diff mbox series

[v2] Add new warning Wmissing-designated-initializers [PR39589]

Message ID 20240907211714.8665-1-mail@pfrost.me
State New
Headers show
Series [v2] Add new warning Wmissing-designated-initializers [PR39589] | expand

Commit Message

Peter Frost Sept. 7, 2024, 9:17 p.m. UTC 
v2 Patch:
	* adds proper changelog text
	* fixes typo in c.opt

Currently the behaviour of Wmissing-field-initializers is inconsistent
between C and C++. The C warning assumes that missing designated 
initializers are deliberate, and does not warn. The C++ warning does warn
for missing designated initializers.

This patch changes the behaviour of Wmissing-field-initializers to
universally not warn about missing designated initializers, and adds a new
warning for specifically for missing designated initializers.

NOTE TO MAINTAINERS: This is my first gcc contribution, so I don't have
git write access.

Successfully tested on x86_64-pc-linux-gnu.

	PR c/39589

gcc/c-family/ChangeLog:

	* c.opt: Added new option Wmissing-designated-initializers, enabled by
	Wextra

gcc/c/ChangeLog:

	* c-typeck.cc (pop_init_level): Generate warning for missing designated
	initializers rather than always ignore

gcc/cp/ChangeLog:

	* typeck2.cc (process_init_constructor_record): Add check if missing
	initializer is designated, warn as appropriate

gcc/testsuite/ChangeLog:

	* g++.dg/diagnostic/base.C: Change flags
	* gcc.dg/20011021-1.c: Fix test, missing designated initializers can
	generate a warning now
	* gcc.dg/missing-field-init-1.c: Change flags
	* gcc.dg/pr60784.c: Change flags
	* g++.dg/warn/missing-designated-initializers-1.C: New test.
	* g++.dg/warn/missing-designated-initializers-2.C: New test.
	* gcc.dg/missing-designated-initializers-1.c: New test.
	* gcc.dg/missing-designated-initializers-2.c: New test.


---
 gcc/c-family/c.opt                            |  4 +++
 gcc/c/c-typeck.cc                             | 36 +++++++++++--------
 gcc/cp/typeck2.cc                             | 20 ++++++++---
 gcc/testsuite/g++.dg/diagnostic/base.C        |  4 +--
 .../warn/missing-designated-initializers-1.C  | 11 ++++++
 .../warn/missing-designated-initializers-2.C  | 11 ++++++
 gcc/testsuite/gcc.dg/20011021-1.c             |  4 +--
 .../missing-designated-initializers-1.c       | 13 +++++++
 .../missing-designated-initializers-2.c       | 13 +++++++
 gcc/testsuite/gcc.dg/missing-field-init-1.c   |  2 +-
 gcc/testsuite/gcc.dg/pr60784.c                |  2 +-
 11 files changed, 96 insertions(+), 24 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/warn/missing-designated-initializers-1.C
 create mode 100644 gcc/testsuite/g++.dg/warn/missing-designated-initializers-2.C
 create mode 100644 gcc/testsuite/gcc.dg/missing-designated-initializers-1.c
 create mode 100644 gcc/testsuite/gcc.dg/missing-designated-initializers-2.c
diff mbox series

Patch

diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 491aa02e1a3..81e52f1417e 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -977,6 +977,10 @@  Wmissing-field-initializers
 C ObjC C++ ObjC++ Var(warn_missing_field_initializers) Warning EnabledBy(Wextra)
 Warn about missing fields in struct initializers.
 
+Wmissing-designated-initializers
+C ObjC C++ ObjC++ Var(warn_missing_designated_initializers) Warning EnabledBy(Wextra)
+Warn about missing designated initializers in struct initializers.
+
 Wmissing-format-attribute
 C ObjC C++ ObjC++ Warning Alias(Wsuggest-attribute=format)
 ;
diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index 094e41fa202..72b544e8f67 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -9795,7 +9795,7 @@  pop_init_level (location_t loc, int implicit,
     }
 
