Translate CXXScalarValueInitExpr

Summary:
public
This expression is used to value-initialize non-class types. Per definition of value initialization for non-class types:
1. If it's an array, value-initialize each of its elements
2. Otherwise, zero-initialize it
http://en.cppreference.com/w/cpp/language/value_initialization

I was unable to reproduce (1) in a way that produced CXXScalarValueInitExpr and so this diff
deals with case (2)

Reviewed By: jvillard

Differential Revision: D2901311

fb-gh-sync-id: beeafa2

infer/src/clang/cTrans.ml

@@ -363,6 +363,18 @@ struct
       exps = [(exp, typ)];
       ids = ids; }
 
+  let cxxScalarValueInitExpr_trans trans_state stmt_info expr_info =
+    let typ = CTypes_decl.get_type_from_expr_info expr_info trans_state.context.CContext.tenv in
+    (* constant will be different depending on type *)
+    let zero_opt = match typ with
+      | Sil.Tfloat _ -> Some (Sil.Cfloat 0.0)
+      | Sil.Tptr _ -> Some (Sil.Cint Sil.Int.null)
+      | Sil.Tvoid -> None
+      | _ -> Some (Sil.Cint Sil.Int.zero) in
+    match zero_opt with
+    | Some zero -> { empty_res_trans with exps = [(Sil.Const zero, typ)] }
+    | _ -> empty_res_trans
+
   let nullStmt_trans succ_nodes stmt_info =
     { empty_res_trans with root_nodes = succ_nodes }
 
@@ -2151,6 +2163,9 @@ struct
     | FloatingLiteral (stmt_info, stmts, expr_info, float_string) ->
         floatingLiteral_trans trans_state stmt_info expr_info float_string
 
+    | CXXScalarValueInitExpr (stmt_info, stmts, expr_info) ->
+        cxxScalarValueInitExpr_trans trans_state stmt_info expr_info
+
     | ObjCBoxedExpr (stmt_info, stmts, info, sel) ->
         objCBoxedExpr_trans trans_state info sel stmt_info stmts
 

infer/tests/codetoanalyze/cpp/frontend/literals/scalar_value_init.cpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2016 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+enum ENUM {
+  val1,
+  val2
+};
+
+template<class T> T get() {
+  return T();
+}
+
+void test() {
+  int i = get<int>();
+  float f = get<float>();
+  float* fp = get<float*>();
+  get<void>();
+  ENUM x = get<ENUM>();
+  float f2 = float();
+}

