[1/2] Provide diagnostic hints for missing C inttypes.h string constants.

Message ID 20200524003014.32652-2-mark@klomp.org
State New
Headers show
Series
  • [1/2] Provide diagnostic hints for missing C inttypes.h string constants.
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Commit Message

Mark Wielaard May 24, 2020, 12:30 a.m.
This adds a flag to c_parser so we know when we were trying to
construct a string literal. If there is a parse error and we were
constructing a string literal, and the next token is an unknown
identifier name, and we know there is a standard header that defines
that name as a string literal, then add a missing header hint to
the error messsage.

The list of macro names are also used when providing a hint for
missing identifiers.

gcc/c-family/ChangeLog:

	* known-headers.cc (get_string_macro_hint): New function.
	(get_stdlib_header_for_name): Use get_string_macro_hint.
	(get_c_stdlib_header_for_string_macro_name): New function.
	* known-headers.h (get_c_stdlib_header_for_string_macro_name):
	New function definition.

gcc/c/ChangeLog:

	* c-parser.c (struct c_parser): Add seen_string_literal
	bitfield.
	(c_parser_consume_token): Reset seen_string_literal.
	(c_parser_error_richloc): Add name_hint if seen_string_literal
	and next token is a CPP_NAME and we have a missing header
	suggestion for the name.
	(c_parser_string_literal): Set seen_string_literal.

gcc/testsuite/ChangeLog:

	* gcc.dg/spellcheck-inttypes.c: New test.
	* g++.dg/spellcheck-inttypes.C: Likewise.
---
 gcc/c-family/known-headers.cc              | 53 ++++++++++++++-
 gcc/c-family/known-headers.h               |  2 +
 gcc/c/c-parser.c                           | 29 ++++++++
 gcc/testsuite/g++.dg/spellcheck-inttypes.C | 41 ++++++++++++
 gcc/testsuite/gcc.dg/spellcheck-inttypes.c | 78 ++++++++++++++++++++++
 5 files changed, 202 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/spellcheck-inttypes.C
 create mode 100644 gcc/testsuite/gcc.dg/spellcheck-inttypes.c

-- 
2.20.1

Comments

Mark Wielaard June 1, 2020, 12:01 p.m. | #1
On Sun, May 24, 2020 at 02:30:13AM +0200, Mark Wielaard wrote:
> This adds a flag to c_parser so we know when we were trying to

> construct a string literal. If there is a parse error and we were

> constructing a string literal, and the next token is an unknown

> identifier name, and we know there is a standard header that defines

> that name as a string literal, then add a missing header hint to

> the error messsage.

> 

> The list of macro names are also used when providing a hint for

> missing identifiers.


Ping. Note the followup patch that introduces the same functionality
for the C++ parser was already approved. This patch (as attached) only
needs review/approval from a C-frontend maintainer for some of the
gcc/c/c-parser.c bits.

Thanks,

Mark
From 1aceca275a73b4c7991a6fbde45f4d6da1a9daf5 Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mark@klomp.org>

Date: Fri, 22 May 2020 01:10:50 +0200
Subject: [PATCH] Provide diagnostic hints for missing C inttypes.h string
 constants.

This adds a flag to c_parser so we know when we were trying to
construct a string literal. If there is a parse error and we were
constructing a string literal, and the next token is an unknown
identifier name, and we know there is a standard header that defines
that name as a string literal, then add a missing header hint to
the error messsage.

