Fix #235: Pragma displacing real statements (#236)
* Fix #235: Pragma displacing real statements
diff --git a/pycparser/c_parser.py b/pycparser/c_parser.py
index f01f67f..47d958f 100644
--- a/pycparser/c_parser.py
+++ b/pycparser/c_parser.py
@@ -616,6 +616,59 @@
"""
p[0] = p[1]
+ # A pragma is generally considered a decorator rather than an actual statement.
+ # Still, for the purposes of analyzing an abstract syntax tree of C code,
+ # pragma's should not be ignored and were previously treated as a statement.
+ # This presents a problem for constructs that take a statement such as labeled_statements,
+ # selection_statements, and iteration_statements, causing a misleading structure
+ # in the AST. For example, consider the following C code.
+ #
+ # for (int i = 0; i < 3; i++)
+ # #pragma omp critical
+ # sum += 1;
+ #
+ # This code will compile and execute "sum += 1;" as the body of the for loop.
+ # Previous implementations of PyCParser would render the AST for this
+ # block of code as follows:
+ #
+ # For:
+ # DeclList:
+ # Decl: i, [], [], []
+ # TypeDecl: i, []
+ # IdentifierType: ['int']
+ # Constant: int, 0
+ # BinaryOp: <
+ # ID: i
+ # Constant: int, 3
+ # UnaryOp: p++
+ # ID: i
+ # Pragma: omp critical
+ # Assignment: +=
+ # ID: sum
+ # Constant: int, 1
+ #
+ # This AST misleadingly takes the Pragma as the body of the loop and the
+ # assignment then becomes a sibling of the loop.
+ #
+ # To solve edge cases like these, the pragmacomp_or_statement rule groups
+ # a pragma and its following statement (which would otherwise be orphaned)
+ # using a compound block, effectively turning the above code into:
+ #
+ # for (int i = 0; i < 3; i++) {
+ # #pragma omp critical
+ # sum += 1;
+ # }
+ def p_pragmacomp_or_statement(self, p):
+ """ pragmacomp_or_statement : pppragma_directive statement
+ | statement
+ """
+ if isinstance(p[1], c_ast.Pragma) and len(p) == 3:
+ p[0] = c_ast.Compound(
+ block_items=[p[1], p[2]],
+ coord=self._token_coord(p, 1))
+ else:
+ p[0] = p[1]
+
# In C, declarations can come several in a line:
# int x, *px, romulo = 5;
#
@@ -1410,44 +1463,44 @@
coord=self._token_coord(p, 1))
def p_labeled_statement_1(self, p):
- """ labeled_statement : ID COLON statement """
+ """ labeled_statement : ID COLON pragmacomp_or_statement """
p[0] = c_ast.Label(p[1], p[3], self._token_coord(p, 1))
def p_labeled_statement_2(self, p):
- """ labeled_statement : CASE constant_expression COLON statement """
+ """ labeled_statement : CASE constant_expression COLON pragmacomp_or_statement """
p[0] = c_ast.Case(p[2], [p[4]], self._token_coord(p, 1))
def p_labeled_statement_3(self, p):
- """ labeled_statement : DEFAULT COLON statement """
+ """ labeled_statement : DEFAULT COLON pragmacomp_or_statement """
p[0] = c_ast.Default([p[3]], self._token_coord(p, 1))
def p_selection_statement_1(self, p):
- """ selection_statement : IF LPAREN expression RPAREN statement """
+ """ selection_statement : IF LPAREN expression RPAREN pragmacomp_or_statement """
p[0] = c_ast.If(p[3], p[5], None, self._token_coord(p, 1))
def p_selection_statement_2(self, p):
- """ selection_statement : IF LPAREN expression RPAREN statement ELSE statement """
+ """ selection_statement : IF LPAREN expression RPAREN statement ELSE pragmacomp_or_statement """
p[0] = c_ast.If(p[3], p[5], p[7], self._token_coord(p, 1))
def p_selection_statement_3(self, p):
- """ selection_statement : SWITCH LPAREN expression RPAREN statement """
+ """ selection_statement : SWITCH LPAREN expression RPAREN pragmacomp_or_statement """
p[0] = fix_switch_cases(
c_ast.Switch(p[3], p[5], self._token_coord(p, 1)))
