diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ada/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/ada/sinfo.ads | 43 |
2 files changed, 22 insertions, 26 deletions
diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog index e9b1c3f..26af730 100644 --- a/gcc/ada/ChangeLog +++ b/gcc/ada/ChangeLog @@ -1,5 +1,10 @@ 2019-07-22 Eric Botcazou <ebotcazou@adacore.com> + * sinfo.ads: Update the documentation about the + Do_Division_Check, Do_Overflow_Check and Do_Range_Check flags. + +2019-07-22 Eric Botcazou <ebotcazou@adacore.com> + * exp_ch4.adb (Expand_N_Type_Conversion): Beef up comment. (Fixup_Universal_Fixed_Operation): Set the base type instead of the type of the enclosing type conversion on the operation. diff --git a/gcc/ada/sinfo.ads b/gcc/ada/sinfo.ads index 6310016..064147e 100644 --- a/gcc/ada/sinfo.ads +++ b/gcc/ada/sinfo.ads @@ -755,14 +755,15 @@ package Sinfo is -- Do_Division_Check flag on float exponentiation expressions, for the case -- where the value is 0.0 and the exponent is negative, although this case -- does lead to a division check failure. As another special case, - -- the frontend does not insert a Do_Range_Check on an allocator where + -- the front end does not insert a Do_Range_Check on an allocator where -- the designated type is scalar, and the designated type is more -- constrained than the type of the initialized allocator value or the type -- of the default value for an uninitialized allocator. - -- Note: the expander always takes care of the Do_Range check case, - -- so this flag will never be set in the expanded tree passed to the - -- back end code generator. + -- Note that the expander always takes care of the Do_Range_Check case, so + -- this flag will never be set in the expanded tree passed to the back end. + -- For the other two flags, the check can be generated either by the back + -- end or by the front end, depending on the setting of a target parameter. -- Note that this accounts for all nodes that trigger the corresponding -- checks, except for range checks on subtype_indications, which may be @@ -1186,9 +1187,10 @@ package Sinfo is -- conversion nodes (and set if the conversion requires a check). -- Do_Division_Check (Flag13-Sem) - -- This flag is set on a division operator (/ mod rem) to indicate - -- that a zero divide check is required. The actual check is dealt - -- with by the backend (all the front end does is to set the flag). + -- This flag is set on a division operator (/ mod rem) to indicate that + -- a zero divide check is required. The actual check is either dealt with + -- by the back end if Backend_Divide_Checks is set to true, or by the + -- front end itself if it is set to false. -- Do_Length_Check (Flag4-Sem) -- This flag is set in an N_Assignment_Statement, N_Op_And, N_Op_Or, @@ -1197,15 +1199,13 @@ package Sinfo is -- Do_Overflow_Check (Flag17-Sem) -- This flag is set on an operator where an overflow check is required on - -- the operation. The actual check is dealt with by the backend (all the - -- front end does is to set the flag). The other cases where this flag is - -- used is on a Type_Conversion node and for attribute reference nodes. + -- the operation. The actual check is either dealt with by the back end + -- if Backend_Overflow_Checks is set to true, or by the front end itself + -- if it is set to false. The other cases where this flag is used is on a + -- Type_Conversion node as well on if and case expression nodes. -- For a type conversion, it means that the conversion is from one base -- type to another, and the value may not fit in the target base type. - -- See also the description of Do_Range_Check for this case. The only - -- attribute references which use this flag are Pred and Succ, where it - -- means that the result should be checked for going outside the base - -- range. Note that this flag is not set for modular types. This flag is + -- See also the description of Do_Range_Check for this case. This flag is -- also set on if and case expression nodes if we are operating in either -- MINIMIZED or ELIMINATED overflow checking mode (to make sure that we -- properly process overflow checking for dependent expressions). @@ -1215,9 +1215,9 @@ package Sinfo is -- range check is required. The target type is clear from the context. -- The contexts in which this flag can appear are the following: - -- Right side of an assignment. In this case the target type is - -- taken from the left side of the assignment, which is referenced - -- by the Name of the N_Assignment_Statement node. + -- Right side of an assignment. In this case the target type is taken + -- from the left side of the assignment, which is referenced by the + -- Name of the N_Assignment_Statement node. -- Subscript expressions in an indexed component. In this case the -- target type is determined from the type of the array, which is @@ -1251,15 +1251,6 @@ package Sinfo is -- listed above (e.g. in a return statement), an additional type -- conversion node is introduced to represent the required check. - -- A special case arises for the arguments of the Pred/Succ attributes. - -- Here the range check needed is against First + 1 .. Last (Pred) or - -- First .. Last - 1 (Succ) of the corresponding base type. Essentially - -- these checks are what would be performed within the implicit body of - -- the functions that correspond to these attributes. In these cases, - -- the Do_Range check flag is set on the argument to the attribute - -- function, and the back end must special case the appropriate range - -- to check against. - -- Do_Storage_Check (Flag17-Sem) -- This flag is set in an N_Allocator node to indicate that a storage -- check is required for the allocation, or in an N_Subprogram_Body node |