[gcc r13-530] [Ada] Initialize Compiler_State to avoid Constraint_Error

[gcc r13-530] [Ada] Initialize Compiler_State to avoid Constraint_Error

[Pierre-Marie de Rodat]

https://gcc.gnu.org/g:83bfddac6feff4dcacc2b93e2357629a3bfa971b

commit r13-530-g83bfddac6feff4dcacc2b93e2357629a3bfa971b
Author: Etienne Servais <servais@adacore.com>
Date:   Tue Oct 26 17:00:24 2021 +0200

    [Ada] Initialize Compiler_State to avoid Constraint_Error
    
    When building gnat1 with `-gnatVa` as we do locally, rules like: `gcc -c
    -gnatyM79 <any adb file with lines longer than 79>` will throw a
    constraint error as `lib.compiler_state` is initialized by par.adb, ie
    after scanning. Therefore any error_msg thrown during scanning will
    perform this uninitialized read (which raises a Constraint_Error when
    the compiler was compiled with `-gnatVa`).
    
    Initialize this flag to `Parsing`.
    
    gcc/ada/
    
            * lib.ads: initialize `Compiler_State` to `Parsing`.

Diff:
---
 gcc/ada/lib.ads | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/ada/lib.ads b/gcc/ada/lib.ads
index 4a799130a4b..e29d42af570 100644
--- a/gcc/ada/lib.ads
+++ b/gcc/ada/lib.ads
@@ -39,7 +39,7 @@ package Lib is
    --  Type to hold list of indirect references to unit number table
 
    type Compiler_State_Type is (Parsing, Analyzing);
-   Compiler_State : Compiler_State_Type;
+   Compiler_State : Compiler_State_Type := Parsing;
    --  Indicates current state of compilation. This is used to implement the
    --  function In_Extended_Main_Source_Unit.