The list of macro names are also used when providing a hint for
missing identifiers.

gcc/c-family/ChangeLog:

	* known-headers.cc (get_string_macro_hint): New function.
	(get_stdlib_header_for_name): Use get_string_macro_hint.
	(get_c_stdlib_header_for_string_macro_name): New function.
	* known-headers.h (get_c_stdlib_header_for_string_macro_name):
	New function declaration.

gcc/c/ChangeLog:

	* c-parser.c (struct c_parser): Add seen_string_literal
	bitfield.
	(c_parser_consume_token): Reset seen_string_literal.
	(c_parser_error_richloc): Add name_hint if seen_string_literal
	and next token is a CPP_NAME and we have a missing header
	suggestion for the name.
	(c_parser_string_literal): Set seen_string_literal.

gcc/testsuite/ChangeLog:

	* gcc.dg/spellcheck-inttypes.c: New test.
	* g++.dg/spellcheck-inttypes.C: Likewise.
---
 gcc/c-family/known-headers.cc              | 53 ++++++++++++++-
 gcc/c-family/known-headers.h               |  2 +
 gcc/c/c-parser.c                           | 29 ++++++++
 gcc/testsuite/g++.dg/spellcheck-inttypes.C | 41 ++++++++++++
 gcc/testsuite/gcc.dg/spellcheck-inttypes.c | 78 ++++++++++++++++++++++
 5 files changed, 202 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/spellcheck-inttypes.C
 create mode 100644 gcc/testsuite/gcc.dg/spellcheck-inttypes.c

diff --git a/gcc/c-family/known-headers.cc b/gcc/c-family/known-headers.cc
index 1e2bf49c439a..c07cfd1db815 100644
--- a/gcc/c-family/known-headers.cc
+++ b/gcc/c-family/known-headers.cc
@@ -46,6 +46,49 @@ struct stdlib_hint
   const char *header[NUM_STDLIBS];
 };
 
+/* Given non-NULL NAME, return the header name defining it (as literal
+   string) within either the standard library (with '<' and '>'), or
+   NULL.
+
+   Only handle string macros, so that this can be used for
+   get_stdlib_header_for_name and
+   get_c_stdlib_header_for_string_macro_name.  */
+
+static const char *
+get_string_macro_hint (const char *name, enum stdlib lib)
+{
+  /* <inttypes.h> and <cinttypes>.  */
+  static const char *c99_cxx11_macros[] =
+    { "PRId8", "PRId16", "PRId32", "PRId64",
+      "PRIi8", "PRIi16", "PRIi32", "PRIi64",
+      "PRIo8", "PRIo16", "PRIo32", "PRIo64",
+      "PRIu8", "PRIu16", "PRIu32", "PRIu64",
+      "PRIx8", "PRIx16", "PRIx32", "PRIx64",
+      "PRIX8", "PRIX16", "PRIX32", "PRIX64",
+
+      "PRIdPTR", "PRIiPTR", "PRIoPTR", "PRIuPTR", "PRIxPTR", "PRIXPTR",
+
+      "SCNd8", "SCNd16", "SCNd32", "SCNd64",
+      "SCNi8", "SCNi16", "SCNi32", "SCNi64",
+      "SCNo8", "SCNo16", "SCNo32", "SCNo64",
+      "SCNu8", "SCNu16", "SCNu32", "SCNu64",
+      "SCNx8", "SCNx16", "SCNx32", "SCNx64",
+
+      "SCNdPTR", "SCNiPTR", "SCNoPTR", "SCNuPTR", "SCNxPTR" };
+
+  if ((lib == STDLIB_C && flag_isoc99)
+      || (lib == STDLIB_CPLUSPLUS && cxx_dialect >= cxx11 ))
+    {
+      const size_t num_c99_cxx11_macros
+	= sizeof (c99_cxx11_macros) / sizeof (c99_cxx11_macros[0]);
+      for (size_t i = 0; i < num_c99_cxx11_macros; i++)
+	if (strcmp (name, c99_cxx11_macros[i]) == 0)
+	  return lib == STDLIB_C ? "<inttypes.h>" : "<cinttypes>";
+    }
+
+  return NULL;
+}
+
 /* Given non-NULL NAME, return the header name defining it within either
    the standard library (with '<' and '>'), or NULL.
    Only handles a subset of the most common names within the stdlibs.  */
@@ -196,7 +239,7 @@ get_stdlib_header_for_name (const char *name, enum stdlib lib)
       if (strcmp (name, c99_cxx11_hints[i].name) == 0)
 	return c99_cxx11_hints[i].header[lib];
 
