Hoist const variables from goto_block (#182)

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -474,7 +474,8 @@ bool Converter::ConvertVarDeclSkipInit(clang::VarDecl *decl) {
   auto *method_or_null =
       curr_function_ ? clang::dyn_cast<clang::CXXMethodDecl>(curr_function_)
                      : nullptr;
-  if (!qual_type.isConstQualified() && !qual_type->isReferenceType() &&
+  if ((hoisted_decls_.contains(decl) || !qual_type.isConstQualified()) &&
+      !qual_type->isReferenceType() &&
       ((method_or_null == nullptr) || !method_or_null->isVirtual()) &&
       !IsGlobalVar(decl)) {
     StrCat(keyword_mut_);

tests/unit/goto_cleanup.c

@@ -7,8 +7,9 @@ static int early(int n) {
     goto out;
   }
   ret = 100;
+  const int intentionally_const_var = 22;
 out:
-  return ret;
+  return ret + intentionally_const_var - intentionally_const_var;
 }
 
 static int from_loop(int n) {

tests/unit/out/refcount/goto_cleanup.rs

@@ -9,6 +9,7 @@ use std::rc::{Rc, Weak};
 pub fn early_0(n: i32) -> i32 {
     let n: Value<i32> = Rc::new(RefCell::new(n));
     let ret: Value<i32> = <Value<i32>>::default();
+    let intentionally_const_var: Value<i32> = <Value<i32>>::default();
     goto_block!({
         '__entry: {
             *ret.borrow_mut() = 0;
@@ -17,9 +18,11 @@ pub fn early_0(n: i32) -> i32 {
                 goto!('out);
             }
             (*ret.borrow_mut()) = 100;
+            *intentionally_const_var.borrow_mut() = 22;
         }
         'out: {
-            return (*ret.borrow());
+            return (((*ret.borrow()) + (*intentionally_const_var.borrow()))
+                - (*intentionally_const_var.borrow()));
         }
     });
     panic!("ub: non-void function does not return a value")

tests/unit/out/unsafe/goto_cleanup.rs

@@ -8,6 +8,7 @@ use std::os::fd::{AsFd, FromRawFd, IntoRawFd};
 use std::rc::Rc;
 pub unsafe fn early_0(mut n: i32) -> i32 {
     let mut ret: i32 = 0_i32;
+    let mut intentionally_const_var: i32 = 0_i32;
     goto_block!({
         '__entry: {
             ret = 0;
@@ -16,9 +17,10 @@ pub unsafe fn early_0(mut n: i32) -> i32 {
                 goto!('out);
             }
             ret = 100;
+            intentionally_const_var = 22;
         }
         'out: {
-            return ret;
+            return (((ret) + (intentionally_const_var)) - (intentionally_const_var));
         }
     });
     panic!("ub: non-void function does not return a value")