1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 2009-2011, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 -- This package defines tables used to store Source Coverage Obligations. It
27 -- is used by Par_SCO to build the SCO information before writing it out to
28 -- the ALI file, and by Get_SCO/Put_SCO to read and write the text form that
29 -- is used in the ALI file.
31 with Types; use Types;
37 -- SCO information can exist in one of two forms. In the ALI file, it is
38 -- represented using a text format that is described in this specification.
39 -- Internally it is stored using two tables SCO_Table and SCO_Unit_Table,
40 -- which are also defined in this unit.
42 -- Par_SCO is part of the compiler. It scans the parsed source tree and
43 -- populates the internal tables.
45 -- Get_SCO reads the text lines in ALI format and populates the internal
46 -- tables with corresponding information.
48 -- Put_SCO reads the internal tables and generates text lines in the ALI
55 -- Source coverage obligations are generated on a unit-by-unit basis in the
56 -- ALI file, using lines that start with the identifying character C. These
57 -- lines are generated if the -gnateS switch is set.
61 -- In several places in the SCO lines, Sloc ranges appear. These are used
62 -- to indicate the first and last Sloc of some construct in the tree and
63 -- they have the form:
67 -- Note that SCO's are generated only for generic templates, not for
68 -- generic instances (since only the first are part of the source). So
69 -- we don't need generic instantiation stuff in these line:col items.
73 -- The SCO information follows the cross-reference information, so it
74 -- need not be read by tools like gnatbind, gnatmake etc. The SCO output
75 -- is divided into sections, one section for each unit for which SCO's
76 -- are generated. A SCO section has a header of the form:
78 -- C dependency-number filename
80 -- This header precedes SCO information for the unit identified by
81 -- dependency number and file name. The dependency number is the
82 -- index into the generated D lines and is ones origin (i.e. 2 =
83 -- reference to second generated D line).
85 -- Note that the filename here will reflect the original name if
86 -- a Source_Reference pragma was encountered (since all line number
87 -- references will be with respect to the original file).
89 -- Note: the filename is redundant in that it could be deduced from
90 -- the corresponding D line, but it is convenient at least for human
91 -- reading of the SCO information, and means that the SCO information
92 -- can stand on its own without needing other parts of the ALI file.
96 -- For the purpose of SCO generation, the notion of statement includes
97 -- simple statements and also the following declaration types:
100 -- subtype_declaration
101 -- object_declaration
102 -- renaming_declaration
103 -- generic_instantiation
105 -- and the following regions of the syntax tree:
107 -- the part of a case_statement from CASE up to the expression
108 -- the part of a FOR loop iteration scheme from FOR up to the
109 -- loop_parameter_specification
110 -- the part of a WHILE loop up to the condition
111 -- the part of an extended_return_statement from RETURN up to the
112 -- expression (if present) or to the return_subtype_indication (if
115 -- and any pragma that occurs at a place where a statement or declaration
120 -- These lines correspond to one or more successive statements (in the
121 -- sense of the above list) which are always executed in sequence (in the
122 -- absence of exceptions or other external interruptions).
124 -- Entry points to such sequences are:
126 -- the first declaration of any declarative_part
127 -- the first statement of any sequence_of_statements that is not in a
128 -- body or block statement that has a non-empty declarative part
129 -- the first statement after a compound statement
130 -- the first statement after an EXIT, RAISE or GOTO statement
131 -- any statement with a label (the label itself is not part of the
132 -- entry point that is recorded).
134 -- Each entry point must appear as the first entry on a CS line.
135 -- The idea is that if any simple statement on a CS line is known to have
136 -- been executed, then all statements that appear before it on the same
137 -- CS line are certain to also have been executed.
139 -- The form of a statement line in the ALI file is:
141 -- CS *sloc-range [*sloc-range...]