-  return NULL;
+  return get_string_macro_hint (name, lib);
 }
 
 /* Given non-NULL NAME, return the header name defining it within the C
@@ -217,6 +260,14 @@ get_cp_stdlib_header_for_name (const char *name)
   return get_stdlib_header_for_name (name, STDLIB_CPLUSPLUS);
 }
 
+/* Given non-NULL NAME, return the header name defining a string macro
+   within the C standard library (with '<' and '>'), or NULL.  */
+const char *
+get_c_stdlib_header_for_string_macro_name (const char *name)
+{
+  return get_string_macro_hint (name, STDLIB_C);
+}
+
 /* Implementation of class suggest_missing_header.  */
 
 /* suggest_missing_header's ctor.  */
diff --git a/gcc/c-family/known-headers.h b/gcc/c-family/known-headers.h
index 4ec4e23fc88d..a69bbbf28e76 100644
--- a/gcc/c-family/known-headers.h
+++ b/gcc/c-family/known-headers.h
@@ -23,6 +23,8 @@ along with GCC; see the file COPYING3.  If not see
 extern const char *get_c_stdlib_header_for_name (const char *name);
 extern const char *get_cp_stdlib_header_for_name (const char *name);
 
+extern const char *get_c_stdlib_header_for_string_macro_name (const char *n);
+
 /* Subclass of deferred_diagnostic for suggesting to the user
    that they have missed a #include.  */
 
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 23d6fa22b685..df0b59f9f95c 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -69,6 +69,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "c-family/name-hint.h"
 #include "tree-iterator.h"
 #include "memmodel.h"
+#include "c-family/known-headers.h"
 
 /* We need to walk over decls with incomplete struct/union/enum types
    after parsing the whole translation unit.
@@ -223,6 +224,13 @@ struct GTY(()) c_parser {
      keywords are valid.  */
   BOOL_BITFIELD objc_property_attr_context : 1;
 
+  /* Whether we have just seen/constructed a string-literal.  Set when
+     returning a string-literal from c_parser_string_literal.  Reset
+     in consume_token.  Useful when we get a parse error and see an
+     unknown token, which could have been a string-literal constant
+     macro.  */
+  BOOL_BITFIELD seen_string_literal : 1;
+
   /* Location of the last consumed token.  */
   location_t last_token_location;
 };
@@ -853,6 +861,7 @@ c_parser_consume_token (c_parser *parser)
         }
     }
   parser->tokens_avail--;
+  parser->seen_string_literal = false;
 }
 
 /* Expect the current token to be a #pragma.  Consume it and remember
@@ -966,6 +975,25 @@ c_parser_error_richloc (c_parser *parser, const char *gmsgid,
 	}
     }
 
+  /* If we were parsing a string-literal and there is an unknown name
+     token right after, then check to see if that could also have been
+     a literal string by checking the name against a list of known
+     standard string literal constants defined in header files. If
+     there is one, then add that as an hint to the error message. */
+  auto_diagnostic_group d;
+  name_hint h;
+  if (parser->seen_string_literal && token->type == CPP_NAME)
+    {
+      tree name = token->value;
+      const char *token_name = IDENTIFIER_POINTER (name);
+      const char *header_hint
+	= get_c_stdlib_header_for_string_macro_name (token_name);
+      if (header_hint != NULL)
+	h = name_hint (NULL, new suggest_missing_header (token->location,
+							 token_name,
+							 header_hint));
+    }
+
   c_parse_error (gmsgid,
 		 /* Because c_parse_error does not understand
 		    CPP_KEYWORD, keywords are treated like
@@ -7539,6 +7567,7 @@ c_parser_string_literal (c_parser *parser, bool translate, bool wide_ok)
   ret.original_code = STRING_CST;
   ret.original_type = NULL_TREE;
   set_c_expr_source_range (&ret, get_range_from_loc (line_table, loc));
+  parser->seen_string_literal = true;
   return ret;
 }
 
