[clang] 3b7af27 - Revert "Revert "[-Wunsafe-buffer-usage] Initial commit - Transition away from raw buffers.""
Artem Dergachev via cfe-commits
cfe-commits at lists.llvm.org
Thu Dec 8 17:06:35 PST 2022
Author: Artem Dergachev
Date: 2022-12-08T16:57:59-08:00
New Revision: 3b7af2796b3d1a578b7e256f5e5b60e61108ec8d
URL: https://github.com/llvm/llvm-project/commit/3b7af2796b3d1a578b7e256f5e5b60e61108ec8d
DIFF: https://github.com/llvm/llvm-project/commit/3b7af2796b3d1a578b7e256f5e5b60e61108ec8d.diff
LOG: Revert "Revert "[-Wunsafe-buffer-usage] Initial commit - Transition away from raw buffers.""
This reverts commit bc0617795f8bdcd5deab3e48b120107cc2833cdc.
Be more careful with #includes to avoid linker errors on some buildbots.
Added:
clang/include/clang/Analysis/Analyses/UnsafeBufferUsage.h
clang/lib/Analysis/UnsafeBufferUsage.cpp
clang/test/SemaCXX/warn-unsafe-buffer-usage.cpp
Modified:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Analysis/CMakeLists.txt
clang/lib/Sema/AnalysisBasedWarnings.cpp
Removed:
################################################################################
diff --git a/clang/include/clang/Analysis/Analyses/UnsafeBufferUsage.h b/clang/include/clang/Analysis/Analyses/UnsafeBufferUsage.h
new file mode 100644
index 0000000000000..41ca359a73239
--- /dev/null
+++ b/clang/include/clang/Analysis/Analyses/UnsafeBufferUsage.h
@@ -0,0 +1,39 @@
+//===- UnsafeBufferUsage.h - Replace pointers with modern C++ ---*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines an analysis that aids replacing buffer accesses through
+// raw pointers with safer C++ abstractions such as containers and views/spans.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_ANALYSIS_ANALYSES_UNSAFEBUFFERUSAGE_H
+#define LLVM_CLANG_ANALYSIS_ANALYSES_UNSAFEBUFFERUSAGE_H
+
+#include "clang/AST/Decl.h"
+#include "clang/AST/Stmt.h"
+
+namespace clang {
+
+/// The interface that lets the caller handle unsafe buffer usage analysis
+/// results by overriding this class's handle... methods.
+class UnsafeBufferUsageHandler {
+public:
+ UnsafeBufferUsageHandler() = default;
+ virtual ~UnsafeBufferUsageHandler() = default;
+
+ /// Invoked when an unsafe operation over raw pointers is found.
+ virtual void handleUnsafeOperation(const Stmt *Operation) = 0;
+};
+
+// This function invokes the analysis and allows the caller to react to it
+// through the handler class.
+void checkUnsafeBufferUsage(const Decl *D, UnsafeBufferUsageHandler &Handler);
+
+} // end namespace clang
+
+#endif /* LLVM_CLANG_ANALYSIS_ANALYSES_UNSAFEBUFFERUSAGE_H */
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 51f1e95eff49f..939162273c708 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -11735,4 +11735,9 @@ def err_cast_from_randomized_struct : Error<
// LoongArch-specific Diagnostics
def err_loongarch_builtin_requires_la64 : Error<
"this builtin requires target: loongarch64">;
+
+// Unsafe buffer usage diagnostics.
+def warn_unsafe_buffer_usage : Warning<
+ "unchecked operation on raw buffer in expression">,
+ InGroup<DiagGroup<"unsafe-buffer-usage">>, DefaultIgnore;
} // end of sema component.
diff --git a/clang/lib/Analysis/CMakeLists.txt b/clang/lib/Analysis/CMakeLists.txt
index 16e3f474060cb..ea6cb59e8e199 100644
--- a/clang/lib/Analysis/CMakeLists.txt
+++ b/clang/lib/Analysis/CMakeLists.txt
@@ -32,6 +32,7 @@ add_clang_library(clangAnalysis
ThreadSafetyLogical.cpp
ThreadSafetyTIL.cpp
UninitializedValues.cpp
+ UnsafeBufferUsage.cpp
LINK_LIBS
clangAST
diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp b/clang/lib/Analysis/UnsafeBufferUsage.cpp
new file mode 100644
index 0000000000000..5e8ff29d51c38
--- /dev/null
+++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -0,0 +1,80 @@
+//===- UnsafeBufferUsage.cpp - Replace pointers with modern C++ -----------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/Analyses/UnsafeBufferUsage.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "llvm/ADT/SmallVector.h"
+
+using namespace llvm;
+using namespace clang;
+using namespace ast_matchers;
+
+namespace {
+// TODO: Better abstractions over gadgets.
