[clang] [clang][dataflow] Allow `DataflowAnalysisContext` to use a non-owned `Solver`. (PR #91316)

[via cfe-commits]

https://github.com/martinboehme updated https://github.com/llvm/llvm-project/pull/91316

>From abb7d53778394a220353deeeb86fbd06bf4352c2 Mon Sep 17 00:00:00 2001
From: Martin Braenne <mboehme at google.com>
Date: Tue, 7 May 2024 10:23:16 +0000
Subject: [PATCH 1/2] [clang][dataflow] Allow `DataflowAnalysisContext` to use
 a non-owned `Solver`.

For some callers (see change in DataflowAnalysis.h), this is more convenient.
---
 .../Analysis/FlowSensitive/DataflowAnalysis.h |  5 ++---
 .../FlowSensitive/DataflowAnalysisContext.h   | 20 +++++++++++++++++--
 .../FlowSensitive/DataflowAnalysisContext.cpp | 10 +++++-----
 3 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h b/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
index 67eccdd030dcdd..763af244547647 100644
--- a/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
+++ b/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
@@ -283,9 +283,8 @@ llvm::Expected<llvm::SmallVector<Diagnostic>> diagnoseFunction(
   if (!Context)
     return Context.takeError();
 
-  auto OwnedSolver = std::make_unique<WatchedLiteralsSolver>(MaxSATIterations);
-  const WatchedLiteralsSolver *Solver = OwnedSolver.get();
-  DataflowAnalysisContext AnalysisContext(std::move(OwnedSolver));
+  auto Solver = std::make_unique<WatchedLiteralsSolver>(MaxSATIterations);
+  DataflowAnalysisContext AnalysisContext(*Solver);
   Environment Env(AnalysisContext, FuncDecl);
   AnalysisT Analysis = createAnalysis<AnalysisT>(ASTCtx, Env);
   llvm::SmallVector<Diagnostic> Diagnostics;
diff --git a/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h b/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
index aa2c366cb164a9..13a74281e02b5d 100644
--- a/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
+++ b/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
@@ -67,7 +67,19 @@ class DataflowAnalysisContext {
   DataflowAnalysisContext(std::unique_ptr<Solver> S,
                           Options Opts = Options{
                               /*ContextSensitiveOpts=*/std::nullopt,
-                              /*Logger=*/nullptr});
+                              /*Logger=*/nullptr})
+      : DataflowAnalysisContext(*S, std::move(S), Opts) {}
+
+  /// Constructs a dataflow analysis context.
+  ///
+  /// Requirements:
+  ///
+  ///  `S` must outlive the `DataflowAnalysisContext`.
+  DataflowAnalysisContext(Solver &S, Options Opts = Options{
+                                         /*ContextSensitiveOpts=*/std::nullopt,
+                                         /*Logger=*/nullptr})
+      : DataflowAnalysisContext(S, nullptr, Opts) {}
+
   ~DataflowAnalysisContext();
 
   /// Sets a callback that returns the names and types of the synthetic fields
@@ -209,6 +221,9 @@ class DataflowAnalysisContext {
     using DenseMapInfo::isEqual;
   };
 
+  DataflowAnalysisContext(Solver &S, std::unique_ptr<Solver> OwnedSolver,
+                          Options Opts);
+
   // Extends the set of modeled field declarations.
   void addModeledFields(const FieldSet &Fields);
 
@@ -232,7 +247,8 @@ class DataflowAnalysisContext {
            Solver::Result::Status::Unsatisfiable;
   }
 
-  std::unique_ptr<Solver> S;
+  Solver &S;
+  std::unique_ptr<Solver> OwnedSolver;
   std::unique_ptr<Arena> A;
 
   // Maps from program declarations and statements to storage locations that are
diff --git a/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp b/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
index e94fd39c45dc15..3041dcf6d500c5 100644
--- a/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
+++ b/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
@@ -170,7 +170,7 @@ DataflowAnalysisContext::joinFlowConditions(Atom FirstToken,
 
 Solver::Result DataflowAnalysisContext::querySolver(
     llvm::SetVector<const Formula *> Constraints) {
-  return S->solve(Constraints.getArrayRef());
+  return S.solve(Constraints.getArrayRef());
 }
 
 bool DataflowAnalysisContext::flowConditionImplies(Atom Token,
@@ -338,10 +338,10 @@ static std::unique_ptr<Logger> makeLoggerFromCommandLine() {
   return Logger::html(std::move(StreamFactory));
 }
 
-DataflowAnalysisContext::DataflowAnalysisContext(std::unique_ptr<Solver> S,
-                                                 Options Opts)
-    : S(std::move(S)), A(std::make_unique<Arena>()), Opts(Opts) {
-  assert(this->S != nullptr);
+DataflowAnalysisContext::DataflowAnalysisContext(
+    Solver &S, std::unique_ptr<Solver> OwnedSolver, Options Opts)
+    : S(S), OwnedSolver(std::move(OwnedSolver)), A(std::make_unique<Arena>()),
+      Opts(Opts) {
   // If the -dataflow-log command-line flag was set, synthesize a logger.
   // This is ugly but provides a uniform method for ad-hoc debugging dataflow-
   // based tools.

>From 6112536c0f400c10b919532d2b171c37d0d435ac Mon Sep 17 00:00:00 2001
From: Martin Braenne <mboehme at google.com>
Date: Tue, 7 May 2024 12:53:16 +0000
Subject: [PATCH 2/2] fixup! [clang][dataflow] Allow `DataflowAnalysisContext`
 to use a non-owned `Solver`.

---
 .../clang/Analysis/FlowSensitive/DataflowAnalysisContext.h  | 6 +++++-
 .../lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp  | 2 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h b/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
index 13a74281e02b5d..5be4a1145f40d7 100644
--- a/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
+++ b/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
@@ -221,7 +221,11 @@ class DataflowAnalysisContext {
     using DenseMapInfo::isEqual;
   };
 
-  DataflowAnalysisContext(Solver &S, std::unique_ptr<Solver> OwnedSolver,
+  /// `S` is the solver to use. `OwnedSolver` may be:
+  /// *  Null (in which case `S` is non-onwed and must outlive this object), or
+  /// *  Non-null (in which case it must refer to `S`, and the
+  ///    `DataflowAnalysisContext will take ownership of `OwnedSolver`).
+  DataflowAnalysisContext(Solver &S, std::unique_ptr<Solver> &&OwnedSolver,
                           Options Opts);
 
   // Extends the set of modeled field declarations.
diff --git a/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp b/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
index 3041dcf6d500c5..4b86daa56d7b52 100644
--- a/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
+++ b/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
@@ -339,7 +339,7 @@ static std::unique_ptr<Logger> makeLoggerFromCommandLine() {
 }
 
 DataflowAnalysisContext::DataflowAnalysisContext(
-    Solver &S, std::unique_ptr<Solver> OwnedSolver, Options Opts)
+    Solver &S, std::unique_ptr<Solver> &&OwnedSolver, Options Opts)
     : S(S), OwnedSolver(std::move(OwnedSolver)), A(std::make_unique<Arena>()),
       Opts(Opts) {
   // If the -dataflow-log command-line flag was set, synthesize a logger.