaksNoSync(Instruction &I, const SCCNodeSet &SCCNodes) {
}
// Infer the nosync attribute.
-static bool addNoSyncAttr(const SCCNodeSet &SCCNodes) {
+static void addNoSyncAttr(const SCCNodeSet &SCCNodes,
+ SmallSet<Function *, 8> &Changed) {
AttributeInferer AI;
AI.registerAttrInference(AttributeInferer::InferenceDescriptor{
Attribute::NoSync,
@@ -1745,7 +1733,7 @@ static bool addNoSyncAttr(const SCCNodeSet &SCCNodes) {
++NumNoSync;
},
/* RequiresExactDefinition= */ true});
- return AI.run(SCCNodes);
+ AI.run(SCCNodes, Changed);
}
static SCCNodesResult createSCCNodeSet(ArrayRef<Function *> Functions) {
@@ -1779,32 +1767,33 @@ static SCCNodesResult createSCCNodeSet(ArrayRef<Function *> Functions) {
}
template <typename AARGetterT>
-static bool deriveAttrsInPostOrder(ArrayRef<Function *> Functions,
- AARGetterT &&AARGetter) {
+static SmallSet<Function *, 8>
+deriveAttrsInPostOrder(ArrayRef<Function *> Functions, AARGetterT &&AARGetter) {
SCCNodesResult Nodes = createSCCNodeSet(Functions);
- bool Changed = false;
// Bail if the SCC only contains optnone functions.
if (Nodes.SCCNodes.empty())
- return Changed;
+ return {};
- Changed |= addArgumentReturnedAttrs(Nodes.SCCNodes);
- Changed |= addReadAttrs(Nodes.SCCNodes, AARGetter);
- Changed |= addArgumentAttrs(Nodes.SCCNodes);
- Changed |= inferConvergent(Nodes.SCCNodes);
- Changed |= addNoReturnAttrs(Nodes.SCCNodes);
- Changed |= addWillReturn(Nodes.SCCNodes);
+ SmallSet<Function *, 8> Changed;
+
+ addArgumentReturnedAttrs(Nodes.SCCNodes, Changed);
+ addReadAttrs(Nodes.SCCNodes, AARGetter, Changed);
+ addArgumentAttrs(Nodes.SCCNodes, Changed);
+ inferConvergent(Nodes.SCCNodes, Changed);
+ addNoReturnAttrs(Nodes.SCCNodes, Changed);
+ addWillReturn(Nodes.SCCNodes, Changed);
// If we have no external nodes participating in the SCC, we can deduce some
// more precise attributes as well.
if (!Nodes.HasUnknownCall) {
- Changed |= addNoAliasAttrs(Nodes.SCCNodes);
- Changed |= addNonNullAttrs(Nodes.SCCNodes);
- Changed |= inferAttrsFromFunctionBodies(Nodes.SCCNodes);
- Changed |= addNoRecurseAttrs(Nodes.SCCNodes);
+ addNoAliasAttrs(Nodes.SCCNodes, Changed);
+ addNonNullAttrs(Nodes.SCCNodes, Changed);
+ inferAttrsFromFunctionBodies(Nodes.SCCNodes, Changed);
+ addNoRecurseAttrs(Nodes.SCCNodes, Changed);
}
- Changed |= addNoSyncAttr(Nodes.SCCNodes);
+ addNoSyncAttr(Nodes.SCCNodes, Changed);
// Finally, infer the maximal set of attributes from the ones we've inferred
// above. This is handling the cases where one attribute on a signature
@@ -1812,7 +1801,8 @@ static bool deriveAttrsInPostOrder(ArrayRef<Function *> Functions,
// the later is missing (or simply less sophisticated).
for (Function *F : Nodes.SCCNodes)
if (F)
- Changed |= inferAttributesFromOthers(*F);
+ if (inferAttributesFromOthers(*F))
+ Changed.insert(F);
return Changed;
}
@@ -1835,14 +1825,14 @@ PreservedAnalyses PostOrderFunctionAttrsPass::run(LazyCallGraph::SCC &C,
Functions.push_back(&N.getFunction());
}
- if (deriveAttrsInPostOrder(Functions, AARGetter)) {
- // We have not changed the call graph or removed/added functions.
- PreservedAnalyses PA;
- PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
- return PA;
- }
+ auto ChangedFunctions = deriveAttrsInPostOrder(Functions, AARGetter);
+ if (ChangedFunctions.empty())
+ return PreservedAnalyses::all();
- return PreservedAnalyses::all();
+ PreservedAnalyses PA;
+ // We have not added or removed functions.
+ PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
+ return PA;
}
namespace {
@@ -1887,7 +1877,7 @@ static bool runImpl(CallGraphSCC &SCC, AARGetterT AARGetter) {
Functions.push_back(I->getFunction());
}
- return deriveAttrsInPostOrder(Functions, AARGetter);
+ return !deriveAttrsInPostOrder(Functions, AARGetter).empty();
}
bool PostOrderFunctionAttrsLegacyPass::runOnSCC(CallGraphSCC &SCC) {
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