libcpp: show macro definition when used with wrong argument count

Consider:

demo.c: In function 'test':
demo.c:5:40: error: macro "LOG_2" requires 3 arguments, but only 2 given
5 |   LOG_2 ("loading file: %s\n", filename);
  |                                        ^

This patch adds a note showing the definition of the macro in
question, giving:

demo.c: In function 'test':
demo.c:5:40: error: macro "LOG_2" requires 3 arguments, but only 2 given
5 |   LOG_2 ("loading file: %s\n", filename);
  |                                        ^
In file included from demo.c:1:
logging.h:1: note: macro "LOG_2" defined here
1 | #define LOG_2(FMT, ARG0, ARG1) do { fprintf (stderr, (FMT), (ARG0), (ARG1)); }
  | 

gcc/testsuite/ChangeLog:
	* g++.dg/diagnostic/macro-arg-count.C: Move to...
	* c-c++-common/cpp/macro-arg-count-1.c: ...here, generalizing
	output for C vs C++.  Expect notes showing the definitions of the
	macros.
	* c-c++-common/cpp/macro-arg-count-2.c: New test, adapted from the
	above.

libcpp/ChangeLog:
	* macro.c (_cpp_arguments_ok): If the argument count is wrong, add
	a note showing the definition of the macro.

From-SVN: r265040

6 files changed, 120 insertions, 51 deletions

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a0a5dbb55f2..3588376437b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2018-10-11  David Malcolm  <dmalcolm@redhat.com>
+
+	* g++.dg/diagnostic/macro-arg-count.C: Move to...
+	* c-c++-common/cpp/macro-arg-count-1.c: ...here, generalizing
+	output for C vs C++.  Expect notes showing the definitions of the
+	macros.
+	* c-c++-common/cpp/macro-arg-count-2.c: New test, adapted from the
+	above.
+
 2018-10-11  Martin Jambor  <mjambor@suse.cz>
 
