https://gcc.gnu.org/g:b0e56bc6ad9fc54841070d676bc2bd9b5e2f8b6d
commit r16-5185-gb0e56bc6ad9fc54841070d676bc2bd9b5e2f8b6d Author: Eric Botcazou <[email protected]> Date: Wed Nov 12 09:03:18 2025 +0100 Ada: Fix variable initialized with if-expression not flagged as constant This is a regression present on the mainline and 15 branch: the -gnatwk switch no longer flags a string variable initialized with an if-expression as constant when it is not modified in the program. The fix is to set the Has_Initial_Value and Never_Set_In_Source flags earlier during analysis in the Analyze_Object_Declaration procedure. gcc/ada/ PR ada/122640 * sem_ch3.adb (Analyze_Object_Declaration): Set Is_True_Constant on entry for constants and Never_Set_In_Source in all cases. If an initialization expression is present, set Has_Initial_Value and Is_True_Constant on variables. gcc/testsuite/ * gnat.dg/warn34.adb: New test. Diff: --- gcc/ada/sem_ch3.adb | 75 ++++++++++++++++------------------------ gcc/testsuite/gnat.dg/warn34.adb | 9 +++++ 2 files changed, 39 insertions(+), 45 deletions(-) diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb index ba0af27471d8..cc26ecab6ae1 100644 --- a/gcc/ada/sem_ch3.adb +++ b/gcc/ada/sem_ch3.adb @@ -4415,10 +4415,17 @@ package body Sem_Ch3 is begin if Constant_Present (N) then Mutate_Ekind (Id, E_Constant); + Set_Is_True_Constant (Id); else Mutate_Ekind (Id, E_Variable); end if; + -- Indicate this is not set in source. Certainly true for constants, and + -- true for variables so far (will be reset for a variable if and when + -- we encounter a modification in the source). + + Set_Never_Set_In_Source (Id); + -- There are three kinds of implicit types generated by an -- object declaration: @@ -4701,17 +4708,23 @@ package body Sem_Ch3 is Set_Etype (E, T); end if; - -- If an initialization expression is present, then we set the - -- Is_True_Constant flag. It will be reset if this is a variable - -- and it is indeed modified. - - Set_Is_True_Constant (Id, True); - -- If we are analyzing a constant declaration, set its completion -- flag after analyzing and resolving the expression. if Constant_Present (N) then Set_Has_Completion (Id); + + -- Set Has_Initial_Value if initialization expression present. Note + -- that if there is no initializing expression, we leave the state + -- of this flag unchanged (usually it will be False, but notably in + -- the case of exception choice variables, it will already be true). + + -- Set Is_True_Constant if initialization expression is present. It + -- will be reset if the variable is indeed modified. + + else + Set_Has_Initial_Value (Id); + Set_Is_True_Constant (Id); end if; -- Set type and resolve (type may be overridden later on) @@ -5120,15 +5133,6 @@ package body Sem_Ch3 is -- that subsequent uses of this entity are not rejected -- via the same mechanism that (correctly) rejects -- "X : Integer := X;". - - if Constant_Present (N) then - Set_Is_True_Constant (Id); - else - if Present (E) then - Set_Has_Initial_Value (Id); - end if; - end if; - goto Leave; end if; @@ -5261,43 +5265,24 @@ package body Sem_Ch3 is Check_Wide_Character_Restriction (T, Object_Definition (N)); - -- Indicate this is not set in source. Certainly true for constants, and - -- true for variables so far (will be reset for a variable if and when - -- we encounter a modification in the source). - - Set_Never_Set_In_Source (Id); - -- Now establish the proper kind and type of the object if Ekind (Id) = E_Void then Reinit_Field_To_Zero (Id, F_Next_Inlined_Subprogram); end if; - if Constant_Present (N) then - Set_Is_True_Constant (Id); + -- A variable is set as shared passive if it appears in a shared + -- passive package, and is at the outer level. This is not done for + -- entities generated during expansion, because those are always + -- manipulated locally. - else - -- A variable is set as shared passive if it appears in a shared - -- passive package, and is at the outer level. This is not done for - -- entities generated during expansion, because those are always - -- manipulated locally. - - if Is_Shared_Passive (Current_Scope) - and then Is_Library_Level_Entity (Id) - and then Comes_From_Source (Id) - then - Set_Is_Shared_Passive (Id); - Check_Shared_Var (Id, T, N); - end if; - - -- Set Has_Initial_Value if initializing expression present. Note - -- that if there is no initializing expression, we leave the state - -- of this flag unchanged (usually it will be False, but notably in - -- the case of exception choice variables, it will already be true). - - if Present (E) then - Set_Has_Initial_Value (Id); - end if; + if not Constant_Present (N) + and then Is_Shared_Passive (Current_Scope) + and then Is_Library_Level_Entity (Id) + and then Comes_From_Source (Id) + then + Set_Is_Shared_Passive (Id); + Check_Shared_Var (Id, T, N); end if; -- Set the SPARK mode from the current context (may be overwritten later diff --git a/gcc/testsuite/gnat.dg/warn34.adb b/gcc/testsuite/gnat.dg/warn34.adb new file mode 100644 index 000000000000..57318a075493 --- /dev/null +++ b/gcc/testsuite/gnat.dg/warn34.adb @@ -0,0 +1,9 @@ +-- { dg-do compile } +-- { dg-options "-gnatwk" } + +function Warn34 (F : Boolean) return String is + S : String := -- { dg-warning "could be declared constant" } + (if F then "foo" else "bar"); +begin + return S; +end;
