[clang] a89fb29 - [clang][ItaniumMangle] Check SizeExpr for DependentSizedArrayType

[via cfe-commits]

Author: oToToT
Date: 2021-04-02T15:31:20+08:00
New Revision: a89fb29398dc0ce48dfe6f45f99d6ae7df4c6b46

URL: https://github.com/llvm/llvm-project/commit/a89fb29398dc0ce48dfe6f45f99d6ae7df4c6b46
DIFF: https://github.com/llvm/llvm-project/commit/a89fb29398dc0ce48dfe6f45f99d6ae7df4c6b46.diff

LOG: [clang][ItaniumMangle] Check SizeExpr for DependentSizedArrayType
(PR49478)

As ArrayType::ArrayType mentioned in clang/lib/AST/Type.cpp, a
DependentSizedArrayType might not have size expression because it it
used as the type of a dependent array of unknown bound with a dependent
braced initializer.

Thus, I add a check when mangling array of that type.

This should fix https://bugs.llvm.org/show_bug.cgi?id=49478

Reviewed By: Richard Smith - zygoloid

Differential Revision: https://reviews.llvm.org/D99407

Added: 
    

Modified: 
    clang/lib/AST/ItaniumMangle.cpp
    clang/unittests/AST/DeclTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 3e6e29207f08c..6415fcab52c1c 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -3204,7 +3204,11 @@ void CXXNameMangler::mangleType(const VariableArrayType *T) {
 }
 void CXXNameMangler::mangleType(const DependentSizedArrayType *T) {
   Out << 'A';
-  mangleExpression(T->getSizeExpr());
+  // A DependentSizedArrayType might not have size expression as below
+  //
+  // template<int ...N> int arr[] = {N...};
+  if (T->getSizeExpr())
+    mangleExpression(T->getSizeExpr());
   Out << '_';
   mangleType(T->getElementType());
 }

diff  --git a/clang/unittests/AST/DeclTest.cpp b/clang/unittests/AST/DeclTest.cpp
index 08b1fbb5eb8ae..55d0a3fc065d5 100644
--- a/clang/unittests/AST/DeclTest.cpp
+++ b/clang/unittests/AST/DeclTest.cpp
@@ -104,3 +104,37 @@ TEST(Decl, AsmLabelAttr) {
   ASSERT_TRUE(0 == MangleF.compare("\x01" "foo"));
   ASSERT_TRUE(0 == MangleG.compare("goo"));
 }
+
+TEST(Decl, MangleDependentSizedArray) {
+  StringRef Code = R"(
+    template <int ...N>
+    int A[] = {N...};
+
+    template <typename T, int N>
+    struct S {
+      T B[N];
+    };
+  )";
+  auto AST =
+      tooling::buildASTFromCodeWithArgs(Code, {"-target", "i386-apple-darwin"});
+  ASTContext &Ctx = AST->getASTContext();
+  assert(Ctx.getTargetInfo().getDataLayout().getGlobalPrefix() &&
+         "Expected target to have a global prefix");
+  DiagnosticsEngine &Diags = AST->getDiagnostics();
+
+  const auto *DeclA =
+      selectFirst<VarDecl>("A", match(varDecl().bind("A"), Ctx));
+  const auto *DeclB =
+      selectFirst<FieldDecl>("B", match(fieldDecl().bind("B"), Ctx));
+
+  std::string MangleA, MangleB;
+  llvm::raw_string_ostream OS_A(MangleA), OS_B(MangleB);
+  std::unique_ptr<ItaniumMangleContext> MC(
+      ItaniumMangleContext::create(Ctx, Diags));
+
+  MC->mangleTypeName(DeclA->getType(), OS_A);
+  MC->mangleTypeName(DeclB->getType(), OS_B);
+
+  ASSERT_TRUE(0 == MangleA.compare("_ZTSA_i"));
+  ASSERT_TRUE(0 == MangleB.compare("_ZTSAT0__T_"));
+}