diff --git a/gcc/testsuite/g++.dg/spellcheck-inttypes.C b/gcc/testsuite/g++.dg/spellcheck-inttypes.C
new file mode 100644
index 000000000000..c5861127ca6d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/spellcheck-inttypes.C
@@ -0,0 +1,41 @@
+/* { dg-options "-std=c++11" } */
+#include <cstdio>
+#include <cstdint>
+/* Missing <cinttypes>.  */
+
+int8_t i8;
+int16_t i16;
+int32_t i32;
+int64_t i64;
+
+intptr_t ip;
+uintptr_t up;
+
+/* As an identifier.  */
+const char *hex8_fmt = PRIx8; /* { dg-error "'PRIx8' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx8' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex16_fmt = PRIx16; /* { dg-error "'PRIx16' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx16' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex32_fmt = PRIx32; /* { dg-error "'PRIx32' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx32' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex64_fmt = PRIx64; /* { dg-error "'PRIx64' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx64' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hexptr_fmt = PRIxPTR; /* { dg-error "'PRIxPTR' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIxPTR' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+
+void test_printf (void)
+{
+  printf ("some format strings %s, %s, %s, %s, %s, %s\n",
+	  PRId8, /* { dg-error "'PRId8' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRId8' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIi16, /* { dg-error "'PRIi16' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIi16' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIo32, /* { dg-error "'PRIo32' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIo32' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIu64, /* { dg-error "'PRIu64' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIu64' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIx32, /* { dg-error "'PRIx32' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx32' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIoPTR);  /* { dg-error "'PRIoPTR' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIoPTR' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+}
diff --git a/gcc/testsuite/gcc.dg/spellcheck-inttypes.c b/gcc/testsuite/gcc.dg/spellcheck-inttypes.c
new file mode 100644
index 000000000000..56dc2f3dcfd9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/spellcheck-inttypes.c
@@ -0,0 +1,78 @@
+/* { dg-options "-std=c99" } */
+#include <stdio.h>
+#include <stdint.h>
+/* Missing <inttypes.h>.  */
+
+int8_t i8;
+int16_t i16;
+int32_t i32;
+int64_t i64;
+
+intptr_t ip;
+uintptr_t up;
+
+/* As an identifier.  */
+const char *hex8_fmt = PRIx8; /* { dg-error "'PRIx8' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx8' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex16_fmt = PRIx16; /* { dg-error "'PRIx16' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx16' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex32_fmt = PRIx32; /* { dg-error "'PRIx32' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx32' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex64_fmt = PRIx64; /* { dg-error "'PRIx64' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hexptr_fmt = PRIxPTR; /* { dg-error "'PRIxPTR' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIxPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+
+/* As a part of a string-literal.  */
+const char *dec8msg_fmt = "Provide %" PRId8 "\n"; /* { dg-error "expected" "expected string-literal" { target *-*-* } } */
+/* { dg-message "'PRId8' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *dec16msg_fmt = "Provide %" PRId16 "\n"; /* { dg-error "expected" "expected string-literal" { target *-*-* } } */
+/* { dg-message "'PRId16' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *dec32msg_fmt = "Provide %" PRId32 "\n"; /* { dg-error "expected" "expected string-literal" { target *-*-* } } */
+/* { dg-message "'PRId32' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *dec64msg_fmt = "Provide %" PRId64 "\n"; /* { dg-error "expected" "expected string-literal" { target *-*-* } } */
+/* { dg-message "'PRId64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *decptrmsg_fmt = "Provide %" PRIdPTR "\n"; /* { dg-error "expected" "expected string-literal" { target *-*-* } } */
+/* { dg-message "'PRIdPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+
+void test_printf (void)
+{
+  printf ("some format strings %s, %s, %s, %s, %s, %s\n",
+	  PRId8, /* { dg-error "'PRId8' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRId8' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIi16, /* { dg-error "'PRIi16' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIi16' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIo32, /* { dg-error "'PRIo32' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIo32' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIu64, /* { dg-error "'PRIu64' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIu64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIoPTR);  /* { dg-error "'PRIoPTR' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIoPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+
+  printf ("%" PRIo8 "\n", i8); /* { dg-error "expected" } */
+/* { dg-message "'PRIo8' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  printf ("%" PRIo16 "\n", i16); /* { dg-error "expected" } */
+/* { dg-message "'PRIo16' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  printf ("%" PRIo32 "\n", i32); /* { dg-error "expected" } */
+/* { dg-message "'PRIo32' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  printf ("%" PRIo64 "\n", i64); /* { dg-error "expected" } */
+/* { dg-message "'PRIo64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  printf ("%" PRIoPTR "\n", ip); /* { dg-error "expected" } */
+/* { dg-message "'PRIoPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+}
+
+void test_scanf (void)
+{
+  scanf ("%" SCNu8 "\n", &i8); /* { dg-error "expected" } */
+/* { dg-message "'SCNu8' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  scanf ("%" SCNu16 "\n", &i16); /* { dg-error "expected" } */
+/* { dg-message "'SCNu16' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  scanf ("%" SCNu32 "\n", &i32); /* { dg-error "expected" } */
+/* { dg-message "'SCNu32' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  scanf ("%" SCNu64 "\n", &i64); /* { dg-error "expected" } */
+/* { dg-message "'SCNu64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  scanf ("%" SCNuPTR "\n", &ip); /* { dg-error "expected" } */
+/* { dg-message "'SCNuPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  scanf ("%" SCNxPTR "\n", &up); /* { dg-error "expected" } */
+/* { dg-message "'SCNxPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+}
-- 
2.20.1
Joseph Myers June 3, 2020, 11:17 p.m. | #2
On Mon, 1 Jun 2020, Mark Wielaard wrote:

> On Sun, May 24, 2020 at 02:30:13AM +0200, Mark Wielaard wrote:

> > This adds a flag to c_parser so we know when we were trying to

> > construct a string literal. If there is a parse error and we were

> > constructing a string literal, and the next token is an unknown

> > identifier name, and we know there is a standard header that defines

> > that name as a string literal, then add a missing header hint to

> > the error messsage.

> > 

> > The list of macro names are also used when providing a hint for

> > missing identifiers.

> 

> Ping. Note the followup patch that introduces the same functionality

> for the C++ parser was already approved. This patch (as attached) only

> needs review/approval from a C-frontend maintainer for some of the

> gcc/c/c-parser.c bits.


This patch is OK.

-- 
Joseph S. Myers
joseph@codesourcery.com

Patch

diff --git a/gcc/c-family/known-headers.cc b/gcc/c-family/known-headers.cc
index 1e2bf49c439a..c07cfd1db815 100644
--- a/gcc/c-family/known-headers.cc
+++ b/gcc/c-family/known-headers.cc
@@ -46,6 +46,49 @@  struct stdlib_hint
   const char *header[NUM_STDLIBS];
 };
 
+/* Given non-NULL NAME, return the header name defining it (as literal
+   string) within either the standard library (with '<' and '>'), or
+   NULL.
+
+   Only handle string macros, so that this can be used for
+   get_stdlib_header_for_name and
+   get_c_stdlib_header_for_string_macro_name.  */
+
+static const char *
+get_string_macro_hint (const char *name, enum stdlib lib)
+{
+  /* <inttypes.h> and <cinttypes>.  */
+  static const char *c99_cxx11_macros[] =
+    { "PRId8", "PRId16", "PRId32", "PRId64",
+      "PRIi8", "PRIi16", "PRIi32", "PRIi64",
+      "PRIo8", "PRIo16", "PRIo32", "PRIo64",
+      "PRIu8", "PRIu16", "PRIu32", "PRIu64",
+      "PRIx8", "PRIx16", "PRIx32", "PRIx64",
+      "PRIX8", "PRIX16", "PRIX32", "PRIX64",
+
+      "PRIdPTR", "PRIiPTR", "PRIoPTR", "PRIuPTR", "PRIxPTR", "PRIXPTR",
+
+      "SCNd8", "SCNd16", "SCNd32", "SCNd64",
+      "SCNi8", "SCNi16", "SCNi32", "SCNi64",
+      "SCNo8", "SCNo16", "SCNo32", "SCNo64",
+      "SCNu8", "SCNu16", "SCNu32", "SCNu64",
+      "SCNx8", "SCNx16", "SCNx32", "SCNx64",
+
+      "SCNdPTR", "SCNiPTR", "SCNoPTR", "SCNuPTR", "SCNxPTR" };
+
+  if ((lib == STDLIB_C && flag_isoc99)
+      || (lib == STDLIB_CPLUSPLUS && cxx_dialect >= cxx11 ))
+    {
+      const size_t num_c99_cxx11_macros
+	= sizeof (c99_cxx11_macros) / sizeof (c99_cxx11_macros[0]);
+      for (size_t i = 0; i < num_c99_cxx11_macros; i++)
+	if (strcmp (name, c99_cxx11_macros[i]) == 0)
+	  return lib == STDLIB_C ? "<inttypes.h>" : "<cinttypes>";
+    }
+
+  return NULL;
+}
+
 /* Given non-NULL NAME, return the header name defining it within either
    the standard library (with '<' and '>'), or NULL.
    Only handles a subset of the most common names within the stdlibs.  */
@@ -196,7 +239,7 @@  get_stdlib_header_for_name (const char *name, enum stdlib lib)
       if (strcmp (name, c99_cxx11_hints[i].name) == 0)
 	return c99_cxx11_hints[i].header[lib];
 
-  return NULL;
+  return get_string_macro_hint (name, lib);
 }
 
 /* Given non-NULL NAME, return the header name defining it within the C
@@ -217,6 +260,14 @@  get_cp_stdlib_header_for_name (const char *name)
   return get_stdlib_header_for_name (name, STDLIB_CPLUSPLUS);
 }
 
+/* Given non-NULL NAME, return the header name defining a string macro
+   within the C standard library (with '<' and '>'), or NULL.  */
+const char *
+get_c_stdlib_header_for_string_macro_name (const char *name)
+{
+  return get_string_macro_hint (name, STDLIB_C);
+}
+
 /* Implementation of class suggest_missing_header.  */
 
 /* suggest_missing_header's ctor.  */
diff --git a/gcc/c-family/known-headers.h b/gcc/c-family/known-headers.h
index 4ec4e23fc88d..a69bbbf28e76 100644
--- a/gcc/c-family/known-headers.h
+++ b/gcc/c-family/known-headers.h
@@ -23,6 +23,8 @@  along with GCC; see the file COPYING3.  If not see
 extern const char *get_c_stdlib_header_for_name (const char *name);
 extern const char *get_cp_stdlib_header_for_name (const char *name);
 
+extern const char *get_c_stdlib_header_for_string_macro_name (const char *n);
+
 /* Subclass of deferred_diagnostic for suggesting to the user
    that they have missed a #include.  */
 
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 5d11e7e73c16..db8f86a8e2f0 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -69,6 +69,7 @@  along with GCC; see the file COPYING3.  If not see
 #include "c-family/name-hint.h"
 #include "tree-iterator.h"
 #include "memmodel.h"
+#include "c-family/known-headers.h"
 
 /* We need to walk over decls with incomplete struct/union/enum types
    after parsing the whole translation unit.
@@ -223,6 +224,13 @@  struct GTY(()) c_parser {
      keywords are valid.  */
   BOOL_BITFIELD objc_property_attr_context : 1;
 
