ymandel created this revision.
ymandel added reviewers: xazax.hun, samestep, sgatev, gribozavr.
Herald added subscribers: martong, tschuett, rnkovacs.
Herald added a reviewer: NoQ.
Herald added a project: All.
ymandel requested review of this revision.
Herald added a project: clang.
This patch modifies context-sensitive analysis of functions to use a cache,
rather than recreate the `ControlFlowContext` from a function decl on each
encounter. However, this is just step 1 (of N) in adding support for a
configurable map of "modeled" function decls. The map will go from the actual
function decl to the `ControlFlowContext` used to model it. Only functions
pre-configured in the map will be modeled in a context-sensitive way.
We start with a cache because it introduces the desired map, while retaining the
current behavior. Here, functions are mapped to their actual implementations
(when available).
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D131039
Files:
clang/include/clang/Analysis/FlowSensitive/ControlFlowContext.h
clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h
clang/lib/Analysis/FlowSensitive/ControlFlowContext.cpp
clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
clang/lib/Analysis/FlowSensitive/Transfer.cpp
Index: clang/lib/Analysis/FlowSensitive/Transfer.cpp
===================================================================
--- clang/lib/Analysis/FlowSensitive/Transfer.cpp
+++ clang/lib/Analysis/FlowSensitive/Transfer.cpp
@@ -507,28 +507,27 @@
return;
Env.setStorageLocation(*S, *ArgLoc);
} else if (const FunctionDecl *F = S->getDirectCallee()) {
- // This case is for context-sensitive analysis, which we only do if we
- // have the callee body available in the translation unit.
- if (!Options.ContextSensitive || F->getBody() == nullptr)
+ // This case is for context-sensitive analysis.
+ if (!Options.ContextSensitive)
+ return;
+
+ const ControlFlowContext *CFCtx = Env.getControlFlowContext(F);
+ if (!CFCtx)
return;
// FIXME: We don't support context-sensitive analysis of recursion, so
// we should return early here if `F` is the same as the `FunctionDecl`
// holding `S` itself.
- auto &ASTCtx = F->getASTContext();
-
- // FIXME: Cache these CFGs.
- auto CFCtx = ControlFlowContext::build(F, F->getBody(), &ASTCtx);
- // FIXME: Handle errors here and below.
- assert(CFCtx);
auto ExitBlock = CFCtx->getCFG().getExit().getBlockID();
auto CalleeEnv = Env.pushCall(S);
- // FIXME: Use the same analysis as the caller for the callee.
- DataflowAnalysisOptions Options;
- auto Analysis = NoopAnalysis(ASTCtx, Options);
+ // FIXME: Use the same analysis as the caller for the callee. Note,
+ // though, that doing so would require support for changing the analysis's
+ // ASTContext.
+ auto Analysis = NoopAnalysis(CFCtx->getDecl().getASTContext(),
+ DataflowAnalysisOptions());
auto BlockToOutputState =
dataflow::runDataflowAnalysis(*CFCtx, Analysis, CalleeEnv);
Index: clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
===================================================================
--- clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
+++ clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
@@ -16,6 +16,7 @@
#include "clang/AST/ExprCXX.h"
#include "clang/Analysis/FlowSensitive/DebugSupport.h"
#include "clang/Analysis/FlowSensitive/Value.h"
+#include "clang/Basic/IdentifierTable.h"
#include "llvm/Support/Debug.h"
#include <cassert>
#include <memory>
@@ -335,6 +336,30 @@
llvm::dbgs() << debugString(Constraints, AtomNames);
}
+const ControlFlowContext *
+DataflowAnalysisContext::getControlFlowContext(const FunctionDecl *F) {
+ // FIXME: This is an expensive approach since we *always* print the fully
+ // qualified name. Instead, we should prefilter by some means (e.g. checking
+ // the identifier against a set).
+ std::string QualName;
+ llvm::raw_string_ostream OS(QualName);
+ F->printQualifiedName(OS);
+ auto It = FunctionModels.find(QualName);
+ if (It != FunctionModels.end())
+ return &It->second;
+
+ if (F->getBody() != nullptr) {
+ auto CFCtx =
+ ControlFlowContext::build(F, F->getBody(), &F->getASTContext());
+ // FIXME: Handle errors.