143 -- where each sloc-range corresponds to a single statement, and * is
146 -- t type declaration
147 -- s subtype declaration
148 -- o object declaration
149 -- r renaming declaration
150 -- i generic instantiation
151 -- C CASE statement (from CASE through end of expression)
153 -- F FOR loop statement (from FOR through end of iteration scheme)
154 -- I IF statement (from IF through end of condition)
156 -- R extended RETURN statement
157 -- W WHILE loop statement (from WHILE through end of condition)
159 -- Note: for I and W, condition above is in the RM syntax sense (this
160 -- condition is a decision in SCO terminology).
162 -- and is omitted for all other cases
164 -- Note: up to 6 entries can appear on a single CS line. If more than 6
165 -- entries appear in one logical statement sequence, continuation lines
166 -- are marked by Cs and appear immediately after the CS line.
168 -- Implementation permission: a SCO generator is permitted to emit a
169 -- narrower SLOC range for a statement if the corresponding code
170 -- generation circuitry ensures that all debug information for the code
171 -- implementing the statement will be labeled with SLOCs that fall within
172 -- that narrower range.
176 -- Note: in the following description, logical operator includes only the
177 -- short-circuited forms and NOT (so can be only NOT, AND THEN, OR ELSE).
178 -- The reason that we can exclude AND/OR/XOR is that we expect SCO's to
179 -- be generated using the restriction No_Direct_Boolean_Operators if we
180 -- are interested in decision coverage, which does not permit the use of
181 -- AND/OR/XOR on boolean operands. These are permitted on modular integer
182 -- types, but such operations do not count as decisions in any case. If
183 -- we are generating SCO's only for simple coverage, then we are not
184 -- interested in decisions in any case.
186 -- Note: the reason we include NOT is for informational purposes. The
187 -- presence of NOT does not generate additional coverage obligations,
188 -- but if we know where the NOT's are, the coverage tool can generate
189 -- more accurate diagnostics on uncovered tests.
191 -- A top level boolean expression is a boolean expression that is not an
192 -- operand of a logical operator.
194 -- Decisions are either simple or complex. A simple decision is a top
195 -- level boolean expression that has only one condition and that occurs
196 -- in the context of a control structure in the source program, including
197 -- WHILE, IF, EXIT WHEN, or immediately within an Assert, Check,
198 -- Pre_Condition or Post_Condition pragma, or as the first argument of a
199 -- dyadic pragma Debug. Note that a top level boolean expression with
200 -- only one condition that occurs in any other context, for example as
201 -- right hand side of an assignment, is not considered to be a (simple)
204 -- A complex decision is a top level boolean expression that has more
205 -- than one condition. A complex decision may occur in any boolean
206 -- expression context.
208 -- So for example, if we have
210 -- A, B, C, D : Boolean;
211 -- function F (Arg : Boolean) return Boolean);
213 -- A and then (B or else F (C and then D))
215 -- There are two (complex) decisions here:
217 -- 1. X and then (Y or else Z)
219 -- where X = A, Y = B, and Z = F (C and then D)
223 -- For each decision, a decision line is generated with the form:
225 -- C* sloc expression [chaining]
227 -- Here * is one of the following characters:
229 -- E decision in EXIT WHEN statement
230 -- G decision in entry guard
231 -- I decision in IF statement or conditional expression
232 -- P decision in pragma Assert/Check/Pre_Condition/Post_Condition
233 -- W decision in WHILE iteration scheme
234 -- X decision appearing in some other expression context
236 -- For E, G, I, P, W, sloc is the source location of the EXIT, ENTRY, IF,
237 -- PRAGMA or WHILE token, respectively
239 -- For X, sloc is omitted
241 -- The expression is a prefix polish form indicating the structure of
242 -- the decision, including logical operators and short-circuit forms.
243 -- The following is a grammar showing the structure of expression:
245 -- expression ::= term (if expr is not logical operator)
246 -- expression ::= &sloc term term (if expr is AND or AND THEN)
247 -- expression ::= |sloc term term (if expr is OR or OR ELSE)
248 -- expression ::= !sloc term (if expr is NOT)
250 -- In the last three cases, sloc is the source location of the AND, OR,
251 -- or NOT token, respectively.