   /* Warn when some struct elements are implicitly initialized to zero.  */
-  if (warn_missing_field_initializers
+  if ((warn_missing_field_initializers || warn_missing_designated_initializers)
       && constructor_type
       && TREE_CODE (constructor_type) == RECORD_TYPE
       && constructor_unfilled_fields)
@@ -9806,21 +9806,29 @@  pop_init_level (location_t loc, int implicit,
 		   || integer_zerop (DECL_SIZE (constructor_unfilled_fields))))
 	  constructor_unfilled_fields = DECL_CHAIN (constructor_unfilled_fields);
 
-	if (constructor_unfilled_fields
-	    /* Do not warn if this level of the initializer uses member
-	       designators; it is likely to be deliberate.  */
-	    && !constructor_designated
-	    /* Do not warn about initializing with { 0 } or with { }.  */
-	    && !constructor_zeroinit)
-	  {
-	    if (warning_at (input_location, OPT_Wmissing_field_initializers,
+	  if (constructor_unfilled_fields
+	      /* Do not warn about initializing with { 0 } or with { }.  */
+	      && !constructor_zeroinit)
+	    {
+		if (!constructor_designated)
+		  {
+		    if (warning_at (input_location, OPT_Wmissing_field_initializers,
 			    "missing initializer for field %qD of %qT",
-			    constructor_unfilled_fields,
-			    constructor_type))
-	      inform (DECL_SOURCE_LOCATION (constructor_unfilled_fields),
+			    constructor_unfilled_fields, constructor_type))
+			  inform (DECL_SOURCE_LOCATION (constructor_unfilled_fields),
+			  "%qD declared here", constructor_unfilled_fields);
+		  }
+		else if (warn_missing_designated_initializers)
+		  {
+		    if (warning_at (
+			    input_location, OPT_Wmissing_designated_initializers,
+			    "missing designated initializer for field %qD of %qT",
+			    constructor_unfilled_fields, constructor_type))
+			  inform (DECL_SOURCE_LOCATION (constructor_unfilled_fields),
 		      "%qD declared here", constructor_unfilled_fields);
-	  }
-    }
+		  }
+		}
+	}
 
   /* Pad out the end of the structure.  */
   if (p->replacement_value.value)
diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc
index 30a6fbe95c9..6d21caf53d7 100644
--- a/gcc/cp/typeck2.cc
+++ b/gcc/cp/typeck2.cc
@@ -1822,8 +1822,14 @@  process_init_constructor_record (tree type, tree init, int nested, int flags,
 	  if ((complain & tf_warning)
 	      && !cp_unevaluated_operand
 	      && !EMPTY_CONSTRUCTOR_P (init))
-	    warning (OPT_Wmissing_field_initializers,
-		     "missing initializer for member %qD", field);
+	    {
+	      if (CONSTRUCTOR_IS_DESIGNATED_INIT (init))
+		    warning (OPT_Wmissing_designated_initializers,
+		    "missing designated initializer for member %qD", field);
+	      else
+		    warning (OPT_Wmissing_field_initializers,
+		    "missing initializer for member %qD", field);
+	    }
 	}
       else
 	{
@@ -1853,8 +1859,14 @@  process_init_constructor_record (tree type, tree init, int nested, int flags,
 	      && !cp_unevaluated_operand
 	      && !EMPTY_CONSTRUCTOR_P (init)
 	      && !is_really_empty_class (fldtype, /*ignore_vptr*/false))
-	    warning (OPT_Wmissing_field_initializers,
-		     "missing initializer for member %qD", field);
+	    {
+	      if (CONSTRUCTOR_IS_DESIGNATED_INIT (init))
+		    warning (OPT_Wmissing_designated_initializers,
+		      "missing designated initializer for member %qD", field);
+	      else
+		    warning (OPT_Wmissing_field_initializers,
+		      "missing initializer for member %qD", field);
+	    }
 
 	  if (!zero_init_p (fldtype) || skipped < 0)
 	    {
diff --git a/gcc/testsuite/g++.dg/diagnostic/base.C b/gcc/testsuite/g++.dg/diagnostic/base.C
index 1540414072e..d8c644f78f5 100644
--- a/gcc/testsuite/g++.dg/diagnostic/base.C
+++ b/gcc/testsuite/g++.dg/diagnostic/base.C
@@ -1,6 +1,6 @@ 
 // PR c++/110745
 // { dg-do compile { target c++17 } }
-// { dg-options "-Wmissing-field-initializers" }
+// { dg-options "-Wmissing-designated-initializers" }
 
