[PING^3] Re: [PATCH] c/c++: Add fix-it hints for suggested missing #includes

David Malcolm dmalcolm@redhat.com
Tue Jun 27 16:47:00 GMT 2017


Ping re:

  https://gcc.gnu.org/ml/gcc-patches/2017-05/msg00321.html

On Tue, 2017-06-20 at 15:32 -0400, David Malcolm wrote:
> Ping re:
> 
>   https://gcc.gnu.org/ml/gcc-patches/2017-05/msg00321.html
> 
> 
> On Fri, 2017-05-26 at 15:54 -0400, David Malcolm wrote:
> > Ping:
> >   https://gcc.gnu.org/ml/gcc-patches/2017-05/msg00321.html
> > 
> > On Thu, 2017-05-04 at 12:36 -0400, David Malcolm wrote:
> > > As of r247522, fix-it-hints can suggest the insertion of new
> > > lines.
> > > 
> > > This patch uses this to implement a new "maybe_add_include_fixit"
> > > function in c-common.c and uses it in the two places where the C
> > > and
> > > C++
> > > frontend can suggest missing #include directives. [1]
> > > 
> > > The idea is that the user can then click on the fix-it in an IDE
> > > and have it add the #include for them (or use -fdiagnostics
> > > -generate
> > > -patch).
> > > 
> > > Examples can be seen in the test cases.
> > > 
> > > The function attempts to put the #include in a reasonable place:
> > > immediately after the last #include within the file, or at the
> > > top of the file.  It is idempotent, so -fdiagnostics-generate
> > > -patch
> > > does the right thing if several such diagnostics are emitted.
> > > 
> > > Successfully bootstrapped&regrtested on x86_64-pc-linux-gnu.
> > > 
> > > OK for trunk?
> > > 
> > > [1] I'm working on a followup which tweaks another diagnostic so
> > > that
> > > it
> > > can suggest that a #include was missing, so I'll use it there as
> > > well.
> > > 
> > > gcc/c-family/ChangeLog:
> > > 	* c-common.c (try_to_locate_new_include_insertion_point): New
> > > 	function.
> > > 	(per_file_includes_t): New typedef.
> > > 	(added_includes_t): New typedef.
> > > 	(added_includes): New variable.
> > > 	(maybe_add_include_fixit): New function.
> > > 	* c-common.h (maybe_add_include_fixit): New decl.
> > > 
> > > gcc/c/ChangeLog:
> > > 	* c-decl.c (implicitly_declare): When suggesting a missing
> > > 	#include, provide a fix-it hint.
> > > 
> > > gcc/cp/ChangeLog:
> > > 	* name-lookup.c (get_std_name_hint): Add '<' and '>' around
> > > 	the header names.
> > > 	(maybe_suggest_missing_header): Update for addition of '<' and
> > > '>'
> > > 	to above.  Provide a fix-it hint.
> > > 
> > > gcc/testsuite/ChangeLog:
> > > 	* g++.dg/lookup/missing-std-include-2.C: New text case.
> > > 	* gcc.dg/missing-header-fixit-1.c: New test case.
> > > ---
> > >  gcc/c-family/c-common.c                            | 117
> > > +++++++++++++++++++++
> > >  gcc/c-family/c-common.h                            |   2 +
> > >  gcc/c/c-decl.c                                     |  10 +-
> > >  gcc/cp/name-lookup.c                               |  94
> > > +++++++++
> > > --
> > > ------
> > >  .../g++.dg/lookup/missing-std-include-2.C          |  55
> > > ++++++++++
> > >  gcc/testsuite/gcc.dg/missing-header-fixit-1.c      |  36 +++++++
> > >  6 files changed, 267 insertions(+), 47 deletions(-)
> > >  create mode 100644 gcc/testsuite/g++.dg/lookup/missing-std
> > > -include
> > > -2.C
> > >  create mode 100644 gcc/testsuite/gcc.dg/missing-header-fixit-1.c
> > > 
> > > diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
> > > index 0884922..19f7e60 100644
> > > --- a/gcc/c-family/c-common.c
> > > +++ b/gcc/c-family/c-common.c
> > > @@ -7983,4 +7983,121 @@ c_flt_eval_method (bool maybe_c11_only_p)
> > >      return c_ts18661_flt_eval_method ();
> > >  }
> > >  
> > > +/* Attempt to locate a suitable location within FILE for a
> > > +   #include directive to be inserted before.  FILE should
> > > +   be a string from libcpp (pointer equality is used).