 	* gcc.dg/warn-abs-1.c: Guard tests assuming size of long double is
diff --git a/gcc/testsuite/c-c++-common/cpp/macro-arg-count-1.c b/gcc/testsuite/c-c++-common/cpp/macro-arg-count-1.c
new file mode 100644
index 00000000000..7773c47e765
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/macro-arg-count-1.c
@@ -0,0 +1,66 @@
+/* { dg-options "-fdiagnostics-show-caret" } */
+
+#define MACRO_1(X,Y) /* { dg-line "def_of_MACRO_1" } */
+void test_1 ()
+{
+  MACRO_1(42); /* { dg-line "use_of_MACRO_1" } */
+  /* { dg-error "macro \"MACRO_1\" requires 2 arguments, but only 1 given" "" { target *-*-* } use_of_MACRO_1 } */
+  /* { dg-begin-multiline-output "" }
+   MACRO_1(42);
+             ^
+     { dg-end-multiline-output "" } */
+  /* { dg-message "-: macro .MACRO_1. defined here" "" { target *-*-* } def_of_MACRO_1 }
+  /* { dg-begin-multiline-output "" }
+ #define MACRO_1(X,Y)
+ 
+     { dg-end-multiline-output "" } */
+  /* { dg-error "'MACRO_1' undeclared" "" { target c } use_of_MACRO_1 }
+  /* { dg-error "'MACRO_1' was not declared in this scope" "" { target c++ } use_of_MACRO_1 }
+
+  /* { dg-begin-multiline-output "" }
+   MACRO_1(42);
+   ^~~~~~~
+     { dg-end-multiline-output "" } */
+  /* { dg-bogus "had not yet been defined" "" { target *-*-* } use_of_MACRO_1 } */
+}
+
+#define MACRO_2(X,Y) /* { dg-line "def_of_MACRO_2" } */
+void test_2 ()
+{
+  MACRO_2(1, 2, 3); /* { dg-line "use_of_MACRO_2" } */
+  /* { dg-error "macro \"MACRO_2\" passed 3 arguments, but takes just 2" "" { target *-*-* } use_of_MACRO_2 } */
+  /* { dg-begin-multiline-output "" }
+   MACRO_2(1, 2, 3);
+                  ^
+     { dg-end-multiline-output "" } */
+  /* { dg-message "-: macro .MACRO_2. defined here" "" { target *-*-* } def_of_MACRO_2 }
+  /* { dg-begin-multiline-output "" }
+ #define MACRO_2(X,Y)
+ 
+     { dg-end-multiline-output "" } */
+  /* { dg-error "'MACRO_2' undeclared" "" { target c } use_of_MACRO_2 } */
+  /* { dg-error "'MACRO_2' was not declared in this scope" "" { target c++ } use_of_MACRO_2 } */
+  /* { dg-begin-multiline-output "" }
+   MACRO_2(1, 2, 3);
+   ^~~~~~~
+     { dg-end-multiline-output "" } */
+  /* { dg-bogus "had not yet been defined" "" { target *-*-* } use_of_MACRO_2 } */
+}
+
+#define MACRO_3
+void test_3 ()
+{
+  MACRO_3 (42);
+}
+
+#define MACRO_4(X,Y)
+void test_4 ()
+{
+  MACRO_4; /* { dg-line "use_of_MACRO_4" } */
+  /* { dg-error "'MACRO_4' undeclared" "" { target c } use_of_MACRO_4 } */
+  /* { dg-error "'MACRO_4' was not declared in this scope" "" { target c++ } use_of_MACRO_4 } */
+  /* { dg-begin-multiline-output "" }
+   MACRO_4;
+   ^~~~~~~
+     { dg-end-multiline-output "" } */
+}
diff --git a/gcc/testsuite/c-c++-common/cpp/macro-arg-count-2.c b/gcc/testsuite/c-c++-common/cpp/macro-arg-count-2.c
new file mode 100644
index 00000000000..ef64488348d
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/macro-arg-count-2.c
@@ -0,0 +1,36 @@
+/* { dg-options "-traditional-cpp" } */
+
+#define MACRO_1(X,Y) /* { dg-line "def_of_MACRO_1" } */
+void test_1 ()
+{
+  MACRO_1(42); /* { dg-line "use_of_MACRO_1" } */
+  /* { dg-error "-:macro \"MACRO_1\" requires 2 arguments, but only 1 given" "" { target c } use_of_MACRO_1 } */
+  /* { dg-error "macro \"MACRO_1\" requires 2 arguments, but only 1 given" "" { target c++ } use_of_MACRO_1 } */
+  /* { dg-message "-: macro .MACRO_1. defined here" "" { target *-*-* } def_of_MACRO_1 } */
+  /* { dg-error "'MACRO_1' was not declared in this scope" "" { target c++ } use_of_MACRO_1 } */
+  /* { dg-bogus "had not yet been defined" "" { target *-*-* } use_of_MACRO_1 } */
+}
+