 struct B { int i; };
 struct D : B {
@@ -11,6 +11,6 @@  struct D : B {
 int
 main ()
 {
-  D d = {.x=1, .y=2}; // { dg-warning "missing initializer for member .D::B." }
+  D d = {.x=1, .y=2}; // { dg-warning "missing designated initializer for member .D::B." }
   (void)d;
 }
diff --git a/gcc/testsuite/g++.dg/warn/missing-designated-initializers-1.C b/gcc/testsuite/g++.dg/warn/missing-designated-initializers-1.C
new file mode 100644
index 00000000000..86afafc5e9b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/missing-designated-initializers-1.C
@@ -0,0 +1,11 @@ 
+/* { dg-do compile } */
+/* { dg-options "-Wextra -Wmissing-designated-initializers" } */
+
+struct s { int a, b, c; };
+struct s s1 = { .a = 1, .b = 2, .c = 3 };
+struct s s2 = { .a = 1, .b = 2 }; /* { dg-warning "missing designated initializer" } */
+struct s s3 = { .a = 1 }; /* { dg-warning "missing designated initializer" } */
+
+struct s s6[] = { { .a = 1, .b = 2, .c = 3 }, { .a = 4 } }; /* { dg-warning "missing designated initializer" } */
+struct s s7[] = { { .a = 1 }, { .a = 2, .b = 3, .c = 4 } }; /* { dg-warning "missing designated initializer" } */
+struct s s8[] = { { 1, 2, 3 }, { .a = 4 } }; /* { dg-warning "missing designated initializer" } */
diff --git a/gcc/testsuite/g++.dg/warn/missing-designated-initializers-2.C b/gcc/testsuite/g++.dg/warn/missing-designated-initializers-2.C
new file mode 100644
index 00000000000..b47af7baac5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/missing-designated-initializers-2.C
@@ -0,0 +1,11 @@ 
+/* { dg-do compile } */
+/* { dg-options "-Wextra -Wno-missing-designated-initializers" } */
+
+struct s { int a, b, c; };
+struct s s1 = { .a = 1, .b = 2, .c = 3 };
+struct s s2 = { .a = 1, .b = 2 }; /* { dg-bogus "missing designated initializer" } */
+struct s s3 = { .a = 1 }; /* { dg-bogus "missing designated initializer" } */
+
+struct s s6[] = { { .a = 1, .b = 2, .c = 3 }, { .a = 4 } }; /* { dg-bogus "missing designated initializer" } */
+struct s s7[] = { { .a = 1 }, { .a = 2, .b = 3, .c = 4 } }; /* { dg-bogus "missing designated initializer" } */
+struct s s8[] = { { 1, 2, 3 }, { .a = 4 } }; /* { dg-bogus "missing designated initializer" } */
diff --git a/gcc/testsuite/gcc.dg/20011021-1.c b/gcc/testsuite/gcc.dg/20011021-1.c
index 2d567a75381..66964541d05 100644
--- a/gcc/testsuite/gcc.dg/20011021-1.c
+++ b/gcc/testsuite/gcc.dg/20011021-1.c
@@ -29,7 +29,7 @@  struct multilevel
 
 struct t T0 = { 1 };		/* { dg-warning "missing init" } */
 
-struct t T1 = { .a = 1 };	/* { dg-bogus "(missing|near) init" } */
+struct t T1 = { .a = 1 };	/* { dg-warning "missing designated initializer" } */
 