254 -- term ::= expression
256 -- element ::= *sloc-range
258 -- where * is one of the following letters:
264 -- t/f are used to mark a condition that has been recognized by the
265 -- compiler as always being true or false. c is the normal case of
266 -- conditions whose value is not known at compile time.
268 -- & indicates AND THEN connecting two conditions
270 -- | indicates OR ELSE connecting two conditions
272 -- ! indicates NOT applied to the expression
274 -- Note that complex decisions do NOT include non-short-circuited logical
275 -- operators (AND/XOR/OR). In the context of existing coverage tools the
276 -- No_Direct_Boolean_Operators restriction is assumed, so these operators
277 -- cannot appear in the source in any case.
279 -- The SCO line for a decision always occurs after the CS line for the
280 -- enclosing statement. The SCO line for a nested decision always occurs
281 -- after the line for the enclosing decision.
283 -- Note that membership tests are considered to be a single simple
284 -- condition, and that is true even if the Ada 2005 set membership
285 -- form is used, e.g. A in (2,7,11.15).
287 -- The expression can be followed by chaining indicators of the form
288 -- Tsloc-range or Fsloc-range, where the sloc-range is that of some
289 -- entry on a CS line.
291 -- T* is present when the statement with the given sloc range is executed
292 -- if, and only if, the decision evaluates to TRUE.
294 -- F* is present when the statement with the given sloc range is executed
295 -- if, and only if, the decision evaluates to FALSE.
297 -- For an IF statement or ELSIF part, a T chaining indicator is always
298 -- present, with the sloc range of the first statement in the
299 -- corresponding sequence.
301 -- For an ELSE part, the last decision in the IF statement (that of the
302 -- last ELSIF part, if any, or that of the IF statement if there is no
303 -- ELSIF part) has an F chaining indicator with the sloc range of the
304 -- first statement in the sequence of the ELSE part.
306 -- For a WHILE loop, a T chaining indicator is always present, with the
307 -- sloc range of the first statement in the loop, but no F chaining
308 -- indicator is ever present.
310 -- For an EXIT WHEN statement, an F chaining indicator is present if
311 -- there is an immediately following sequence in the same sequence of
314 -- In all other cases, chaining indicators are omitted
316 -- Implementation permission: a SCO generator is permitted to emit a
317 -- narrower SLOC range for a condition if the corresponding code
318 -- generation circuitry ensures that all debug information for the code
319 -- evaluating the condition will be labeled with SLOCs that fall within
320 -- that narrower range.
324 -- For case statements, we rely on statement coverage to make sure that
325 -- all branches of a case statement are covered, but that does not work
326 -- for case expressions, since the entire expression is contained in a
327 -- single statement. However, for complete coverage we really should be
328 -- able to check that every branch of the case statement is covered, so
329 -- we generate a SCO of the form:
331 -- CC sloc-range sloc-range ...
333 -- where sloc-range covers the range of the case expression
335 -- Note: up to 6 entries can appear on a single CC line. If more than 6
336 -- entries appear in one logical statement sequence, continuation lines
337 -- are marked by Cc and appear immediately after the CC line.
341 -- No SCO is generated for disabled pragmas
343 ---------------------------------------------------------------------
344 -- Internal table used to store Source Coverage Obligations (SCOs) --
345 ---------------------------------------------------------------------
347 type Source_Location is record
348 Line : Logical_Line_Number;
352 No_Source_Location : Source_Location := (No_Line_Number, No_Column_Number);
354 type SCO_Table_Entry is record
355 From : Source_Location;
356 To : Source_Location;
361 Pragma_Sloc : Source_Ptr := No_Location;
362 -- For the statement SCO for a pragma, or for any expression SCO nested
363 -- in a pragma Debug/Assert/PPC, location of PRAGMA token (used for
364 -- control of SCO output, value not recorded in ALI file).
