[clang-tools-extra] a90d57b - [clangd] Improve PopulateSwitch tweak

[David Goldman via cfe-commits]

Author: David Goldman
Date: 2021-10-04T10:15:37-04:00
New Revision: a90d57b6cc5f1237199fa6974eeb1cb168a7aed3

URL: https://github.com/llvm/llvm-project/commit/a90d57b6cc5f1237199fa6974eeb1cb168a7aed3
DIFF: https://github.com/llvm/llvm-project/commit/a90d57b6cc5f1237199fa6974eeb1cb168a7aed3.diff

LOG: [clangd] Improve PopulateSwitch tweak

- Support enums in C and ObjC as their
  AST representations differ slightly.

- Add support for typedef'ed enums.

Differential Revision: https://reviews.llvm.org/D110954

Added: 
    

Modified: 
    clang-tools-extra/clangd/refactor/tweaks/PopulateSwitch.cpp
    clang-tools-extra/clangd/unittests/tweaks/PopulateSwitchTests.cpp

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clangd/refactor/tweaks/PopulateSwitch.cpp b/clang-tools-extra/clangd/refactor/tweaks/PopulateSwitch.cpp
index 40af43fef4aaf..4e2b15b8f22af 100644
--- a/clang-tools-extra/clangd/refactor/tweaks/PopulateSwitch.cpp
+++ b/clang-tools-extra/clangd/refactor/tweaks/PopulateSwitch.cpp
@@ -113,7 +113,8 @@ bool PopulateSwitch::prepare(const Selection &Sel) {
     return false;
   // Ignore implicit casts, since enums implicitly cast to integer types.
   Cond = Cond->IgnoreParenImpCasts();
-  EnumT = Cond->getType()->getAsAdjusted<EnumType>();
+  // Get the canonical type to handle typedefs.
+  EnumT = Cond->getType().getCanonicalType()->getAsAdjusted<EnumType>();
   if (!EnumT)
     return false;
   EnumD = EnumT->getDecl();
@@ -152,14 +153,30 @@ bool PopulateSwitch::prepare(const Selection &Sel) {
     if (CS->caseStmtIsGNURange())
       return false;
 
+    // Support for direct references to enum constants. This is required to
+    // support C and ObjC which don't contain values in their ConstantExprs.
+    // The general way to get the value of a case is EvaluateAsRValue, but we'd
+    // rather not deal with that in case the AST is broken.
+    if (auto *DRE = dyn_cast<DeclRefExpr>(CS->getLHS()->IgnoreParenCasts())) {
+      if (auto *Enumerator = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
+        auto Iter = ExpectedCases.find(Normalize(Enumerator->getInitVal()));
+        if (Iter != ExpectedCases.end())
+          Iter->second.setCovered();
+        continue;
+      }
+    }
+
+    // ConstantExprs with values are expected for C++, otherwise the storage
+    // kind will be None.
+
     // Case expression is not a constant expression or is value-dependent,
     // so we may not be able to work out which cases are covered.
     const ConstantExpr *CE = dyn_cast<ConstantExpr>(CS->getLHS());
     if (!CE || CE->isValueDependent())
       return false;
 
-    // Unsure if this case could ever come up, but prevents an unreachable
-    // executing in getResultAsAPSInt.
+    // We need a stored value in order to continue; currently both C and ObjC
+    // enums won't have one.
     if (CE->getResultStorageKind() == ConstantExpr::RSK_None)
       return false;
     auto Iter = ExpectedCases.find(Normalize(CE->getResultAsAPSInt()));

diff  --git a/clang-tools-extra/clangd/unittests/tweaks/PopulateSwitchTests.cpp b/clang-tools-extra/clangd/unittests/tweaks/PopulateSwitchTests.cpp
index 13277c99cc314..05833736f3113 100644
--- a/clang-tools-extra/clangd/unittests/tweaks/PopulateSwitchTests.cpp
+++ b/clang-tools-extra/clangd/unittests/tweaks/PopulateSwitchTests.cpp
@@ -23,6 +23,7 @@ TEST_F(PopulateSwitchTest, Test) {
     CodeContext Context;
     llvm::StringRef TestSource;
     llvm::StringRef ExpectedSource;
+    llvm::StringRef FileName = "TestTU.cpp";
   };
 
   Case Cases[]{
@@ -206,10 +207,43 @@ TEST_F(PopulateSwitchTest, Test) {
           R""(template<typename T> void f() {enum Enum {A}; ^switch (A) {}})"",
           "unavailable",
       },
+      {// C: Only filling in missing enumerators
+       Function,
+       R""(
+            enum CEnum {A,B,C};
+            enum CEnum val = A;
+            ^switch (val) {case B:break;}
+          )"",
+       R""(
+            enum CEnum {A,B,C};
+            enum CEnum val = A;
+            switch (val) {case B:break;case A:case C:break;}
+          )"",
+       "TestTU.c"},
+      {// C: Only filling in missing enumerators w/ typedefs
+       Function,
+       R""(
+            typedef unsigned long UInteger;
+            enum ControlState : UInteger;
+            typedef enum ControlState ControlState;
+            enum ControlState : UInteger {A,B,C};
+            ControlState controlState = A;
+            switch (^controlState) {case A:break;}
+          )"",
+       R""(
+            typedef unsigned long UInteger;
+            enum ControlState : UInteger;
+            typedef enum ControlState ControlState;
+            enum ControlState : UInteger {A,B,C};
+            ControlState controlState = A;
+            switch (controlState) {case A:break;case B:case C:break;}
+          )"",
+       "TestTU.c"},
   };
 
   for (const auto &Case : Cases) {
     Context = Case.Context;
+    FileName = Case.FileName;
     EXPECT_EQ(apply(Case.TestSource), Case.ExpectedSource);
   }
 }