+  /* Whether we have just seen/constructed a string-literal.  Set when
+     returning a string-literal from c_parser_string_literal.  Reset
+     in consume_token.  Useful when we get a parse error and see an
+     unknown token, which could have been a string-literal constant
+     macro.  */
+  BOOL_BITFIELD seen_string_literal : 1;
+
   /* Location of the last consumed token.  */
   location_t last_token_location;
 };
@@ -853,6 +861,7 @@  c_parser_consume_token (c_parser *parser)
         }
     }
   parser->tokens_avail--;
+  parser->seen_string_literal = false;
 }
 
 /* Expect the current token to be a #pragma.  Consume it and remember
@@ -966,6 +975,25 @@  c_parser_error_richloc (c_parser *parser, const char *gmsgid,
 	}
     }
 
+  /* If we were parsing a string-literal and there is an unknown name
+     token right after, then check to see if that could also have been
+     a literal string by checking the name against a list of known
+     standard string literal constants defined in header files. If
+     there is one, then add that as an hint to the error message. */
+  auto_diagnostic_group d;
+  name_hint h;
+  if (parser->seen_string_literal && token->type == CPP_NAME)
+    {
+      tree name = token->value;
+      const char *token_name = IDENTIFIER_POINTER (name);
+      const char *header_hint
+	= get_c_stdlib_header_for_string_macro_name (token_name);
+      if (header_hint != NULL)
+	h = name_hint (NULL, new suggest_missing_header (token->location,
+							 token_name,
+							 header_hint));
+    }
+
   c_parse_error (gmsgid,
 		 /* Because c_parse_error does not understand
 		    CPP_KEYWORD, keywords are treated like
@@ -7539,6 +7567,7 @@  c_parser_string_literal (c_parser *parser, bool translate, bool wide_ok)
   ret.original_code = STRING_CST;
   ret.original_type = NULL_TREE;
   set_c_expr_source_range (&ret, get_range_from_loc (line_table, loc));
+  parser->seen_string_literal = true;
   return ret;
 }
 
