scanner: don't accept invalid symbols in binary expressions

The rules for binary expressions were entirely oblivious to the type of
the operand symbols and assumed they're integer constants.

This is very unfortunate, since it caused all sort of nonsense to end up
getting accepted. One such example is the following define from
NetworkManager's libnm:

  #define NM_SETTING_PARAM_SECRET (1 << (2 + G_PARAM_USER_SHIFT))

As G_PARAM_USER_SHIFT is unknown, it was parsed as an invalid symbol.
The addition didn't care, treated it as:

  #define NM_SETTING_PARAM_SECRET (1 << (2 + 0))

Let's just ensure we get CSYMBOL_TYPE_CONST only when both operands
actually have const_int_set. Otherwise just create CSYMBOL_TYPE_INVALID.
That will cause the symbol to be dropped on the floor eventually, but
that's probably much better than a having an invalid value.

7 files changed, 41 insertions, 84 deletions

diff --git a/giscanner/scannerparser.y b/giscanner/scannerparser.y
index 52fc1996..26c9eba7 100644
--- a/giscanner/scannerparser.y
+++ b/giscanner/scannerparser.y
@@ -582,24 +582,25 @@ multiplicative_expression
 	: cast_expression
 	| multiplicative_expression '*' cast_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int * $3->const_int;
 	  }
 	| multiplicative_expression '/' cast_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
 		if ($3->const_int != 0) {
+			$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 			$$->const_int = $1->const_int / $3->const_int;
+		} else {
+			$$ = gi_source_symbol_new (CSYMBOL_TYPE_INVALID, scanner->current_file, lineno);
 		}
 	  }
 	| multiplicative_expression '%' cast_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
 		if ($3->const_int != 0) {
+			$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 			$$->const_int = $1->const_int % $3->const_int;
+		} else {
+			$$ = gi_source_symbol_new (CSYMBOL_TYPE_INVALID, scanner->current_file, lineno);
 		}
 	  }
 	;
@@ -608,14 +609,12 @@ additive_expression
 	: multiplicative_expression
 	| additive_expression '+' multiplicative_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int + $3->const_int;
 	  }
 	| additive_expression '-' multiplicative_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int - $3->const_int;
 	  }
 	;
@@ -624,8 +623,7 @@ shift_expression
 	: additive_expression
 	| shift_expression SL additive_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int << $3->const_int;
 
 		/* assume this is a bitfield/flags declaration
@@ -636,8 +634,7 @@ shift_expression
 	  }
 	| shift_expression SR additive_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int >> $3->const_int;
 	  }
 	;
@@ -646,26 +643,22 @@ relational_expression
 	: shift_expression
 	| relational_expression '<' shift_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int < $3->const_int;
 	  }
 	| relational_expression '>' shift_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int > $3->const_int;
 	  }
 	| relational_expression LTEQ shift_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int <= $3->const_int;
 	  }
 	| relational_expression GTEQ shift_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int >= $3->const_int;
 	  }
 	;
@@ -674,14 +667,12 @@ equality_expression
 	: relational_expression
 	| equality_expression EQ relational_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int == $3->const_int;
 	  }
 	| equality_expression NOTEQ relational_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int != $3->const_int;
 	  }
 	;
@@ -690,8 +681,7 @@ and_expression
 	: equality_expression
 	| and_expression '&' equality_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int & $3->const_int;
 	  }
 	;
@@ -700,8 +690,7 @@ exclusive_or_expression
 	: and_expression
 	| exclusive_or_expression '^' and_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int ^ $3->const_int;
 	  }
 	;
@@ -710,8 +699,7 @@ inclusive_or_expression
 	: exclusive_or_expression
 	| inclusive_or_expression '|' exclusive_or_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int = $1->const_int | $3->const_int;
 	  }
 	;
@@ -720,8 +708,7 @@ logical_and_expression
 	: inclusive_or_expression
 	| logical_and_expression ANDAND inclusive_or_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int =
 		  gi_source_symbol_get_const_boolean ($1) &&
 		  gi_source_symbol_get_const_boolean ($3);
@@ -732,8 +719,7 @@ logical_or_expression
 	: logical_and_expression
 	| logical_or_expression OROR logical_and_expression
 	  {
-		$$ = gi_source_symbol_new (CSYMBOL_TYPE_CONST, scanner->current_file, lineno);
-		$$->const_int_set = TRUE;
+		$$ = gi_source_symbol_const_binary ($1, $3, scanner->current_file, lineno);
 		$$->const_int =
 		  gi_source_symbol_get_const_boolean ($1) ||
 		  gi_source_symbol_get_const_boolean ($3);
diff --git a/giscanner/sourcescanner.c b/giscanner/sourcescanner.c
index 27f82f77..80c61a27 100644
--- a/giscanner/sourcescanner.c
+++ b/giscanner/sourcescanner.c
@@ -74,6 +74,21 @@ gi_source_symbol_copy (GISourceSymbol * symbol)
 }
 
