diff mbox series

Fix valgrind error in "has_include" (PR preprocessor/88937)

Message ID 1549333123-35908-1-git-send-email-dmalcolm@redhat.com
State New
Headers show
Series Fix valgrind error in "has_include" (PR preprocessor/88937) | expand

Commit Message

David Malcolm Feb. 5, 2019, 2:18 a.m. UTC 
PR preprocessor/88937 reports a valgrind error:
 "Conditional jump or move depends on uninitialised value(s)"
when compiling:

  #if __has_include("x")
  #endif

The issue is in parse_has_include, which has:

  2211    if (token->type == CPP_STRING || token->type == CPP_HEADER_NAME)
  2212      {
  [..]    [...]
  2218        node = token->val.node.node;
  2219      }
  [..]    [...]
  2245    /* A possible controlling macro of the form #if !__has_include__ ().
  2246       _cpp_parse_expr checks there was no other junk on the line.  */
  2247    if (node)
  2248      pfile->mi_ind_cmacro = node;

token->val.node is the wrong member of the union cpp_token_u for
CPP_STRING and CPP_HEADER_NAME.  Line 2218 is effectively casting the
unsigned int len of the cpp_string to a cpp_hashnode *; line 2248 then
stores this bogus "pointer".

It looks like this is a copy&paste error, as there is similar-looking
code in parse_defined (where the comment makes sense).

This patch removes the erroneous-looking code from parse_has_include.

Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu; I've
verified that this fixes the valgrind issue.

This isn't a regression relative to the active branches (it's been in
the source since gcc 5), and I haven't been able to turn the reproducer
into a crasher.

I believe I can self-approve this for gcc 10.

libcpp/ChangeLog:
	PR preprocessor/88937
	* expr.c (parse_has_include): Remove "node" code copied from
	parse_defined.
---
 libcpp/expr.c | 7 -------
 1 file changed, 7 deletions(-)
diff mbox series

Patch

diff --git a/libcpp/expr.c b/libcpp/expr.c
index 6ab5493..1fcb98d 100644
--- a/libcpp/expr.c
+++ b/libcpp/expr.c
@@ -2189,7 +2189,6 @@  parse_has_include (cpp_reader *pfile, enum include_type type)
 {
   cpp_num result;
   bool paren = false;
-  cpp_hashnode *node = 0;
   const cpp_token *token;
   bool bracket = false;
   char *fname = 0;
@@ -2215,7 +2214,6 @@  parse_has_include (cpp_reader *pfile, enum include_type type)
       fname = XNEWVEC (char, token->val.str.len - 1);
       memcpy (fname, token->val.str.text + 1, token->val.str.len - 2);
       fname[token->val.str.len - 2] = '\0';
-      node = token->val.node.node;
     }
   else if (token->type == CPP_LESS)
     {
@@ -2242,11 +2240,6 @@  parse_has_include (cpp_reader *pfile, enum include_type type)
     cpp_error (pfile, CPP_DL_ERROR,
 	       "missing ')' after \"__has_include__\"");
 
-  /* A possible controlling macro of the form #if !__has_include__ ().
-     _cpp_parse_expr checks there was no other junk on the line.  */
-  if (node)
-    pfile->mi_ind_cmacro = node;
-
   pfile->state.in__has_include__--;
 
   return result;