> > > +
> > > +   Attempt to return the location within FILE immediately
> > > +   after the last #include within that file, or the start of
> > > +   that file if it has no #include directives.
> > > +
> > > +   Return UNKNOWN_LOCATION if no suitable location is found,
> > > +   or if an error occurs.  */
> > > +
> > > +static location_t
> > > +try_to_locate_new_include_insertion_point (const char *file)
> > > +{
> > > +  /* Locate the last ordinary map within FILE that ended with a
> > > #include.  */
> > > +  const line_map_ordinary *last_include_ord_map = NULL;
> > > +
> > > +  /* ...and the next ordinary map within FILE after that one. 
> > >  */
> > > +  const line_map_ordinary *last_ord_map_after_include = NULL;
> > > +
> > > +  /* ...and the first ordinary map within FILE.  */
> > > +  const line_map_ordinary *first_ord_map_in_file = NULL;
> > > +
> > > +  for (unsigned int i = 0; i < LINEMAPS_ORDINARY_USED
> > > (line_table);
> > > i++)
> > > +    {
> > > +      const line_map_ordinary *ord_map
> > > +	= LINEMAPS_ORDINARY_MAP_AT (line_table, i);
> > > +
> > > +      const line_map_ordinary *from = INCLUDED_FROM (line_table,
> > > ord_map);
> > > +      if (from)
> > > +	if (from->to_file == file)
> > > +	  {
> > > +	    last_include_ord_map = from;
> > > +	    last_ord_map_after_include = NULL;
> > > +	  }
> > > +
> > > +      if (ord_map->to_file == file)
> > > +	{
> > > +	  if (!first_ord_map_in_file)
> > > +	    first_ord_map_in_file = ord_map;
> > > +	  if (last_include_ord_map &&
> > > !last_ord_map_after_include)
> > > +	    last_ord_map_after_include = ord_map;
> > > +	}
> > > +    }
> > > +
> > > +  /* Determine where to insert the #include.  */
> > > +  const line_map_ordinary *ord_map_for_insertion;
> > > +
> > > +  /* We want the next ordmap in the file after the last one
> > > that's
> > > a
> > > +     #include, but failing that, the start of the file.  */
> > > +  if (last_ord_map_after_include)
> > > +    ord_map_for_insertion = last_ord_map_after_include;
> > > +  else
> > > +    ord_map_for_insertion = first_ord_map_in_file;
> > > +
> > > +  if (!ord_map_for_insertion)
> > > +    return UNKNOWN_LOCATION;
> > > +
> > > +  /* The "start_location" is column 0, meaning "the whole line".
> > > +     rich_location and edit_context can't cope with this, so use
> > > +     column 1 instead.  */
> > > +  location_t col_0 = ord_map_for_insertion->start_location;
> > > +  return linemap_position_for_loc_and_offset (line_table, col_0,
> > > 1);
> > > +}
> > > +
> > > +/* A map from filenames to sets of headers added to them, for
> > > +   ensuring idempotency within maybe_add_include_fixit.  */
> > > +
> > > +/* The values within the map.  We need string comparison as
> > > there's
> > > +   no guarantee that two different diagnostics that are
> > > recommending
> > > +   adding e.g. "<stdio.h>" are using the same buffer.  */
> > > +
> > > +typedef hash_set <const char *, nofree_string_hash>
> > > per_file_includes_t;
> > > +
> > > +/* The map itself.  We don't need string comparison for the
> > > filename
> > > keys,
> > > +   as they come from libcpp.  */
> > > +
> > > +typedef hash_map <const char *, per_file_includes_t *>
> > > added_includes_t;
> > > +static added_includes_t *added_includes;
> > > +
> > > +/* Attempt to add a fix-it hint to RICHLOC, adding "#include
> > > HEADER\n"
> > > +   in a suitable location within the file of RICHLOC's primary
> > > +   location.
