[clang] 827ba67 - [Sema] Validate calls to GetExprRange.

[Mark de Wever via cfe-commits]

Author: Mark de Wever
Date: 2020-08-16T18:32:38+02:00
New Revision: 827ba67e383313b05e9b10c8215e501530d6c9e3

URL: https://github.com/llvm/llvm-project/commit/827ba67e383313b05e9b10c8215e501530d6c9e3
DIFF: https://github.com/llvm/llvm-project/commit/827ba67e383313b05e9b10c8215e501530d6c9e3.diff

LOG: [Sema] Validate calls to GetExprRange.

When a conditional expression has a throw expression it called
GetExprRange with a void expression, which caused an assertion failure.

This approach was suggested by Richard Smith.

Fixes PR46484: Clang crash in clang/lib/Sema/SemaChecking.cpp:10028

Differential Revision: https://reviews.llvm.org/D85601

Added: 
    

Modified: 
    clang/lib/Sema/SemaChecking.cpp
    clang/test/SemaCXX/conditional-expr.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index bbd856e9262e..4efd62f58d2e 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -10368,10 +10368,16 @@ static IntRange GetExprRange(ASTContext &C, const Expr *E, unsigned MaxWidth,
                           MaxWidth, InConstantContext);
 
     // Otherwise, conservatively merge.
-    IntRange L =
-        GetExprRange(C, CO->getTrueExpr(), MaxWidth, InConstantContext);
-    IntRange R =
-        GetExprRange(C, CO->getFalseExpr(), MaxWidth, InConstantContext);
+    // GetExprRange requires an integer expression, but a throw expression
+    // results in a void type.
+    Expr *E = CO->getTrueExpr();
+    IntRange L = E->getType()->isVoidType()
+                     ? IntRange{0, true}
+                     : GetExprRange(C, E, MaxWidth, InConstantContext);
+    E = CO->getFalseExpr();
+    IntRange R = E->getType()->isVoidType()
+                     ? IntRange{0, true}
+                     : GetExprRange(C, E, MaxWidth, InConstantContext);
     return IntRange::join(L, R);
   }
 

diff  --git a/clang/test/SemaCXX/conditional-expr.cpp b/clang/test/SemaCXX/conditional-expr.cpp
index 8d0555ea5068..68e23a1f5727 100644
--- a/clang/test/SemaCXX/conditional-expr.cpp
+++ b/clang/test/SemaCXX/conditional-expr.cpp
@@ -409,3 +409,20 @@ namespace lifetime_extension {
     D d = b ? D{B()} : D{C()};
   }
 }
+
+namespace PR46484 {
+// expected-error at +4{{expected ':'}}
+// expected-note at +3{{to match this '?'}}
+// expected-warning at +2{{variable 'b' is uninitialized}}
+// expected-error at +1 2 {{expected ';' after top level declarator}}
+int a long b = a = b ? throw 0 1
+
+void g() {
+  extern int a;
+  extern long b;
+  long c = a = b ? throw 0 : 1;
+  long d = a = b ? 1 : throw 0;
+  // expected-error at +1 {{assigning to 'int' from incompatible type 'void'}}
+  long e = a = b ? throw 0 : throw 1;
+}
+} // namespace PR46484