+ assert(CFCtx);
+ auto Result = FunctionModels.insert({QualName, std::move(*CFCtx)});
+ return &Result.first->second;
+ }
+
+ return nullptr;
+}
+
} // namespace dataflow
} // namespace clang
Index: clang/lib/Analysis/FlowSensitive/ControlFlowContext.cpp
===================================================================
--- clang/lib/Analysis/FlowSensitive/ControlFlowContext.cpp
+++ clang/lib/Analysis/FlowSensitive/ControlFlowContext.cpp
@@ -64,7 +64,7 @@
llvm::DenseMap<const Stmt *, const CFGBlock *> StmtToBlock =
buildStmtToBasicBlockMap(*Cfg);
- return ControlFlowContext(std::move(Cfg), std::move(StmtToBlock));
+ return ControlFlowContext(D, std::move(Cfg), std::move(StmtToBlock));
}
} // namespace dataflow
Index: clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h
===================================================================
--- clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h
+++ clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h
@@ -19,6 +19,7 @@
#include "clang/AST/DeclBase.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Type.h"
+#include "clang/Analysis/FlowSensitive/ControlFlowContext.h"
#include "clang/Analysis/FlowSensitive/DataflowAnalysisContext.h"
#include "clang/Analysis/FlowSensitive/DataflowLattice.h"
#include "clang/Analysis/FlowSensitive/StorageLocation.h"
@@ -343,6 +344,12 @@
/// imply that `Val` is true.
bool flowConditionImplies(BoolValue &Val) const;
+ /// Returns the `ControlFlowContext` registered for `F`, if any. Otherwise,
+ /// returns null.
+ const ControlFlowContext *getControlFlowContext(const FunctionDecl *F) {
+ return DACtx->getControlFlowContext(F);
+ }
+
LLVM_DUMP_METHOD void dump() const;
private:
Index: clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
===================================================================
--- clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
+++ clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
@@ -18,6 +18,7 @@
#include "clang/AST/Decl.h"
#include "clang/AST/Expr.h"
#include "clang/AST/TypeOrdering.h"
+#include "clang/Analysis/FlowSensitive/ControlFlowContext.h"
#include "clang/Analysis/FlowSensitive/Solver.h"
#include "clang/Analysis/FlowSensitive/StorageLocation.h"
#include "clang/Analysis/FlowSensitive/Value.h"
@@ -254,6 +255,10 @@
LLVM_DUMP_METHOD void dumpFlowCondition(AtomicBoolValue &Token);
+ /// Returns the `ControlFlowContext` registered for `F`, if any. Otherwise,
+ /// returns null.
+ const ControlFlowContext *getControlFlowContext(const FunctionDecl *F);
+
private:
struct NullableQualTypeDenseMapInfo : private llvm::DenseMapInfo<QualType> {
static QualType getEmptyKey() {
@@ -360,6 +365,9 @@
llvm::DenseMap<AtomicBoolValue *, llvm::DenseSet<AtomicBoolValue *>>
FlowConditionDeps;
llvm::DenseMap<AtomicBoolValue *, BoolValue *> FlowConditionConstraints;
+
+ // Keyed on the function's fully qualified name. No leading "::".
+ llvm::StringMap<ControlFlowContext> FunctionModels;
};
} // namespace dataflow
Index: clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
===================================================================
--- clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
+++ clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
@@ -20,7 +20,6 @@
#include "clang/AST/ASTContext.h"
#include "clang/AST/Stmt.h"
-#include "clang/Analysis/CFG.h"
#include "clang/Analysis/FlowSensitive/ControlFlowContext.h"
#include "clang/Analysis/FlowSensitive/DataflowEnvironment.h"
#include "clang/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.h"
Index: clang/include/clang/Analysis/FlowSensitive/ControlFlowContext.h
===================================================================
--- clang/include/clang/Analysis/FlowSensitive/ControlFlowContext.h
+++ clang/include/clang/Analysis/FlowSensitive/ControlFlowContext.h
@@ -30,10 +30,14 @@
/// analysis.
class ControlFlowContext {
public:
- /// Builds a ControlFlowContext from an AST node.
+ /// Builds a ControlFlowContext from an AST node. `D` is the function in which
+ /// `S` resides. All arguments must be non-null.
static llvm::Expected<ControlFlowContext> build(const Decl *D, Stmt *S,
ASTContext *C);
+ /// Returns the `Decl` containing the statement used to construct the CFG.
+ const Decl &getDecl() const { return *ContainingDecl; }
+
/// Returns the CFG that is stored in this context.
const CFG &getCFG() const { return *Cfg; }
@@ -43,10 +47,17 @@
}
private:
- ControlFlowContext(std::unique_ptr<CFG> Cfg,
+ // `D` must not be null.
+ ControlFlowContext(const Decl *D, std::unique_ptr<CFG> Cfg,
llvm::DenseMap<const Stmt *, const CFGBlock *> StmtToBlock)
- : Cfg(std::move(Cfg)), StmtToBlock(std::move(StmtToBlock)) {}
+ : ContainingDecl(D), Cfg(std::move(Cfg)),
+ StmtToBlock(std::move(StmtToBlock)) {
+ assert(D != nullptr);
+ assert(Cfg != nullptr);
+ }
+ /// The `Decl` containing the statement used to construct the CFG.
+ const Decl *ContainingDecl;
std::unique_ptr<CFG> Cfg;
llvm::DenseMap<const Stmt *, const CFGBlock *> StmtToBlock;
};
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