> > > +
> > > +   This function is idempotent: a header will be added at most
> > > once
> > > to
> > > +   any given file.  */
> > > +
> > > +void
> > > +maybe_add_include_fixit (rich_location *richloc, const char
> > > *header)
> > > +{
> > > +  const char *file = LOCATION_FILE (richloc->get_loc ());
> > > +  if (!file)
> > > +    return;
> > > +
> > > +  /* Idempotency: don't add the same header more than once to a
> > > given file.  */
> > > +  if (!added_includes)
> > > +    added_includes = new added_includes_t ();
> > > +  per_file_includes_t *&set = added_includes->get_or_insert
> > > (file);
> > > +  if (set)
> > > +    if (set->contains (header))
> > > +      /* ...then we've already added HEADER to that file.  */
> > > +      return;
> > > +  if (!set)
> > > +    set = new per_file_includes_t ();
> > > +  set->add (header);
> > > +
> > > +  /* Attempt to locate a suitable place for the new directive. 
> > >  */
> > > +  location_t include_insert_loc
> > > +    = try_to_locate_new_include_insertion_point (file);
> > > +  if (include_insert_loc == UNKNOWN_LOCATION)
> > > +    return;
> > > +
> > > +  char *text = xasprintf ("#include %s\n", header);
> > > +  richloc->add_fixit_insert_before (include_insert_loc, text);
> > > +  free (text);
> > > +}
> > > +
> > >  #include "gt-c-family-c-common.h"
> > > diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
> > > index 138a0a6..ac8b1bf 100644
> > > --- a/gcc/c-family/c-common.h
> > > +++ b/gcc/c-family/c-common.h
> > > @@ -1554,6 +1554,8 @@ excess_precision_mode_join (enum
> > > flt_eval_method, enum flt_eval_method);
> > >  
> > >  extern int c_flt_eval_method (bool ts18661_p);
> > >  
> > > +extern void maybe_add_include_fixit (rich_location *, const char
> > > *);
> > > +
> > >  #if CHECKING_P
> > >  namespace selftest {
> > >    extern void c_format_c_tests (void);
> > > diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
> > > index 64a1107..41a1728 100644
> > > --- a/gcc/c/c-decl.c
> > > +++ b/gcc/c/c-decl.c
> > > @@ -3412,8 +3412,14 @@ implicitly_declare (location_t loc, tree
> > > functionid)
> > >  		  const char *header
> > >  		    = header_for_builtin_fn (DECL_FUNCTION_CODE
> > > (decl));
> > >  		  if (header != NULL && warned)
> > > -		    inform (loc, "include %qs or provide a
> > > declaration of %qD",
> > > -			    header, decl);
> > > +		    {
> > > +		      rich_location richloc (line_table, loc);
> > > +		      maybe_add_include_fixit (&richloc,
> > > header);
> > > +		      inform_at_rich_loc
> > > +			(&richloc,
> > > +			 "include %qs or provide a declaration
> > > of
> > > %qD",
> > > +			 header, decl);
> > > +		    }
> > >  		  newtype = TREE_TYPE (decl);
> > >  		}
> > >  	    }
> > > diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
> > > index 0c5df93..e6463b8 100644
> > > --- a/gcc/cp/name-lookup.c
> > > +++ b/gcc/cp/name-lookup.c
> > > @@ -4540,7 +4540,7 @@ suggest_alternatives_for (location_t
> > > location,
> > > tree name,
> > >  /* Subroutine of maybe_suggest_missing_header for handling
> > > unrecognized names
> > >     for some of the most common names within "std::".
