From ac633fb5c4b46f1e716a20fd1c0198035ff47217 Mon Sep 17 00:00:00 2001
From: Artem Dergachev <artem.dergachev@gmail.com>
Date: Sat, 10 Feb 2018 00:55:49 +0000
Subject: [PATCH] [analyzer] Add missing pre-post-statement callbacks for
 OffsetOfExpr.

This expression may or may not be evaluated in compile time, so tracking the
result symbol is of potential interest. However, run-time offsetof is not yet
supported by the analyzer, so for now this callback is only there to assist
future implementation.

Patch by Henry Wong!

Differential Revision: https://reviews.llvm.org/D42300


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@324790 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../Checkers/AnalysisOrderChecker.cpp               | 12 ++++++++++++
 lib/StaticAnalyzer/Core/ExprEngine.cpp              | 13 ++++++++++---
 test/Analysis/Inputs/system-header-simulator.h      |  4 +++-
 test/Analysis/offsetofexpr-callback.c               | 13 +++++++++++++
 4 files changed, 38 insertions(+), 4 deletions(-)
 create mode 100644 test/Analysis/offsetofexpr-callback.c

diff --git a/lib/StaticAnalyzer/Checkers/AnalysisOrderChecker.cpp b/lib/StaticAnalyzer/Checkers/AnalysisOrderChecker.cpp
index dc9dd5bd06..e4cdc500de 100644
--- a/lib/StaticAnalyzer/Checkers/AnalysisOrderChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/AnalysisOrderChecker.cpp
@@ -33,6 +33,8 @@ class AnalysisOrderChecker
                      check::PostStmt<ArraySubscriptExpr>,
                      check::PreStmt<CXXNewExpr>,
                      check::PostStmt<CXXNewExpr>,
+                     check::PreStmt<OffsetOfExpr>,
+                     check::PostStmt<OffsetOfExpr>,
                      check::PreCall,
                      check::PostCall,
                      check::NewAllocator,
@@ -91,6 +93,16 @@ public:
       llvm::errs() << "PostStmt<CXXNewExpr>\n";
   }
 
+  void checkPreStmt(const OffsetOfExpr *OOE, CheckerContext &C) const {
+    if (isCallbackEnabled(C, "PreStmtOffsetOfExpr"))
+      llvm::errs() << "PreStmt<OffsetOfExpr>\n";
+  }
+
+  void checkPostStmt(const OffsetOfExpr *OOE, CheckerContext &C) const {
+    if (isCallbackEnabled(C, "PostStmtOffsetOfExpr"))
+      llvm::errs() << "PostStmt<OffsetOfExpr>\n";
+  }
+
   void checkPreCall(const CallEvent &Call, CheckerContext &C) const {
     if (isCallbackEnabled(C, "PreCall")) {
       llvm::errs() << "PreCall";
diff --git a/lib/StaticAnalyzer/Core/ExprEngine.cpp b/lib/StaticAnalyzer/Core/ExprEngine.cpp
index fef7116d90..210cea6818 100644
--- a/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -1543,12 +1543,19 @@ void ExprEngine::Visit(const Stmt *S, ExplodedNode *Pred,
       Bldr.addNodes(Dst);
       break;
 
-    case Stmt::OffsetOfExprClass:
+    case Stmt::OffsetOfExprClass: {
       Bldr.takeNodes(Pred);
-      VisitOffsetOfExpr(cast<OffsetOfExpr>(S), Pred, Dst);
+      ExplodedNodeSet PreVisit;
+      getCheckerManager().runCheckersForPreStmt(PreVisit, Pred, S, *this);
+
+      ExplodedNodeSet PostVisit;
+      for (ExplodedNode *Node : PreVisit)
+        VisitOffsetOfExpr(cast<OffsetOfExpr>(S), Node, PostVisit);
+
+      getCheckerManager().runCheckersForPostStmt(Dst, PostVisit, S, *this);
       Bldr.addNodes(Dst);
       break;
-
+    }
     case Stmt::UnaryExprOrTypeTraitExprClass:
       Bldr.takeNodes(Pred);
       VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
diff --git a/test/Analysis/Inputs/system-header-simulator.h b/test/Analysis/Inputs/system-header-simulator.h
index ff69a1502b..8542387d42 100644
--- a/test/Analysis/Inputs/system-header-simulator.h
+++ b/test/Analysis/Inputs/system-header-simulator.h
@@ -110,4 +110,6 @@ void _Exit(int status) __attribute__ ((__noreturn__));
 #ifndef NULL
 #define __DARWIN_NULL 0
 #define NULL __DARWIN_NULL
-#endif
\ No newline at end of file
+#endif
+
+#define offsetof(t, d) __builtin_offsetof(t, d)
\ No newline at end of file
diff --git a/test/Analysis/offsetofexpr-callback.c b/test/Analysis/offsetofexpr-callback.c
new file mode 100644
index 0000000000..0fcb90797d
--- /dev/null
+++ b/test/Analysis/offsetofexpr-callback.c
@@ -0,0 +1,13 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=debug.AnalysisOrder -analyzer-config debug.AnalysisOrder:PreStmtOffsetOfExpr=true,debug.AnalysisOrder:PostStmtOffsetOfExpr=true %s 2>&1 | FileCheck %s
+#include "Inputs/system-header-simulator.h"
+
+struct S {
+  char c;
+};
+
+void test() {
+  offsetof(struct S, c); 
+}
+
+// CHECK: PreStmt<OffsetOfExpr>
+// CHECK-NEXT: PostStmt<OffsetOfExpr>
\ No newline at end of file
-- 
2.40.0