def p_iteration_statement_1(self, p):
- """ iteration_statement : WHILE LPAREN expression RPAREN statement """
+ """ iteration_statement : WHILE LPAREN expression RPAREN pragmacomp_or_statement """
p[0] = c_ast.While(p[3], p[5], self._token_coord(p, 1))
def p_iteration_statement_2(self, p):
- """ iteration_statement : DO statement WHILE LPAREN expression RPAREN SEMI """
+ """ iteration_statement : DO pragmacomp_or_statement WHILE LPAREN expression RPAREN SEMI """
p[0] = c_ast.DoWhile(p[5], p[2], self._token_coord(p, 1))
def p_iteration_statement_3(self, p):
- """ iteration_statement : FOR LPAREN expression_opt SEMI expression_opt SEMI expression_opt RPAREN statement """
+ """ iteration_statement : FOR LPAREN expression_opt SEMI expression_opt SEMI expression_opt RPAREN pragmacomp_or_statement """
p[0] = c_ast.For(p[3], p[5], p[7], p[9], self._token_coord(p, 1))
def p_iteration_statement_4(self, p):
- """ iteration_statement : FOR LPAREN declaration expression_opt SEMI expression_opt RPAREN statement """
+ """ iteration_statement : FOR LPAREN declaration expression_opt SEMI expression_opt RPAREN pragmacomp_or_statement """
p[0] = c_ast.For(c_ast.DeclList(p[3], self._token_coord(p, 1)),
p[4], p[6], p[8], self._token_coord(p, 1))
diff --git a/tests/test_c_parser.py b/tests/test_c_parser.py
index ab6143f..3b336bf 100755
--- a/tests/test_c_parser.py
+++ b/tests/test_c_parser.py
@@ -1369,6 +1369,54 @@
self.assertEqual(s1_ast.ext[2].type.type.decls[0].string, 'baz')
self.assertEqual(s1_ast.ext[2].type.type.decls[0].coord.line, 9)
+ def test_pragmacomp_or_statement(self):
+ s1 = r'''
+ void main() {
+ int sum = 0;
+ for (int i; i < 3; i++)
+ #pragma omp critical
+ sum += 1;
+
+ while(sum < 10)
+ #pragma omp critical
+ sum += 1;
+
+ mylabel:
+ #pragma foo
+ sum += 10;
+
+ if (sum > 10)
+ #pragma bar
+ sum = 10;
+
+ switch (sum)
+ case 10:
+ #pragma foo
+ sum = 20;
+ }
+ '''
+ s1_ast = self.parse(s1)
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[1], For))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[1].stmt, Compound))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[1].stmt.block_items[0], Pragma))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[1].stmt.block_items[1], Assignment))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[2], While))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[2].stmt, Compound))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[2].stmt.block_items[0], Pragma))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[2].stmt.block_items[1], Assignment))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[3], Label))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[3].stmt, Compound))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[3].stmt.block_items[0], Pragma))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[3].stmt.block_items[1], Assignment))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[4], If))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[4].iftrue, Compound))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[4].iftrue.block_items[0], Pragma))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[4].iftrue.block_items[1], Assignment))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[5], Switch))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[5].stmt.stmts[0], Compound))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[5].stmt.stmts[0].block_items[0], Pragma))
+ self.assertTrue(isinstance(s1_ast.ext[0].body.block_items[5].stmt.stmts[0].block_items[1], Assignment))
+
class TestCParser_whole_code(TestCParser_base):
""" Testing of parsing whole chunks of code.