 GISourceSymbol *
+gi_source_symbol_const_binary (GISourceSymbol * s1, GISourceSymbol * s2, GFile *file, int line)
+{
+  GISourceSymbol *new_symbol;
+
+  if (s1->const_int_set && s2->const_int_set) {
+    new_symbol = gi_source_symbol_new (CSYMBOL_TYPE_CONST, file, line);
+    new_symbol->const_int_set = TRUE;
+  } else {
+    new_symbol = gi_source_symbol_new (CSYMBOL_TYPE_INVALID, file, line);
+  }
+
+  return new_symbol;
+}
+
+GISourceSymbol *
 gi_source_symbol_ref (GISourceSymbol * symbol)
 {
   symbol->ref_count++;
diff --git a/giscanner/sourcescanner.h b/giscanner/sourcescanner.h
index 40c5fc96..eb2d312f 100644
--- a/giscanner/sourcescanner.h
+++ b/giscanner/sourcescanner.h
@@ -172,6 +172,10 @@ gboolean            gi_source_symbol_get_const_boolean (GISourceSymbol     *symb
 GISourceSymbol *    gi_source_symbol_ref               (GISourceSymbol     *symbol);
 void                gi_source_symbol_unref             (GISourceSymbol     *symbol);
 GISourceSymbol *    gi_source_symbol_copy              (GISourceSymbol     *symbol);
+GISourceSymbol *    gi_source_symbol_const_binary      (GISourceSymbol     *s1,
+                                                        GISourceSymbol     *s2,
+                                                        GFile              *file,
+                                                        int                 line);
 
 /* Private */
 void                gi_source_scanner_add_symbol       (GISourceScanner  *scanner,
diff --git a/tests/scanner/Regress-1.0-C-expected/Regress.BAD_EXPR_CONSTANT.page b/tests/scanner/Regress-1.0-C-expected/Regress.BAD_EXPR_CONSTANT.page
deleted file mode 100644
index bc8190a8..00000000
--- a/tests/scanner/Regress-1.0-C-expected/Regress.BAD_EXPR_CONSTANT.page
+++ /dev/null
@@ -1,14 +0,0 @@
-<?xml version="1.0"?>
-<page id="Regress.BAD_EXPR_CONSTANT"
-      type="topic"
-      style="default"
-      xmlns="http://projectmallard.org/1.0/"
-      xmlns:api="http://projectmallard.org/experimental/api/"
-      xmlns:ui="http://projectmallard.org/1.0/ui/">
-  <info>
-    <link xref="index" group="default" type="guide"/>
-  </info>
-  <title>Regress.BAD_EXPR_CONSTANT</title>
-
-
-</page>
diff --git a/tests/scanner/Regress-1.0-Gjs-expected/Regress.BAD_EXPR_CONSTANT.page b/tests/scanner/Regress-1.0-Gjs-expected/Regress.BAD_EXPR_CONSTANT.page
deleted file mode 100644
index bc8190a8..00000000
--- a/tests/scanner/Regress-1.0-Gjs-expected/Regress.BAD_EXPR_CONSTANT.page
+++ /dev/null
@@ -1,14 +0,0 @@
-<?xml version="1.0"?>
-<page id="Regress.BAD_EXPR_CONSTANT"
-      type="topic"
-      style="default"
-      xmlns="http://projectmallard.org/1.0/"
-      xmlns:api="http://projectmallard.org/experimental/api/"
-      xmlns:ui="http://projectmallard.org/1.0/ui/">
-  <info>
-    <link xref="index" group="default" type="guide"/>
-  </info>
-  <title>Regress.BAD_EXPR_CONSTANT</title>
-
-
-</page>
diff --git a/tests/scanner/Regress-1.0-Python-expected/Regress.BAD_EXPR_CONSTANT.page b/tests/scanner/Regress-1.0-Python-expected/Regress.BAD_EXPR_CONSTANT.page
deleted file mode 100644
index bc8190a8..00000000
--- a/tests/scanner/Regress-1.0-Python-expected/Regress.BAD_EXPR_CONSTANT.page
+++ /dev/null
@@ -1,14 +0,0 @@
-<?xml version="1.0"?>
-<page id="Regress.BAD_EXPR_CONSTANT"
-      type="topic"
-      style="default"
-      xmlns="http://projectmallard.org/1.0/"
-      xmlns:api="http://projectmallard.org/experimental/api/"
-      xmlns:ui="http://projectmallard.org/1.0/ui/">
-  <info>
-    <link xref="index" group="default" type="guide"/>
-  </info>
-  <title>Regress.BAD_EXPR_CONSTANT</title>
-
-
-</page>
diff --git a/tests/scanner/Regress-1.0-expected.gir b/tests/scanner/Regress-1.0-expected.gir
index b986c72f..079405d2 100644
--- a/tests/scanner/Regress-1.0-expected.gir
+++ b/tests/scanner/Regress-1.0-expected.gir
@@ -1248,12 +1248,6 @@ it says it's pointer but it's actually a string.</doc>
         </field>
       </union>
     </record>
-    <constant name="BAD_EXPR_CONSTANT"
-              value="1"
-              c:type="REGRESS_BAD_EXPR_CONSTANT">
-      <source-position filename="regress.h" line="528"/>
-      <type name="gint" c:type="gint"/>
-    </constant>
     <constant name="BOOL_CONSTANT" value="true" c:type="REGRESS_BOOL_CONSTANT">
       <source-position filename="regress.h" line="524"/>
       <type name="gboolean" c:type="gboolean"/>