PR c/c++/diagnostics/66098 Take -Werror into account when deciding what was the command-line status

[Manuel López-Ibáñez]

When I fixed PR59304, I forgot that a command-line warning can be also
an error if -Werror was enabled. This introduced a regression since
anything enabled in the command-line together with -Werror would get
initially classified as a warning when reaching the first #pragma GCC
diagnostic, and this will be the setting after a #pragma pop.

Options that appear as arguments of -W[no-]error= are not affected by
this since those are initially classified as errors/warnings even
before reaching the first #pragma, thus the pop sets them correctly
(before and after this patch). Nonetheless, the tests also check that
they work correctly.

Boot&regtested on x86_64-linux-gnu.

OK?


gcc/ChangeLog:

2015-07-29  Manuel López-Ibáñez  <m...@gcc.gnu.org>

    PR c/66098
    PR c/66711
    * diagnostic.c (diagnostic_classify_diagnostic): Take -Werror into
    account when deciding what was the command-line status.

gcc/testsuite/ChangeLog:

2015-07-29  Manuel López-Ibáñez  <m...@gcc.gnu.org>

    PR c/66098
    PR c/66711
    * gcc.dg/pragma-diag-3.c: New test.
    * gcc.dg/pragma-diag-4.c: New test.

Index: gcc/diagnostic.c
===================================================================
--- gcc/diagnostic.c    (revision 226312)
+++ gcc/diagnostic.c    (working copy)
@@ -694,13 +694,14 @@ diagnostic_classify_diagnostic (diagnost
       int i;
 
       /* Record the command-line status, so we can reset it back on DK_POP. */
       if (old_kind == DK_UNSPECIFIED)
        {
-         old_kind = context->option_enabled (option_index,
-                                             context->option_state)
-           ? DK_WARNING : DK_IGNORED;
+         old_kind = !context->option_enabled (option_index,
+                                              context->option_state)
+           ? DK_IGNORED : (context->warning_as_error_requested
+                           ? DK_ERROR: DK_WARNING);
          context->classify_diagnostic[option_index] = old_kind;
        }
 
       for (i = context->n_classification_history - 1; i >= 0; i --)
        if (context->classification_history[i].option == option_index)
Index: gcc/testsuite/gcc.dg/pragma-diag-3.c
===================================================================
--- gcc/testsuite/gcc.dg/pragma-diag-3.c        (revision 0)
+++ gcc/testsuite/gcc.dg/pragma-diag-3.c        (revision 0)
@@ -0,0 +1,72 @@
+/* { dg-do compile } */
+/* { dg-options "-Wswitch-enum -Wsign-compare -fstrict-overflow 
-Wstrict-overflow -Werror -Wno-error=switch-enum" } */
+/* PR c/66098 - #pragma diagnostic 'ignored' not fully undone by pop for 
strict-overflow 
+   PR c/66711 - GCC does not correctly restore diagnostic state after pragma 
GCC diagnostic pop with -Werror 
+*/
+/* { dg-message "warnings being treated as errors" "" {target "*-*-*"} 0 } */
+
+void testing2() {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstrict-overflow"
+  int j = 4;
+  j + 4 < j;
+#pragma GCC diagnostic pop
+}
+
+void testing3() {
+  int k = 4;
+  k + 4 < k; /* { dg-error "overflow" } */
+}
+
+int foo() {
+  testing2();
+  testing3();
+
+  return 0;
+}
+
+
+int bar()
+{
+  unsigned x = 0;
+  int y = 1;
+
+  /* generates an error - ok */
+  x += x < y ? 1 : 0; /* { dg-error "comparison" } */
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-compare"
+  /* generates no diagnostic - ok */
+  x += x < y ? 1 : 0;
+#pragma GCC diagnostic pop
+
+  x += x < y ? 1 : 0; /* { dg-error "comparison" } */
+
+  return x;
+}
+
+enum EE { ONE, TWO };
+
+int f (enum EE e)
+{
+  int r = 0;
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wswitch-enum"
+
+  switch (e)
+    {
+    case ONE:
+      r = 1;
+      break;
+    }
+#pragma GCC diagnostic pop
+
+  switch (e) /* { dg-warning "switch" } */
+    {
+    case ONE:
+      r = 1;
+      break;
+    }
+  return r;
+}
Index: gcc/testsuite/gcc.dg/pragma-diag-4.c
===================================================================
--- gcc/testsuite/gcc.dg/pragma-diag-4.c        (revision 0)
+++ gcc/testsuite/gcc.dg/pragma-diag-4.c        (revision 0)
@@ -0,0 +1,48 @@
+/* { dg-do compile } */
+/* { dg-options "-Wsign-compare -Werror=sign-compare -Werror=switch-enum" } */
+/* { dg-message "warnings being treated as errors" "" {target "*-*-*"} 0 } */
+
+int bar()
+{
+  unsigned x = 0;
+  int y = 1;
+
+  /* generates an error - ok */
+  x += x < y ? 1 : 0; /* { dg-error "comparison" } */
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-compare"
+  /* generates no diagnostic - ok */
+  x += x < y ? 1 : 0;
+#pragma GCC diagnostic pop
+
+  x += x < y ? 1 : 0; /* { dg-error "comparison" } */
+
+  return x;
+}
+
+enum EE { ONE, TWO };
+
+int f (enum EE e)
+{
+  int r = 0;
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wswitch-enum"
+
+  switch (e)
+    {
+    case ONE:
+      r = 1;
+      break;
+    }
+#pragma GCC diagnostic pop
+
+  switch (e) /* { dg-error "switch" } */
+    {
+    case ONE:
+      r = 1;
+      break;
+    }
+  return r;
+}