diff --git a/gcc/testsuite/g++.dg/spellcheck-inttypes.C b/gcc/testsuite/g++.dg/spellcheck-inttypes.C
new file mode 100644
index 000000000000..c5861127ca6d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/spellcheck-inttypes.C
@@ -0,0 +1,41 @@ 
+/* { dg-options "-std=c++11" } */
+#include <cstdio>
+#include <cstdint>
+/* Missing <cinttypes>.  */
+
+int8_t i8;
+int16_t i16;
+int32_t i32;
+int64_t i64;
+
+intptr_t ip;
+uintptr_t up;
+
+/* As an identifier.  */
+const char *hex8_fmt = PRIx8; /* { dg-error "'PRIx8' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx8' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex16_fmt = PRIx16; /* { dg-error "'PRIx16' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx16' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex32_fmt = PRIx32; /* { dg-error "'PRIx32' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx32' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex64_fmt = PRIx64; /* { dg-error "'PRIx64' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx64' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hexptr_fmt = PRIxPTR; /* { dg-error "'PRIxPTR' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIxPTR' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+
+void test_printf (void)
+{
+  printf ("some format strings %s, %s, %s, %s, %s, %s\n",
+	  PRId8, /* { dg-error "'PRId8' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRId8' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIi16, /* { dg-error "'PRIi16' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIi16' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIo32, /* { dg-error "'PRIo32' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIo32' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIu64, /* { dg-error "'PRIu64' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIu64' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIx32, /* { dg-error "'PRIx32' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx32' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIoPTR);  /* { dg-error "'PRIoPTR' was not declared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIoPTR' is defined in header '<cinttypes>'; did you forget to '#include <cinttypes>'?" "replacement note" { target *-*-* } .-1 } */
+}
diff --git a/gcc/testsuite/gcc.dg/spellcheck-inttypes.c b/gcc/testsuite/gcc.dg/spellcheck-inttypes.c
new file mode 100644
index 000000000000..56dc2f3dcfd9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/spellcheck-inttypes.c
@@ -0,0 +1,78 @@ 
+/* { dg-options "-std=c99" } */
+#include <stdio.h>
+#include <stdint.h>
+/* Missing <inttypes.h>.  */
+
+int8_t i8;
+int16_t i16;
+int32_t i32;
+int64_t i64;
+
+intptr_t ip;
+uintptr_t up;
+
+/* As an identifier.  */
+const char *hex8_fmt = PRIx8; /* { dg-error "'PRIx8' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx8' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex16_fmt = PRIx16; /* { dg-error "'PRIx16' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx16' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex32_fmt = PRIx32; /* { dg-error "'PRIx32' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx32' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hex64_fmt = PRIx64; /* { dg-error "'PRIx64' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIx64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *hexptr_fmt = PRIxPTR; /* { dg-error "'PRIxPTR' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIxPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+