 union u U0 = { 1 };		/* { dg-warning "initialization of union" } */
 union u U1 = { .i = 1 };	/* { dg-bogus "initialization of union" } */
@@ -37,7 +37,7 @@  union u U1 = { .i = 1 };	/* { dg-bogus "initialization of union" } */
 struct multilevel M =
 {
   12,
-  { .b = 3 },			/* { dg-bogus "missing init" } */
+  { .b = 3 },			/* { dg-warning "missing designated initializer"  } */
   { 4 },			/* { dg-warning "initialization of union" } */
   { .n = 9 },			/* { dg-bogus "initialization of union" } */
   /* "string here" */
diff --git a/gcc/testsuite/gcc.dg/missing-designated-initializers-1.c b/gcc/testsuite/gcc.dg/missing-designated-initializers-1.c
new file mode 100644
index 00000000000..817386785f3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/missing-designated-initializers-1.c
@@ -0,0 +1,13 @@ 
+/* { dg-do compile } */
+/* { dg-options "-Wextra -Wmissing-designated-initializers" } */
+
+struct s { int a, b, c; };
+struct s s1 = { .a = 1, .b = 2, .c = 3 };
+struct s s2 = { .a = 1, .b = 2 }; /* { dg-warning "missing designated initializer" } */
+struct s s3 = { .a = 1 }; /* { dg-warning "missing designated initializer" } */
+struct s s4 = { .a = 1, 2 }; /* { dg-warning "missing designated initializer" } */
+struct s s5 = { .a = 1, 2, 3 }; /* { dg-bogus "missing designated initializer" } */
+
+struct s s6[] = { { .a = 1, .b = 2, .c = 3 }, { .a = 4 } }; /* { dg-warning "missing designated initializer" } */
+struct s s7[] = { { .a = 1 }, { .a = 2, .b = 3, .c = 4 } }; /* { dg-warning "missing designated initializer" } */
+struct s s8[] = { { 1, 2, 3 }, { .a = 4 } }; /* { dg-warning "missing designated initializer" } */
diff --git a/gcc/testsuite/gcc.dg/missing-designated-initializers-2.c b/gcc/testsuite/gcc.dg/missing-designated-initializers-2.c
new file mode 100644
index 00000000000..dc2c6bb51f3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/missing-designated-initializers-2.c
@@ -0,0 +1,13 @@ 
+/* { dg-do compile } */
+/* { dg-options "-Wextra -Wno-missing-designated-initializers" } */
+
+struct s { int a, b, c; };
+struct s s1 = { .a = 1, .b = 2, .c = 3 };
+struct s s2 = { .a = 1, .b = 2 }; /* { dg-bogus "missing designated initializer" } */
+struct s s3 = { .a = 1 }; /* { dg-bogus "missing designated initializer" } */
+struct s s4 = { .a = 1, 2 }; /* { dg-bogus "missing designated initializer" } */
+struct s s5 = { .a = 1, 2, 3 }; /* { dg-bogus "missing designated initializer" } */
+
+struct s s6[] = { { .a = 1, .b = 2, .c = 3 }, { .a = 4 } }; /* { dg-bogus "missing designated initializer" } */
+struct s s7[] = { { .a = 1 }, { .a = 2, .b = 3, .c = 4 } }; /* { dg-bogus "missing designated initializer" } */
+struct s s8[] = { { 1, 2, 3 }, { .a = 4 } }; /* { dg-bogus "missing designated initializer" } */
diff --git a/gcc/testsuite/gcc.dg/missing-field-init-1.c b/gcc/testsuite/gcc.dg/missing-field-init-1.c
index 5f32b021f0a..cd43fcc4f06 100644
--- a/gcc/testsuite/gcc.dg/missing-field-init-1.c
+++ b/gcc/testsuite/gcc.dg/missing-field-init-1.c
@@ -1,5 +1,5 @@ 
 /* { dg-do compile } */
-/* { dg-options "-Wextra -Wno-missing-field-initializers -std=c99" } */
+/* { dg-options "-Wextra -Wno-missing-field-initializers -Wno-missing-designated-initializers -std=c99" } */
 
 struct s { int a, b, c; };
 struct s s1 = { 1, 2, 3 };
diff --git a/gcc/testsuite/gcc.dg/pr60784.c b/gcc/testsuite/gcc.dg/pr60784.c
index 82b512f7c2e..60532831f4f 100644
--- a/gcc/testsuite/gcc.dg/pr60784.c
+++ b/gcc/testsuite/gcc.dg/pr60784.c
@@ -1,6 +1,6 @@ 
 /* PR c/60784 */
 /* { dg-do compile } */
-/* { dg-options "-Wextra -std=c99" } */
+/* { dg-options "-Wextra -Wno-missing-designated-initializers -std=c99" } */
 
 struct A { int i, j; };
 struct B { struct A a; } b1 = { .a.i = 1, .a.j = 1 };