[clang] [clang] StmtPrinter: Handle DeclRefExpr to a Decomposition (PR #125001)

Matheus Izvekov via cfe-commits cfe-commits at lists.llvm.org
Wed Jan 29 16:14:53 PST 2025


https://github.com/mizvekov created https://github.com/llvm/llvm-project/pull/125001

A DeclRefExpr could never refer to a Decomposition in valid C++ code, but somehow the Analyzer creates these entities and then it tries to print them.

There is no sensible answer here, so we print 'decomposition' followed by the names of all of its bindings, separated by dashes.

>From dfba1f75a95f714166ae5dc4c9f2bef0d85d61c7 Mon Sep 17 00:00:00 2001
From: Matheus Izvekov <mizvekov at gmail.com>
Date: Wed, 29 Jan 2025 21:07:15 -0300
Subject: [PATCH] [clang] StmtPrinter: Handle DeclRefExpr to a Decomposition

A DeclRefExpr could never refer to a Decomposition in valid C++ code,
but somehow the Analyzer creates these entities and then it tries to
print them.

There is no sensible answer here, so we print 'decomposition' followed
by the names of all of its bindings, separated by dashes.
---
 clang/lib/AST/StmtPrinter.cpp               |  7 ++
 clang/test/Analysis/anonymous-decls.cpp     | 89 +++++++++++++++++++++
 clang/test/Analysis/anonymous-parameter.cpp | 30 -------
 3 files changed, 96 insertions(+), 30 deletions(-)
 create mode 100644 clang/test/Analysis/anonymous-decls.cpp
 delete mode 100644 clang/test/Analysis/anonymous-parameter.cpp