+#define MACRO_2(X,Y) /* { dg-line "def_of_MACRO_2" } */
+void test_2 ()
+{
+  MACRO_2(1, 2, 3); /* { dg-line "use_of_MACRO_2" } */
+  /* { dg-error "-:macro \"MACRO_2\" passed 3 arguments, but takes just 2" "" { target c } use_of_MACRO_2 } */
+  /* { dg-error "macro \"MACRO_2\" passed 3 arguments, but takes just 2" "" { target c++ } use_of_MACRO_2 } */
+  /* { dg-message "-: macro .MACRO_2. defined here" "" { target *-*-* } def_of_MACRO_2 } */
+  /* { dg-error "'MACRO_2' was not declared in this scope" "" { target c++ } use_of_MACRO_2 } */
+  /* { dg-bogus "had not yet been defined" "" { target *-*-* } use_of_MACRO_2 } */
+}
+
+#define MACRO_3
+void test_3 ()
+{
+  MACRO_3 (42);
+}
+
+#define MACRO_4(X,Y)
+void test_4 ()
+{
+  MACRO_4; /* { dg-line "use_of_MACRO_4" } */
+  /* { dg-error "'MACRO_4' was not declared in this scope" "" { target c++ } use_of_MACRO_4 } */
+}
diff --git a/gcc/testsuite/g++.dg/diagnostic/macro-arg-count.C b/gcc/testsuite/g++.dg/diagnostic/macro-arg-count.C
deleted file mode 100644
index 12b2dbd3be7..00000000000
--- a/gcc/testsuite/g++.dg/diagnostic/macro-arg-count.C
+++ /dev/null
@@ -1,51 +0,0 @@
-// { dg-options "-fdiagnostics-show-caret" }
-
-#define MACRO_1(X,Y)
-void test_1 ()
-{
-  MACRO_1(42); // { dg-line "use_of_MACRO_1" }
-  // { dg-error "macro \"MACRO_1\" requires 2 arguments, but only 1 given" "" { target *-*-* } use_of_MACRO_1 }
-  /* { dg-begin-multiline-output "" }
-   MACRO_1(42);
-             ^
-     { dg-end-multiline-output "" } */
-  // { dg-error "'MACRO_1' was not declared in this scope" "" { target *-*-* } use_of_MACRO_1 }
-  /* { dg-begin-multiline-output "" }
-   MACRO_1(42);
-   ^~~~~~~
-     { dg-end-multiline-output "" } */
-  // { dg-bogus "had not yet been defined" "" { target *-*-* } use_of_MACRO_1 }
-}
-
-#define MACRO_2(X,Y)
-void test_2 ()
-{
-  MACRO_2(1, 2, 3); // { dg-line "use_of_MACRO_2" }
-  // { dg-error "macro \"MACRO_2\" passed 3 arguments, but takes just 2" "" { target *-*-* } use_of_MACRO_2 }
-  /* { dg-begin-multiline-output "" }
-   MACRO_2(1, 2, 3);
-                  ^
-     { dg-end-multiline-output "" } */
-  // { dg-error "'MACRO_2' was not declared in this scope" "" { target *-*-* } use_of_MACRO_2 }
-  /* { dg-begin-multiline-output "" }
-   MACRO_2(1, 2, 3);
-   ^~~~~~~
-     { dg-end-multiline-output "" } */
-  // { dg-bogus "had not yet been defined" "" { target *-*-* } use_of_MACRO_2 }
-}
-
-#define MACRO_3
-void test_3 ()
-{
-  MACRO_3 (42);
-}
-
-#define MACRO_4(X,Y)
-void test_4 ()
-{
-  MACRO_4; // { dg-error "'MACRO_4' was not declared in this scope" }
-  /* { dg-begin-multiline-output "" }
-   MACRO_4;
-   ^~~~~~~
-     { dg-end-multiline-output "" } */
-}
diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index fe0dc8ddfe5..e240b2c7058 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/ChangeLog
@@ -1,3 +1,8 @@
+2018-10-11  David Malcolm  <dmalcolm@redhat.com>
+
+	* macro.c (_cpp_arguments_ok): If the argument count is wrong, add
+	a note showing the definition of the macro.
+
 2018-10-11  Nathan Sidwell  <nathan@acm.org>
 
 	* include/line-map.h (LINEMAPS_MACRO_LOWEST_LOCATION): Fix
diff --git a/libcpp/macro.c b/libcpp/macro.c
index 073816dd221..aacaf8c3020 100644
--- a/libcpp/macro.c
+++ b/libcpp/macro.c
@@ -964,6 +964,10 @@ _cpp_arguments_ok (cpp_reader *pfile, cpp_macro *macro, const cpp_hashnode *node
 	       "macro \"%s\" passed %u arguments, but takes just %u",
 	       NODE_NAME (node), argc, macro->paramc);
 
+  if (macro->line > RESERVED_LOCATION_COUNT)
+    cpp_error_at (pfile, CPP_DL_NOTE, macro->line, "macro \"%s\" defined here",
+		  NODE_NAME (node));
+
   return false;
 }