------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S C O S -- -- -- -- S p e c -- -- -- -- Copyright (C) 2009-2011, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING3. If not, go to -- -- http://www.gnu.org/licenses for a complete copy of the license. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- This package defines tables used to store Source Coverage Obligations. It -- is used by Par_SCO to build the SCO information before writing it out to -- the ALI file, and by Get_SCO/Put_SCO to read and write the text form that -- is used in the ALI file. with Types; use Types; with GNAT.Table; package SCOs is -- SCO information can exist in one of two forms. In the ALI file, it is -- represented using a text format that is described in this specification. -- Internally it is stored using two tables SCO_Table and SCO_Unit_Table, -- which are also defined in this unit. -- Par_SCO is part of the compiler. It scans the parsed source tree and -- populates the internal tables. -- Get_SCO reads the text lines in ALI format and populates the internal -- tables with corresponding information. -- Put_SCO reads the internal tables and generates text lines in the ALI -- format. -------------------- -- SCO ALI Format -- -------------------- -- Source coverage obligations are generated on a unit-by-unit basis in the -- ALI file, using lines that start with the identifying character C. These -- lines are generated if the -gnateS switch is set. -- Sloc Ranges -- In several places in the SCO lines, Sloc ranges appear. These are used -- to indicate the first and last Sloc of some construct in the tree and -- they have the form: -- line:col-line:col -- Note that SCO's are generated only for generic templates, not for -- generic instances (since only the first are part of the source). So -- we don't need generic instantiation stuff in these line:col items. -- SCO File headers -- The SCO information follows the cross-reference information, so it -- need not be read by tools like gnatbind, gnatmake etc. The SCO output -- is divided into sections, one section for each unit for which SCO's -- are generated. A SCO section has a header of the form: -- C dependency-number filename -- This header precedes SCO information for the unit identified by -- dependency number and file name. The dependency number is the -- index into the generated D lines and is ones origin (i.e. 2 = -- reference to second generated D line). -- Note that the filename here will reflect the original name if -- a Source_Reference pragma was encountered (since all line number -- references will be with respect to the original file). -- Note: the filename is redundant in that it could be deduced from -- the corresponding D line, but it is convenient at least for human -- reading of the SCO information, and means that the SCO information -- can stand on its own without needing other parts of the ALI file. -- Statements -- For the purpose of SCO generation, the notion of statement includes -- simple statements and also the following declaration types: -- type_declaration -- subtype_declaration -- object_declaration -- renaming_declaration -- generic_instantiation -- and the following regions of the syntax tree: -- the part of a case_statement from CASE up to the expression -- the part of a FOR loop iteration scheme from FOR up to the -- loop_parameter_specification -- the part of a WHILE loop up to the condition -- the part of an extended_return_statement from RETURN up to the -- expression (if present) or to the return_subtype_indication (if -- no expression) -- and any pragma that occurs at a place where a statement or declaration -- is allowed. -- Statement lines -- These lines correspond to one or more successive statements (in the -- sense of the above list) which are always executed in sequence (in the -- absence of exceptions or other external interruptions). -- Entry points to such sequences are: -- the first declaration of any declarative_part -- the first statement of any sequence_of_statements that is not in a -- body or block statement that has a non-empty declarative part -- the first statement after a compound statement -- the first statement after an EXIT, RAISE or GOTO statement -- any statement with a label (the label itself is not part of the -- entry point that is recorded). -- Each entry point must appear as the first entry on a CS line. -- The idea is that if any simple statement on a CS line is known to have -- been executed, then all statements that appear before it on the same -- CS line are certain to also have been executed. -- The form of a statement line in the ALI file is: -- CS *sloc-range [*sloc-range...] -- where each sloc-range corresponds to a single statement, and * is -- one of: -- t type declaration -- s subtype declaration -- o object declaration -- r renaming declaration -- i generic instantiation -- C CASE statement (from CASE through end of expression) -- E EXIT statement -- F FOR loop statement (from FOR through end of iteration scheme) -- I IF statement (from IF through end of condition) -- P PRAGMA -- R extended RETURN statement -- W WHILE loop statement (from WHILE through end of condition) -- Note: for I and W, condition above is in the RM syntax sense (this -- condition is a decision in SCO terminology). -- and is omitted for all other cases -- Note: up to 6 entries can appear on a single CS line. If more than 6 -- entries appear in one logical statement sequence, continuation lines -- are marked by Cs and appear immediately after the CS line. -- Implementation permission: a SCO generator is permitted to emit a -- narrower SLOC range for a statement if the corresponding code -- generation circuitry ensures that all debug information for the code -- implementing the statement will be labeled with SLOCs that fall within -- that narrower range. -- Decisions -- Note: in the following description, logical operator includes only the -- short-circuited forms and NOT (so can be only NOT, AND THEN, OR ELSE). -- The reason that we can exclude AND/OR/XOR is that we expect SCO's to -- be generated using the restriction No_Direct_Boolean_Operators if we -- are interested in decision coverage, which does not permit the use of -- AND/OR/XOR on boolean operands. These are permitted on modular integer -- types, but such operations do not count as decisions in any case. If -- we are generating SCO's only for simple coverage, then we are not -- interested in decisions in any case. -- Note: the reason we include NOT is for informational purposes. The -- presence of NOT does not generate additional coverage obligations, -- but if we know where the NOT's are, the coverage tool can generate -- more accurate diagnostics on uncovered tests. -- A top level boolean expression is a boolean expression that is not an -- operand of a logical operator. -- Decisions are either simple or complex. A simple decision is a top -- level boolean expression that has only one condition and that occurs -- in the context of a control structure in the source program, including -- WHILE, IF, EXIT WHEN, or immediately within an Assert, Check, -- Pre_Condition or Post_Condition pragma, or as the first argument of a -- dyadic pragma Debug. Note that a top level boolean expression with -- only one condition that occurs in any other context, for example as -- right hand side of an assignment, is not considered to be a (simple) -- decision. -- A complex decision is a top level boolean expression that has more -- than one condition. A complex decision may occur in any boolean -- expression context. -- So for example, if we have -- A, B, C, D : Boolean; -- function F (Arg : Boolean) return Boolean); -- ... -- A and then (B or else F (C and then D)) -- There are two (complex) decisions here: -- 1. X and then (Y or else Z) -- where X = A, Y = B, and Z = F (C and then D) -- 2. C and then D -- For each decision, a decision line is generated with the form: -- C* sloc expression [chaining] -- Here * is one of the following characters: -- E decision in EXIT WHEN statement -- G decision in entry guard -- I decision in IF statement or conditional expression -- P decision in pragma Assert/Check/Pre_Condition/Post_Condition -- W decision in WHILE iteration scheme -- X decision appearing in some other expression context -- For E, G, I, P, W, sloc is the source location of the EXIT, ENTRY, IF, -- PRAGMA or WHILE token, respectively -- For X, sloc is omitted -- The expression is a prefix polish form indicating the structure of -- the decision, including logical operators and short-circuit forms. -- The following is a grammar showing the structure of expression: -- expression ::= term (if expr is not logical operator) -- expression ::= &sloc term term (if expr is AND or AND THEN) -- expression ::= |sloc term term (if expr is OR or OR ELSE) -- expression ::= !sloc term (if expr is NOT) -- In the last three cases, sloc is the source location of the AND, OR, -- or NOT token, respectively. -- term ::= element -- term ::= expression -- element ::= *sloc-range -- where * is one of the following letters: -- c condition -- t true condition -- f false condition -- t/f are used to mark a condition that has been recognized by the -- compiler as always being true or false. c is the normal case of -- conditions whose value is not known at compile time. -- & indicates AND THEN connecting two conditions -- | indicates OR ELSE connecting two conditions -- ! indicates NOT applied to the expression -- Note that complex decisions do NOT include non-short-circuited logical -- operators (AND/XOR/OR). In the context of existing coverage tools the -- No_Direct_Boolean_Operators restriction is assumed, so these operators -- cannot appear in the source in any case. -- The SCO line for a decision always occurs after the CS line for the -- enclosing statement. The SCO line for a nested decision always occurs -- after the line for the enclosing decision. -- Note that membership tests are considered to be a single simple -- condition, and that is true even if the Ada 2005 set membership -- form is used, e.g. A in (2,7,11.15). -- The expression can be followed by chaining indicators of the form -- Tsloc-range or Fsloc-range, where the sloc-range is that of some -- entry on a CS line. -- T* is present when the statement with the given sloc range is executed -- if, and only if, the decision evaluates to TRUE. -- F* is present when the statement with the given sloc range is executed -- if, and only if, the decision evaluates to FALSE. -- For an IF statement or ELSIF part, a T chaining indicator is always -- present, with the sloc range of the first statement in the -- corresponding sequence. -- For an ELSE part, the last decision in the IF statement (that of the -- last ELSIF part, if any, or that of the IF statement if there is no -- ELSIF part) has an F chaining indicator with the sloc range of the -- first statement in the sequence of the ELSE part. -- For a WHILE loop, a T chaining indicator is always present, with the -- sloc range of the first statement in the loop, but no F chaining -- indicator is ever present. -- For an EXIT WHEN statement, an F chaining indicator is present if -- there is an immediately following sequence in the same sequence of -- statements. -- In all other cases, chaining indicators are omitted -- Implementation permission: a SCO generator is permitted to emit a -- narrower SLOC range for a condition if the corresponding code -- generation circuitry ensures that