+using GadgetList = std::vector<const Stmt *>;
+}
+
+// Scan the function and return a list of gadgets found with provided kits.
+static GadgetList findGadgets(const Decl *D) {
+
+ class GadgetFinderCallback : public MatchFinder::MatchCallback {
+ GadgetList &Output;
+
+ public:
+ GadgetFinderCallback(GadgetList &Output) : Output(Output) {}
+
+ void run(const MatchFinder::MatchResult &Result) override {
+ Output.push_back(Result.Nodes.getNodeAs<Stmt>("root_node"));
+ }
+ };
+
+ GadgetList G;
+ MatchFinder M;
+
+ auto IncrementMatcher = unaryOperator(
+ hasOperatorName("++"),
+ hasUnaryOperand(hasType(pointerType()))
+ );
+ auto DecrementMatcher = unaryOperator(
+ hasOperatorName("--"),
+ hasUnaryOperand(hasType(pointerType()))
+ );
+
+ GadgetFinderCallback CB(G);
+
+ M.addMatcher(
+ stmt(forEachDescendant(
+ stmt(
+ anyOf(
+ IncrementMatcher,
+ DecrementMatcher
+ /* Fill me in! */
+ )
+ // FIXME: Idiomatically there should be a forCallable(equalsNode(D))
+ // here, to make sure that the statement actually belongs to the
+ // function and not to a nested function. However, forCallable uses
+ // ParentMap which can't be used before the AST is fully constructed.
+ // The original problem doesn't sound like it needs ParentMap though,
+ // maybe there's a more direct solution?
+ ).bind("root_node")
+ )), &CB);
+
+ M.match(*D->getBody(), D->getASTContext());
+
+ return G; // NRVO!
+}
+
+void clang::checkUnsafeBufferUsage(const Decl *D,
+ UnsafeBufferUsageHandler &Handler) {
+ assert(D && D->getBody());
+
+ GadgetList G = findGadgets(D);
+ for (const Stmt *S : G) {
+ Handler.handleUnsafeOperation(S);
+ }
+}
diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index 9780a0aba7498..70b81c00904af 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -29,6 +29,7 @@
#include "clang/Analysis/Analyses/ReachableCode.h"
#include "clang/Analysis/Analyses/ThreadSafety.h"
#include "clang/Analysis/Analyses/UninitializedValues.h"
+#include "clang/Analysis/Analyses/UnsafeBufferUsage.h"
#include "clang/Analysis/AnalysisDeclContext.h"
#include "clang/Analysis/CFG.h"
#include "clang/Analysis/CFGStmtMap.h"
@@ -2138,6 +2139,23 @@ class ConsumedWarningsHandler : public ConsumedWarningsHandlerBase {
} // namespace consumed
} // namespace clang
+//===----------------------------------------------------------------------===//
+// Unsafe buffer usage analysis.
+//===----------------------------------------------------------------------===//
+
+class UnsafeBufferUsageReporter : public UnsafeBufferUsageHandler {
+ Sema &S;
+
+public:
+ UnsafeBufferUsageReporter(Sema &S) : S(S) {}
+
+ void handleUnsafeOperation(const Stmt *Operation) override {
+ S.Diag(Operation->getBeginLoc(), diag::warn_unsafe_buffer_usage)
+ << Operation->getSourceRange();
+ }
+};
+
+
//===----------------------------------------------------------------------===//
// AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based
// warnings on a function, method, or block.
@@ -2430,6 +2448,12 @@ void clang::sema::AnalysisBasedWarnings::IssueWarnings(
if (S.getLangOpts().CPlusPlus && isNoexcept(FD))
checkThrowInNonThrowingFunc(S, FD, AC);
+ // Emit unsafe buffer usage warnings and fixits.
+ if (!Diags.isIgnored(diag::warn_unsafe_buffer_usage, D->getBeginLoc())) {
+ UnsafeBufferUsageReporter R(S);
+ checkUnsafeBufferUsage(D, R);
+ }
+
// If none of the previous checks caused a CFG build, trigger one here
// for the logical error handler.
if (LogicalErrorHandler::hasActiveDiagnostics(Diags, D->getBeginLoc())) {
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage.cpp b/clang/test/SemaCXX/warn-unsafe-buffer-usage.cpp
new file mode 100644
index 0000000000000..59f830d29e3b9
--- /dev/null
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage.cpp
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -Wunsafe-buffer-usage -verify %s
+
+void testIncrement(char *p) {
+ ++p; // expected-warning{{unchecked operation on raw buffer in expression}}
+ p++; // expected-warning{{unchecked operation on raw buffer in expression}}
+ --p; // expected-warning{{unchecked operation on raw buffer in expression}}
+ p--; // expected-warning{{unchecked operation on raw buffer in expression}}
+}
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