infer/tests/codetoanalyze/cpp/frontend/literals/scalar_value_init.cpp.dot

@@ -0,0 +1,88 @@
+digraph iCFG {
+23 [label="23:  DeclStmt \n   n$3=_fun_get<int>() [line 20]\n  *&i:int =n$3 [line 20]\n  REMOVE_TEMPS(n$3); [line 20]\n  NULLIFY(&i,false); [line 20]\n " shape="box"]
+	
+
+	 23 -> 22 ;
+22 [label="22:  DeclStmt \n   n$2=_fun_get<float>() [line 21]\n  *&f:float =n$2 [line 21]\n  REMOVE_TEMPS(n$2); [line 21]\n  NULLIFY(&f,false); [line 21]\n " shape="box"]
+	
+
+	 22 -> 21 ;
+21 [label="21:  DeclStmt \n   n$1=_fun_get<float *>() [line 22]\n  *&fp:float *=n$1 [line 22]\n  REMOVE_TEMPS(n$1); [line 22]\n  NULLIFY(&fp,false); [line 22]\n " shape="box"]
+	
+
+	 21 -> 20 ;
+20 [label="20:  Call _fun_get<void> \n   _fun_get<void>() [line 23]\n " shape="box"]
+	
+
+	 20 -> 19 ;
+19 [label="19:  DeclStmt \n   n$0=_fun_get<ENUM>() [line 24]\n  *&x:int =n$0 [line 24]\n  REMOVE_TEMPS(n$0); [line 24]\n  NULLIFY(&x,false); [line 24]\n " shape="box"]
+	
+
+	 19 -> 18 ;
+18 [label="18:  DeclStmt \n   *&f2:float =0.000000 [line 25]\n  NULLIFY(&f2,false); [line 25]\n  APPLY_ABSTRACTION; [line 25]\n " shape="box"]
+	
+
+	 18 -> 17 ;
+17 [label="17: Exit test \n  " color=yellow style=filled]
+	
+
+16 [label="16: Start test\nFormals: \nLocals:  f2:float  x:int  fp:float * f:float  i:int  \n   DECLARE_LOCALS(&return,&f2,&x,&fp,&f,&i); [line 19]\n  NULLIFY(&f,false); [line 19]\n  NULLIFY(&f2,false); [line 19]\n  NULLIFY(&fp,false); [line 19]\n  NULLIFY(&i,false); [line 19]\n  NULLIFY(&x,false); [line 19]\n " color=yellow style=filled]
+	
+
+	 16 -> 23 ;
+15 [label="15:  Return Stmt \n   *&return:int =0 [line 16]\n  APPLY_ABSTRACTION; [line 16]\n " shape="box"]
+	
+
+	 15 -> 14 ;
+14 [label="14: Exit get<ENUM> \n  " color=yellow style=filled]
+	
+
+13 [label="13: Start get<ENUM>\nFormals: \nLocals:  \n   DECLARE_LOCALS(&return); [line 15]\n " color=yellow style=filled]
+	
+
+	 13 -> 15 ;
+12 [label="12:  Return Stmt \n   *&return:void =-1 [line 16]\n  APPLY_ABSTRACTION; [line 16]\n " shape="box"]
+	
+
+	 12 -> 11 ;
+11 [label="11: Exit get<void> \n  " color=yellow style=filled]
+	
+
+10 [label="10: Start get<void>\nFormals: \nLocals:  \n   DECLARE_LOCALS(&return); [line 15]\n " color=yellow style=filled]
+	
+
+	 10 -> 12 ;
+9 [label="9:  Return Stmt \n   *&return:float *=null [line 16]\n  APPLY_ABSTRACTION; [line 16]\n " shape="box"]
+	
+
+	 9 -> 8 ;
+8 [label="8: Exit get<float *> \n  " color=yellow style=filled]
+	
+
+7 [label="7: Start get<float *>\nFormals: \nLocals:  \n   DECLARE_LOCALS(&return); [line 15]\n " color=yellow style=filled]
+	
+
+	 7 -> 9 ;
+6 [label="6:  Return Stmt \n   *&return:float =0.000000 [line 16]\n  APPLY_ABSTRACTION; [line 16]\n " shape="box"]
+	
+
+	 6 -> 5 ;
+5 [label="5: Exit get<float> \n  " color=yellow style=filled]
+	
+
+4 [label="4: Start get<float>\nFormals: \nLocals:  \n   DECLARE_LOCALS(&return); [line 15]\n " color=yellow style=filled]
+	
+
+	 4 -> 6 ;
+3 [label="3:  Return Stmt \n   *&return:int =0 [line 16]\n  APPLY_ABSTRACTION; [line 16]\n " shape="box"]
+	
+
+	 3 -> 2 ;
+2 [label="2: Exit get<int> \n  " color=yellow style=filled]
+	
+
+1 [label="1: Start get<int>\nFormals: \nLocals:  \n   DECLARE_LOCALS(&return); [line 15]\n " color=yellow style=filled]
+	
+
+	 1 -> 3 ;
+}

infer/tests/frontend/cpp/LiteralsTest.java

@@ -24,10 +24,18 @@ public class LiteralsTest {
   public DebuggableTemporaryFolder folder = new DebuggableTemporaryFolder();
 
   @Test
-  public void whenCaptureRunCommaThenDotFilesAreTheSame()
+  public void whenCaptureRunNullptrThenDotFilesAreTheSame()
       throws InterruptedException, IOException, InferException {
     String src =
         "infer/tests/codetoanalyze/cpp/frontend/literals/nullptr.cpp";
     ClangFrontendUtils.createAndCompareCppDotFiles(folder, src);
   }
+
+  @Test
+  public void whenCaptureRunScalarValueInitThenDotFilesAreTheSame()
+      throws InterruptedException, IOException, InferException {
+    String src =
+        "infer/tests/codetoanalyze/cpp/frontend/literals/scalar_value_init.cpp";
+    ClangFrontendUtils.createAndCompareCppDotFiles(folder, src);
+  }
 }