diff --git a/clang/lib/AST/StmtPrinter.cpp b/clang/lib/AST/StmtPrinter.cpp
index 9efc88436f928d..280192fcc7984e 100644
--- a/clang/lib/AST/StmtPrinter.cpp
+++ b/clang/lib/AST/StmtPrinter.cpp
@@ -1291,6 +1291,13 @@ void StmtPrinter::VisitDeclRefExpr(DeclRefExpr *Node) {
          << PD->getFunctionScopeIndex();
       break;
     }
+    case Decl::Decomposition: {
+      auto *DD = cast<DecompositionDecl>(VD);
+      OS << "decomposition";
+      for (const auto &I : DD->bindings())
+        OS << '-' << I->getName();
+      break;
+    }
     default:
       llvm_unreachable("Unhandled anonymous declaration kind");
     }
diff --git a/clang/test/Analysis/anonymous-decls.cpp b/clang/test/Analysis/anonymous-decls.cpp
new file mode 100644
index 00000000000000..211184523aa51c
--- /dev/null
+++ b/clang/test/Analysis/anonymous-decls.cpp
@@ -0,0 +1,89 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=debug.DumpCFG -triple x86_64-apple-darwin12 -std=c++20 %s 2>&1 | FileCheck %s
+
+struct A {
+  static A a;
+  char b;
+  friend bool operator==(A, A) = default;
+};
+bool _ = A() == A::a;
+
+// FIXME: steps 1 and 5 show anonymous function parameters are
+// not handled correctly.
+
+// CHECK-LABEL: bool operator==(A, A) noexcept = default
+// CHECK-NEXT: [B2 (ENTRY)]
+// CHECK-NEXT:    Succs (1): B1
+// CHECK:      [B1]
+// CHECK-NEXT:    1: function-parameter-0-0
+// CHECK-NEXT:    2: [B1.1].b
+// CHECK-NEXT:    3: [B1.2] (ImplicitCastExpr, LValueToRValue, char)
+// CHECK-NEXT:    4: [B1.3] (ImplicitCastExpr, IntegralCast, int)
+// CHECK-NEXT:    5: function-parameter-0-1
+// CHECK-NEXT:    6: [B1.5].b
+// CHECK-NEXT:    7: [B1.6] (ImplicitCastExpr, LValueToRValue, char)
+// CHECK-NEXT:    8: [B1.7] (ImplicitCastExpr, IntegralCast, int)
+// CHECK-NEXT:    9: [B1.4] == [B1.8]
+// CHECK-NEXT:   10: return [B1.9];
+// CHECK-NEXT:    Preds (1): B2
+// CHECK-NEXT:    Succs (1): B0
+// CHECK:      [B0 (EXIT)]
+// CHECK-NEXT:    Preds (1): B1
+
+namespace std {
+template <class> struct iterator_traits;
+template <class, class> struct pair;
+template <class _Tp> struct iterator_traits<_Tp *> {
+  typedef _Tp &reference;
+};
+template <long, class> struct tuple_element;
+template <class> struct tuple_size;
+template <class _T1, class _T2> struct tuple_size<pair<_T1, _T2>> {
+  static const int value = 2;
+};
+template <class _T1, class _T2> struct tuple_element<0, pair<_T1, _T2>> {
+  using type = _T1;
+};
+template <class _T1, class _T2> struct tuple_element<1, pair<_T1, _T2>> {
+  using type = _T2;
+};
+template <long _Ip, class _T1, class _T2>
+tuple_element<_Ip, pair<_T1, _T2>>::type get(pair<_T1, _T2> &);
+struct __wrap_iter {
+  iterator_traits<pair<int, int> *>::reference operator*();
+  void operator++();
+};
+bool operator!=(__wrap_iter, __wrap_iter);
+struct vector {
+  __wrap_iter begin();
+  __wrap_iter end();
+};
+} // namespace std
+int main() {
+  std::vector v;
+  for (auto &[a, b] : v)
+    ;
+}
+
+// FIXME: On steps 8 and 14, a decomposition is referred by name, which they never have.
+
+// CHECK-LABEL: int main()
+// CHECK:      [B3]
+// CHECK-NEXT:   1: operator*
+// CHECK-NEXT:   2: [B3.1] (ImplicitCastExpr, FunctionToPointerDecay, iterator_traits<pair<int, int> *>::reference (*)(void))
+// CHECK-NEXT:   3: __begin1
+// CHECK-NEXT:   4: * [B3.3] (OperatorCall)
+// CHECK-NEXT:   5: auto &;
+// CHECK-NEXT:   6: get<0UL>
+// CHECK-NEXT:   7: [B3.6] (ImplicitCastExpr, FunctionToPointerDecay, typename tuple_element<0L, pair<int, int> >::type (*)(pair<int, int> &))
+// CHECK-NEXT:   8: decomposition-a-b
+// CHECK-NEXT:   9: [B3.7]([B3.8])
+// CHECK-NEXT:  10: [B3.9]
+// CHECK-NEXT:  11: std::tuple_element<0, std::pair<int, int>>::type a = get<0UL>(decomposition-a-b);
+// CHECK-NEXT:  12: get<1UL>
+// CHECK-NEXT:  13: [B3.12] (ImplicitCastExpr, FunctionToPointerDecay, typename tuple_element<1L, pair<int, int> >::type (*)(pair<int, int> &))
+// CHECK-NEXT:  14: decomposition-a-b
+// CHECK-NEXT:  15: [B3.13]([B3.14])
+// CHECK-NEXT:  16: [B3.15]
+// CHECK-NEXT:  17: std::tuple_element<1, std::pair<int, int>>::type b = get<1UL>(decomposition-a-b);
+// CHECK-NEXT:   Preds (1): B1
+// CHECK-NEXT:   Succs (1): B2
diff --git a/clang/test/Analysis/anonymous-parameter.cpp b/clang/test/Analysis/anonymous-parameter.cpp
deleted file mode 100644
index ad2a00b3329cb3..00000000000000
--- a/clang/test/Analysis/anonymous-parameter.cpp
+++ /dev/null
@@ -1,30 +0,0 @@
-// RUN: %clang_analyze_cc1 -analyzer-checker=debug.DumpCFG -triple x86_64-apple-darwin12 -std=c++20 %s 2>&1 | FileCheck %s
-
-struct A {
-  static A a;
-  char b;
-  friend bool operator==(A, A) = default;
-};
-bool _ = A() == A::a;
-
-// FIXME: steps 1 and 5 show anonymous function parameters are
-// not handled correctly.
-
-// CHECK-LABEL: bool operator==(A, A) noexcept = default
-// CHECK-NEXT: [B2 (ENTRY)]
-// CHECK-NEXT:    Succs (1): B1
-// CHECK:      [B1]
-// CHECK-NEXT:    1: function-parameter-0-0
-// CHECK-NEXT:    2: [B1.1].b
-// CHECK-NEXT:    3: [B1.2] (ImplicitCastExpr, LValueToRValue, char)
-// CHECK-NEXT:    4: [B1.3] (ImplicitCastExpr, IntegralCast, int)
-// CHECK-NEXT:    5: function-parameter-0-1
-// CHECK-NEXT:    6: [B1.5].b
-// CHECK-NEXT:    7: [B1.6] (ImplicitCastExpr, LValueToRValue, char)
-// CHECK-NEXT:    8: [B1.7] (ImplicitCastExpr, IntegralCast, int)
-// CHECK-NEXT:    9: [B1.4] == [B1.8]
-// CHECK-NEXT:   10: return [B1.9];
-// CHECK-NEXT:    Preds (1): B2
-// CHECK-NEXT:    Succs (1): B0
-// CHECK:      [B0 (EXIT)]
-// CHECK-NEXT:    Preds (1): B1



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