[clang] 36f6743 - [AST] Stop evaluate constant expression if the condition expression which in switch statement contains errors

[via cfe-commits]

Author: yronglin
Date: 2023-07-07T19:56:47+08:00
New Revision: 36f67434f724f2cdf36735b243fdaace726afb85

URL: https://github.com/llvm/llvm-project/commit/36f67434f724f2cdf36735b243fdaace726afb85
DIFF: https://github.com/llvm/llvm-project/commit/36f67434f724f2cdf36735b243fdaace726afb85.diff

LOG: [AST] Stop evaluate constant expression if the condition expression which in switch statement contains errors

This fix issue: https://github.com/llvm/llvm-project/issues/63453

```
constexpr int foo(unsigned char c) {
    switch (f) {
    case 0:
        return 7;
    default:
        break;
    }
    return 0;
}

static_assert(foo('d'));

```

Reviewed By: aaron.ballman, erichkeane, hokein

Differential Revision: https://reviews.llvm.org/D153296

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/lib/AST/ExprConstant.cpp
    clang/test/SemaCXX/constexpr-function-recovery-crash.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 8672b483cf836b..35caf85725c140 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -570,6 +570,9 @@ Bug Fixes in This Version
 - Clang now correctly evaluates ``__has_extension (cxx_defaulted_functions)``
   and ``__has_extension (cxx_default_function_template_args)`` to 1.
   (`#61758 <https://github.com/llvm/llvm-project/issues/61758>`_)
+- Stop evaluating a constant expression if the condition expression which in
+  switch statement contains errors.
+  (`#63453 <https://github.com/llvm/llvm-project/issues/63453>_`)
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

diff  --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 39e6b634eb2520..c740aecf32f154 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -5007,12 +5007,13 @@ static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
         !EvaluateDecl(Info, SS->getConditionVariable()))
       return ESR_Failed;
     if (SS->getCond()->isValueDependent()) {
-      if (!EvaluateDependentExpr(SS->getCond(), Info))
-        return ESR_Failed;
-    } else {
-      if (!EvaluateInteger(SS->getCond(), Value, Info))
-        return ESR_Failed;
+      // We don't know what the value is, and which branch should jump to.
+      EvaluateDependentExpr(SS->getCond(), Info);
+      return ESR_Failed;
     }
+    if (!EvaluateInteger(SS->getCond(), Value, Info))
+      return ESR_Failed;
+
     if (!CondScope.destroy())
       return ESR_Failed;
   }

diff  --git a/clang/test/SemaCXX/constexpr-function-recovery-crash.cpp b/clang/test/SemaCXX/constexpr-function-recovery-crash.cpp
index 07bc5e57ae13ce..8bada7c0b6df3e 100644
--- a/clang/test/SemaCXX/constexpr-function-recovery-crash.cpp
+++ b/clang/test/SemaCXX/constexpr-function-recovery-crash.cpp
@@ -87,6 +87,7 @@ constexpr int force12 = test12();          // expected-error {{must be initializ
 // We're not checking specific recovery here so don't assert diagnostics.
 TEST_EVALUATE(Switch, switch (!!){});              // expected-error + {{}}
 TEST_EVALUATE(SwitchInit, switch (auto x = !!){}); // expected-error + {{}}
+TEST_EVALUATE(SwitchCondValDep, switch (invalid_value) { default: break; });    // expected-error + {{}}
 TEST_EVALUATE(For, for (!!){}); // expected-error + {{}}
                                 // FIXME: should bail out instead of looping.
                                 // expected-note at -2 + {{infinite loop}}