> > >     Given non-NULL NAME, a name for lookup within "std::", return
> > > the
> > > header
> > > -   name defining it within the C++ Standard Library (without '<'
> > > and
> > > '>'),
> > > +   name defining it within the C++ Standard Library (with '<'
> > > and
> > > '>'),
> > >     or NULL.  */
> > >  
> > >  static const char *
> > > @@ -4553,61 +4553,61 @@ get_std_name_hint (const char *name)
> > >    };
> > >    static const std_name_hint hints[] = {
> > >      /* <array>.  */
> > > -    {"array", "array"}, // C++11
> > > +    {"array", "<array>"}, // C++11
> > >      /* <deque>.  */
> > > -    {"deque", "deque"},
> > > +    {"deque", "<deque>"},
> > >      /* <forward_list>.  */
> > > -    {"forward_list", "forward_list"},  // C++11
> > > +    {"forward_list", "<forward_list>"},  // C++11
> > >      /* <fstream>.  */
> > > -    {"basic_filebuf", "fstream"},
> > > -    {"basic_ifstream", "fstream"},
> > > -    {"basic_ofstream", "fstream"},
> > > -    {"basic_fstream", "fstream"},
> > > +    {"basic_filebuf", "<fstream>"},
> > > +    {"basic_ifstream", "<fstream>"},
> > > +    {"basic_ofstream", "<fstream>"},
> > > +    {"basic_fstream", "<fstream>"},
> > >      /* <iostream>.  */
> > > -    {"cin", "iostream"},
> > > -    {"cout", "iostream"},
> > > -    {"cerr", "iostream"},
> > > -    {"clog", "iostream"},
> > > -    {"wcin", "iostream"},
> > > -    {"wcout", "iostream"},
> > > -    {"wclog", "iostream"},
> > > +    {"cin", "<iostream>"},
> > > +    {"cout", "<iostream>"},
> > > +    {"cerr", "<iostream>"},
> > > +    {"clog", "<iostream>"},
> > > +    {"wcin", "<iostream>"},
> > > +    {"wcout", "<iostream>"},
> > > +    {"wclog", "<iostream>"},
> > >      /* <list>.  */
> > > -    {"list", "list"},
> > > +    {"list", "<list>"},
> > >      /* <map>.  */
> > > -    {"map", "map"},
> > > -    {"multimap", "map"},
> > > +    {"map", "<map>"},
> > > +    {"multimap", "<map>"},
> > >      /* <queue>.  */
> > > -    {"queue", "queue"},
> > > -    {"priority_queue", "queue"},
> > > +    {"queue", "<queue>"},
> > > +    {"priority_queue", "<queue>"},
> > >      /* <ostream>.  */
> > > -    {"ostream", "ostream"},
> > > -    {"wostream", "ostream"},
> > > -    {"ends", "ostream"},
> > > -    {"flush", "ostream"},
> > > -    {"endl", "ostream"},
> > > +    {"ostream", "<ostream>"},
> > > +    {"wostream", "<ostream>"},
> > > +    {"ends", "<ostream>"},
> > > +    {"flush", "<ostream>"},
> > > +    {"endl", "<ostream>"},
> > >      /* <set>.  */
> > > -    {"set", "set"},
> > > -    {"multiset", "set"},
> > > +    {"set", "<set>"},
> > > +    {"multiset", "<set>"},
> > >      /* <sstream>.  */
> > > -    {"basic_stringbuf", "sstream"},
> > > -    {"basic_istringstream", "sstream"},
> > > -    {"basic_ostringstream", "sstream"},
> > > -    {"basic_stringstream", "sstream"},
> > > +    {"basic_stringbuf", "<sstream>"},
> > > +    {"basic_istringstream", "<sstream>"},
> > > +    {"basic_ostringstream", "<sstream>"},
> > > +    {"basic_stringstream", "<sstream>"},
> > >      /* <stack>.  */
> > > -    {"stack", "stack"},
> > > +    {"stack", "<stack>"},
> > >      /* <string>.  */
> > > -    {"string", "string"},