all debug information for the code -- evaluating the condition will be labeled with SLOCs that fall within -- that narrower range. -- Case Expressions -- For case statements, we rely on statement coverage to make sure that -- all branches of a case statement are covered, but that does not work -- for case expressions, since the entire expression is contained in a -- single statement. However, for complete coverage we really should be -- able to check that every branch of the case statement is covered, so -- we generate a SCO of the form: -- CC sloc-range sloc-range ... -- where sloc-range covers the range of the case expression -- Note: up to 6 entries can appear on a single CC line. If more than 6 -- entries appear in one logical statement sequence, continuation lines -- are marked by Cc and appear immediately after the CC line. -- Disabled pragmas -- No SCO is generated for disabled pragmas --------------------------------------------------------------------- -- Internal table used to store Source Coverage Obligations (SCOs) -- --------------------------------------------------------------------- type Source_Location is record Line : Logical_Line_Number; Col : Column_Number; end record; No_Source_Location : Source_Location := (No_Line_Number, No_Column_Number); type SCO_Table_Entry is record From : Source_Location; To : Source_Location; C1 : Character; C2 : Character; Last : Boolean; Pragma_Sloc : Source_Ptr := No_Location; -- For the statement SCO for a pragma, or for any expression SCO nested -- in a pragma Debug/Assert/PPC, location of PRAGMA token (used for -- control of SCO output, value not recorded in ALI file). end record; package SCO_Table is new GNAT.Table ( Table_Component_Type => SCO_Table_Entry, Table_Index_Type => Nat, Table_Low_Bound => 1, Table_Initial => 500, Table_Increment => 300); -- The SCO_Table_Entry values appear as follows: -- Statements -- C1 = 'S' for entry point, 's' otherwise -- C2 = statement type code to appear on CS line (or ' ' if none) -- From = starting source location -- To = ending source location -- Last = False for all but the last entry, True for last entry -- Note: successive statements (possibly interspersed with entries of -- other kinds, that are ignored for this purpose), starting with one -- labeled with C1 = 'S', up to and including the first one labeled with -- Last = True, indicate the sequence to be output for a sequence of -- statements on a single CS line (possibly followed by Cs continuation -- lines). -- Note: for a pragma that may be disabled (Debug, Assert, PPC, Check), -- the entry is initially created with C2 = 'p', to mark it as disabled. -- Later on during semantic analysis, if the pragma is enabled, -- Set_SCO_Pragma_Enabled changes C2 to 'P' to cause the entry to be -- emitted in Put_SCOs. -- Decision (EXIT/entry guard/IF/WHILE) -- C1 = 'E'/'G'/'I'/'W' (for EXIT/entry Guard/IF/WHILE) -- C2 = ' ' -- From = EXIT/ENTRY/IF/WHILE token -- To = No_Source_Location -- Last = unused -- Decision (PRAGMA) -- C1 = 'P' -- C2 = ' ' -- From = PRAGMA token -- To = No_Source_Location -- Last = unused -- Note: when the parse tree is first scanned, we unconditionally build a -- pragma decision entry for any decision in a pragma (here as always in -- SCO contexts, the only pragmas with decisions are Assert, Check, -- dyadic Debug, Precondition and Postcondition). These entries will -- be omitted in output if the pragma is disabled (see comments for -- statement entries). -- Decision (Expression) -- C1 = 'X' -- C2 = ' ' -- From = No_Source_Location -- To = No_Source_Location -- Last = unused -- Operator -- C1 = '!', '&', '|' -- C2 = ' ' -- From = location of NOT/AND/OR token -- To = No_Source_Location -- Last = False -- Element (condition) -- C1 = ' ' -- C2 = 'c', 't', or 'f' (condition/true/false) -- From = starting source location -- To = ending source location -- Last = False for all but the last entry, True for last entry -- Element (chaining indicator) -- C1 = 'H' (cHain) -- C2 = 'T' or 'F' (chaining on decision true/false) -- From = starting source location of chained statement -- To = ending source location of chained statement -- Note: the sequence starting with a decision, and continuing with -- operators and elements up to and including the first one labeled with -- Last = True, indicate the sequence to be output on one decision line. ---------------- -- Unit Table -- ---------------- -- This table keeps track of the units and the corresponding starting and -- ending indexes (From, To) in the SCO table. Note that entry zero is -- unused, it is for convenience in calling the sort routine. Thus the -- real lower bound for active entries is 1. type SCO_Unit_Index is new Int; -- Used to index values in this table. Values start at 1 and are assigned -- sequentially as entries are constructed. type SCO_Unit_Table_Entry is record File_Name : String_Ptr; -- Pointer to file name in ALI file Dep_Num : Nat; -- Dependency number in ALI file From : Nat; -- Starting index in SCO_Table of SCO information for this unit To : Nat; -- Ending index in SCO_Table of SCO information for this unit end record; package SCO_Unit_Table is new GNAT.Table ( Table_Component_Type => SCO_Unit_Table_Entry, Table_Index_Type => SCO_Unit_Index, Table_Low_Bound => 0, -- see note above on sorting Table_Initial => 20, Table_Increment => 200); ----------------- -- Subprograms -- ----------------- procedure Initialize; -- Reset tables for a new compilation procedure Add_SCO (From : Source_Location := No_Source_Location; To : Source_Location := No_Source_Location; C1 : Character := ' '; C2 : Character := ' '; Last : Boolean := False; Pragma_Sloc : Source_Ptr := No_Location); -- Adds one entry to SCO table with given field values end SCOs;