[PATCH] D118260: [clangd][Hover] Suppress initializers with many tokens

[Kadir Cetinkaya via Phabricator via cfe-commits]

kadircet updated this revision to Diff 403583.
kadircet added a comment.

- Add comments about why we suppress initializer printing


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D118260/new/

https://reviews.llvm.org/D118260

Files:
  clang-tools-extra/clangd/Hover.cpp
  clang-tools-extra/clangd/unittests/HoverTests.cpp


Index: clang-tools-extra/clangd/unittests/HoverTests.cpp
===================================================================
--- clang-tools-extra/clangd/unittests/HoverTests.cpp
+++ clang-tools-extra/clangd/unittests/HoverTests.cpp
@@ -3172,6 +3172,20 @@
   EXPECT_EQ(H->Type, HoverInfo::PrintedType("m_int"));
 }
 
+TEST(Hover, HideBigInitializers) {
+  Annotations T(R"cpp(
+  #define A(x) x, x, x, x
+  #define B(x) A(A(A(A(x))))
+  int a^rr[] = {B(0)};
+  )cpp");
+
+  TestTU TU = TestTU::withCode(T.code());
+  auto AST = TU.build();
+  auto H = getHover(AST, T.point(), format::getLLVMStyle(), nullptr);
+
+  ASSERT_TRUE(H);
+  EXPECT_EQ(H->Definition, "int arr[]");
+}
 } // namespace
 } // namespace clangd
 } // namespace clang
Index: clang-tools-extra/clangd/Hover.cpp
===================================================================
--- clang-tools-extra/clangd/Hover.cpp
+++ clang-tools-extra/clangd/Hover.cpp
@@ -126,7 +126,17 @@
   return "";
 }
 
-std::string printDefinition(const Decl *D, const PrintingPolicy &PP) {
+std::string printDefinition(const Decl *D, PrintingPolicy PP,
+                            const syntax::TokenBuffer &TB) {
+  if (auto *VD = llvm::dyn_cast<VarDecl>(D)) {
+    if (auto *IE = VD->getInit()) {
+      // Initializers might be huge and result in lots of memory allocations in
+      // some catostrophic cases. Such long lists are not useful in hover cards
+      // anyway.
+      if (200 < TB.expandedTokens(IE->getSourceRange()).size())
+        PP.SuppressInitializers = true;
+    }
+  }
   std::string Definition;
   llvm::raw_string_ostream OS(Definition);
   D->print(OS, PP);
@@ -568,7 +578,8 @@
 
 /// Generate a \p Hover object given the declaration \p D.
 HoverInfo getHoverContents(const NamedDecl *D, const PrintingPolicy &PP,
-                           const SymbolIndex *Index) {
+                           const SymbolIndex *Index,
+                           const syntax::TokenBuffer &TB) {
   HoverInfo HI;
   const ASTContext &Ctx = D->getASTContext();
 
@@ -630,7 +641,7 @@
       HI.Value = toString(ECD->getInitVal(), 10);
   }
 
-  HI.Definition = printDefinition(D, PP);
+  HI.Definition = printDefinition(D, PP, TB);
   return HI;
 }
 
@@ -1029,7 +1040,7 @@
       auto Decls = explicitReferenceTargets(N->ASTNode, DeclRelation::Alias,
                                             AST.getHeuristicResolver());
       if (!Decls.empty()) {
-        HI = getHoverContents(Decls.front(), PP, Index);
+        HI = getHoverContents(Decls.front(), PP, Index, TB);
         // Layout info only shown when hovering on the field/class itself.
         if (Decls.front() == N->ASTNode.get<Decl>())
           addLayoutInfo(*Decls.front(), *HI);


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