> > > -    {"wstring", "string"},
> > > -    {"u16string", "string"},
> > > -    {"u32string", "string"},
> > > +    {"string", "<string>"},
> > > +    {"wstring", "<string>"},
> > > +    {"u16string", "<string>"},
> > > +    {"u32string", "<string>"},
> > >      /* <unordered_map>.  */
> > > -    {"unordered_map", "unordered_map"}, // C++11
> > > -    {"unordered_multimap", "unordered_map"}, // C++11
> > > +    {"unordered_map", "<unordered_map>"}, // C++11
> > > +    {"unordered_multimap", "<unordered_map>"}, // C++11
> > >      /* <unordered_set>.  */
> > > -    {"unordered_set", "unordered_set"}, // C++11
> > > -    {"unordered_multiset", "unordered_set"}, // C++11
> > > +    {"unordered_set", "<unordered_set>"}, // C++11
> > > +    {"unordered_multiset", "<unordered_set>"}, // C++11
> > >      /* <vector>.  */
> > > -    {"vector", "vector"},
> > > +    {"vector", "<vector>"},
> > >    };
> > >    const size_t num_hints = sizeof (hints) / sizeof (hints[0]);
> > >    for (size_t i = 0; i < num_hints; i++)
> > > @@ -4638,10 +4638,14 @@ maybe_suggest_missing_header (location_t
> > > location, tree name, tree scope)
> > >    const char *name_str = IDENTIFIER_POINTER (name);
> > >    const char *header_hint = get_std_name_hint (name_str);
> > >    if (header_hint)
> > > -    inform (location,
> > > -	    "%<std::%s%> is defined in header %<<%s>%>;"
> > > -	    " did you forget to %<#include <%s>%>?",
> > > -	    name_str, header_hint, header_hint);
> > > +    {
> > > +      gcc_rich_location richloc (location);
> > > +      maybe_add_include_fixit (&richloc, header_hint);
> > > +      inform_at_rich_loc (&richloc,
> > > +			  "%<std::%s%> is defined in header
> > > %qs;"
> > > +			  " did you forget to %<#include %s%>?",
> > > +			  name_str, header_hint, header_hint);
> > > +    }
> > >  }
> > >  
> > >  /* Look for alternatives for NAME, an IDENTIFIER_NODE for which
> > > name
> > > diff --git a/gcc/testsuite/g++.dg/lookup/missing-std-include-2.C
> > > b/gcc/testsuite/g++.dg/lookup/missing-std-include-2.C
> > > new file mode 100644
> > > index 0000000..ae918f8
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/lookup/missing-std-include-2.C
> > > @@ -0,0 +1,55 @@
> > > +/* Example of fix-it hints that add #include directives,
> > > +   adding them after a pre-existing #include.  */
> > > +
> > > +/* { dg-options "-fdiagnostics-generate-patch" } */
> > > +
> > > +/* This is padding (to avoid the generated patch containing
> > > DejaGnu
> > > +   directives).  */
> > > +
> > > +#include <stdio.h>
> > > +
> > > +void test (void)
> > > +{
> > > +  std::string s ("hello world"); // { dg-error ".string. is not
> > > a
> > > member of .std." }
> > > +  // { dg-message ".std::string. is defined in header
> > > .<string>.;
> > > did you forget to .#include <string>.?" "" { target *-*-* } .-1 }
> > > +
> > > +  std::cout << 10; // { dg-error ".cout. is not a member of
> > > .std."
> > > }
> > > +  // { dg-message ".std::cout. is defined in header
> > > .<iostream>.;
> > > did you forget to .#include <iostream>.?" "" { target *-*-* } .-1
> > > }
> > > +}
> > > +
> > > +/* Same again, to test idempotency of the added "#include" fix
> > > -it.