+/* As a part of a string-literal.  */
+const char *dec8msg_fmt = "Provide %" PRId8 "\n"; /* { dg-error "expected" "expected string-literal" { target *-*-* } } */
+/* { dg-message "'PRId8' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *dec16msg_fmt = "Provide %" PRId16 "\n"; /* { dg-error "expected" "expected string-literal" { target *-*-* } } */
+/* { dg-message "'PRId16' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *dec32msg_fmt = "Provide %" PRId32 "\n"; /* { dg-error "expected" "expected string-literal" { target *-*-* } } */
+/* { dg-message "'PRId32' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *dec64msg_fmt = "Provide %" PRId64 "\n"; /* { dg-error "expected" "expected string-literal" { target *-*-* } } */
+/* { dg-message "'PRId64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+const char *decptrmsg_fmt = "Provide %" PRIdPTR "\n"; /* { dg-error "expected" "expected string-literal" { target *-*-* } } */
+/* { dg-message "'PRIdPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+
+void test_printf (void)
+{
+  printf ("some format strings %s, %s, %s, %s, %s, %s\n",
+	  PRId8, /* { dg-error "'PRId8' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRId8' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIi16, /* { dg-error "'PRIi16' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIi16' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIo32, /* { dg-error "'PRIo32' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIo32' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIu64, /* { dg-error "'PRIu64' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIu64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+	  PRIoPTR);  /* { dg-error "'PRIoPTR' undeclared" "undeclared identifier" { target *-*-* } } */
+/* { dg-message "'PRIoPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+
+  printf ("%" PRIo8 "\n", i8); /* { dg-error "expected" } */
+/* { dg-message "'PRIo8' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  printf ("%" PRIo16 "\n", i16); /* { dg-error "expected" } */
+/* { dg-message "'PRIo16' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  printf ("%" PRIo32 "\n", i32); /* { dg-error "expected" } */
+/* { dg-message "'PRIo32' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  printf ("%" PRIo64 "\n", i64); /* { dg-error "expected" } */
+/* { dg-message "'PRIo64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  printf ("%" PRIoPTR "\n", ip); /* { dg-error "expected" } */
+/* { dg-message "'PRIoPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+}
+
+void test_scanf (void)
+{
+  scanf ("%" SCNu8 "\n", &i8); /* { dg-error "expected" } */
+/* { dg-message "'SCNu8' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  scanf ("%" SCNu16 "\n", &i16); /* { dg-error "expected" } */
+/* { dg-message "'SCNu16' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  scanf ("%" SCNu32 "\n", &i32); /* { dg-error "expected" } */
+/* { dg-message "'SCNu32' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  scanf ("%" SCNu64 "\n", &i64); /* { dg-error "expected" } */
+/* { dg-message "'SCNu64' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  scanf ("%" SCNuPTR "\n", &ip); /* { dg-error "expected" } */
+/* { dg-message "'SCNuPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+  scanf ("%" SCNxPTR "\n", &up); /* { dg-error "expected" } */
+/* { dg-message "'SCNxPTR' is defined in header '<inttypes.h>'; did you forget to '#include <inttypes.h>'?" "replacement note" { target *-*-* } .-1 } */
+}