367 package SCO_Table is new GNAT.Table (
368 Table_Component_Type => SCO_Table_Entry,
369 Table_Index_Type => Nat,
370 Table_Low_Bound => 1,
371 Table_Initial => 500,
372 Table_Increment => 300);
374 -- The SCO_Table_Entry values appear as follows:
377 -- C1 = 'S' for entry point, 's' otherwise
378 -- C2 = statement type code to appear on CS line (or ' ' if none)
379 -- From = starting source location
380 -- To = ending source location
381 -- Last = False for all but the last entry, True for last entry
383 -- Note: successive statements (possibly interspersed with entries of
384 -- other kinds, that are ignored for this purpose), starting with one
385 -- labeled with C1 = 'S', up to and including the first one labeled with
386 -- Last = True, indicate the sequence to be output for a sequence of
387 -- statements on a single CS line (possibly followed by Cs continuation
390 -- Note: for a pragma that may be disabled (Debug, Assert, PPC, Check),
391 -- the entry is initially created with C2 = 'p', to mark it as disabled.
392 -- Later on during semantic analysis, if the pragma is enabled,
393 -- Set_SCO_Pragma_Enabled changes C2 to 'P' to cause the entry to be
394 -- emitted in Put_SCOs.
396 -- Decision (EXIT/entry guard/IF/WHILE)
397 -- C1 = 'E'/'G'/'I'/'W' (for EXIT/entry Guard/IF/WHILE)
399 -- From = EXIT/ENTRY/IF/WHILE token
400 -- To = No_Source_Location
406 -- From = PRAGMA token
407 -- To = No_Source_Location
410 -- Note: when the parse tree is first scanned, we unconditionally build a
411 -- pragma decision entry for any decision in a pragma (here as always in
412 -- SCO contexts, the only pragmas with decisions are Assert, Check,
413 -- dyadic Debug, Precondition and Postcondition). These entries will
414 -- be omitted in output if the pragma is disabled (see comments for
415 -- statement entries).
417 -- Decision (Expression)
420 -- From = No_Source_Location
421 -- To = No_Source_Location
425 -- C1 = '!', '&', '|'
427 -- From = location of NOT/AND/OR token
428 -- To = No_Source_Location
431 -- Element (condition)
433 -- C2 = 'c', 't', or 'f' (condition/true/false)
434 -- From = starting source location
435 -- To = ending source location
436 -- Last = False for all but the last entry, True for last entry
438 -- Element (chaining indicator)
440 -- C2 = 'T' or 'F' (chaining on decision true/false)
441 -- From = starting source location of chained statement
442 -- To = ending source location of chained statement
444 -- Note: the sequence starting with a decision, and continuing with
445 -- operators and elements up to and including the first one labeled with
446 -- Last = True, indicate the sequence to be output on one decision line.
452 -- This table keeps track of the units and the corresponding starting and
453 -- ending indexes (From, To) in the SCO table. Note that entry zero is
454 -- unused, it is for convenience in calling the sort routine. Thus the
455 -- real lower bound for active entries is 1.
457 type SCO_Unit_Index is new Int;
458 -- Used to index values in this table. Values start at 1 and are assigned
459 -- sequentially as entries are constructed.
461 type SCO_Unit_Table_Entry is record
462 File_Name : String_Ptr;
463 -- Pointer to file name in ALI file
466 -- Dependency number in ALI file
469 -- Starting index in SCO_Table of SCO information for this unit
472 -- Ending index in SCO_Table of SCO information for this unit
475 package SCO_Unit_Table is new GNAT.Table (
476 Table_Component_Type => SCO_Unit_Table_Entry,
477 Table_Index_Type => SCO_Unit_Index,
478 Table_Low_Bound => 0, -- see note above on sorting
480 Table_Increment => 200);
486 procedure Initialize;
487 -- Reset tables for a new compilation
490 (From : Source_Location := No_Source_Location;
491 To : Source_Location := No_Source_Location;
492 C1 : Character := ' ';
493 C2 : Character := ' ';
494 Last : Boolean := False;
495 Pragma_Sloc : Source_Ptr := No_Location);
496 -- Adds one entry to SCO table with given field values