> > >  */
> > > +
> > > +void test_2 (void)
> > > +{
> > > +  std::string s ("hello again"); // { dg-error ".string. is not
> > > a
> > > member of .std." }
> > > +  // { dg-message ".std::string. is defined in header
> > > .<string>.;
> > > did you forget to .#include <string>.?" "" { target *-*-* } .-1 }
> > > +
> > > +  std::cout << 10; // { dg-error ".cout. is not a member of
> > > .std."
> > > }
> > > +  // { dg-message ".std::cout. is defined in header
> > > .<iostream>.;
> > > did you forget to .#include <iostream>.?" "" { target *-*-* } .-1
> > > }
> > > +}
> > > +
> > > +/* Verify the output from -fdiagnostics-generate-patch.
> > > +   We expect the patch to begin with a header, containing this
> > > +   source filename, via an absolute path.
> > > +   Given the path, we can only capture it via regexps.  */
> > > +/* { dg-regexp "\\-\\-\\- .*" } */
> > > +/* { dg-regexp "\\+\\+\\+ .*" } */
> > > +
> > > +/* Verify the hunks within the patch.
> > > +   Use #if 0/#endif rather than comments, to allow the text to
> > > contain
> > > +   a comment.
> > > +   We expect a "#include <string>" and "#include <iostream>" to
> > > each
> > > have been
> > > +   added once, immediately below the last #include.  */
> > > +#if 0
> > > +{ dg-begin-multiline-output "" }
> > > +@@ -7,6 +7,8 @@
> > > +    directives).  */
> > > + 
> > > + #include <stdio.h>
> > > ++#include <string>
> > > ++#include <iostream>
> > > + 
> > > + void test (void)
> > > + {
> > > +{ dg-end-multiline-output "" }
> > > +#endif
> > > diff --git a/gcc/testsuite/gcc.dg/missing-header-fixit-1.c
> > > b/gcc/testsuite/gcc.dg/missing-header-fixit-1.c
> > > new file mode 100644
> > > index 0000000..2b28357
> > > --- /dev/null
> > > +++ b/gcc/testsuite/gcc.dg/missing-header-fixit-1.c
> > > @@ -0,0 +1,36 @@
> > > +/* Example of a fix-it hint that adds a #include directive,
> > > +   adding them to the top of the file, given that there is no
> > > +   pre-existing #include.  */
> > > +
> > > +/* This is padding (to avoid the generated patch containing
> > > DejaGnu
> > > +   directives).  */
> > > +
> > > +/* { dg-options "-fdiagnostics-generate-patch" } */
> > > +
> > > +void test (int i, int j)
> > > +{
> > > +  printf ("%i of %i\n", i, j); /* { dg-warning "implicit
> > > declaration" } */
> > > +  /* { dg-message "include '<stdio.h>' or provide a declaration
> > > of
> > > 'printf'" "" { target *-*-* } .-1 } */
> > > +}
> > > +
> > > +/* Verify the output from -fdiagnostics-generate-patch.
> > > +   We expect the patch to begin with a header, containing this
> > > +   source filename, via an absolute path.
> > > +   Given the path, we can only capture it via regexps.  */
> > > +/* { dg-regexp "\\-\\-\\- .*" } */
> > > +/* { dg-regexp "\\+\\+\\+ .*" } */
> > > +/* Use #if 0/#endif rather than comments, to allow the text to
> > > contain
> > > +   a comment.  */
> > > +#if 0
> > > +{ dg-begin-multiline-output "" }
> > > +@@ -1,3 +1,4 @@
> > > ++#include <stdio.h>
> > > + /* Example of a fix-it hint that adds a #include directive,
> > > +    adding them to the top of the file, given that there is no
> > > +    pre-existing #include.  */
> > > +{ dg-end-multiline-output "" }
> > > +#endif
> > > +
> > > +/* FIXME: should we attempt to skip leading comments when
> > > determining the
> > > +   insertion location?
> > > +   Similarly, should we attempt to be within single-inclusion
> > > guards, etc?  */



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