[PATCH] D28148: [Sema] Suppress warnings for C's zero initializer

[S. Gilles via Phabricator via cfe-commits]

sgilles updated the summary for this revision.
sgilles updated this revision to Diff 82638.
sgilles added a comment.

Instead of adding a language option to distinguish C, negatively check
against C++.


https://reviews.llvm.org/D28148

Files:
  lib/Sema/SemaInit.cpp
  test/Sema/zero-initializer.c


Index: test/Sema/zero-initializer.c
===================================================================
--- /dev/null
+++ test/Sema/zero-initializer.c
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -std=c99 -Wmissing-field-initializers -Wmissing-braces
+
+struct foo {
+  int x;
+  int y;
+};
+
+struct bar {
+  struct foo a;
+  struct foo b;
+};
+
+int main(void)
+{
+  struct foo f = { 0 }; // expected-no-diagnostics
+  struct foo g = { 9 }; // expected-warning {{missing field 'y' initializer}}
+  struct foo h = { 9, 9 }; // expected-no-diagnostics
+  struct bar i = { 0 }; // expected-no-diagnostics
+  struct bar j = { 0, 0 }; // expected-warning {{suggest braces around initialization of suboject}} expected-warning {{missing field 'b' initializer}}
+  struct bar k = { { 9, 9 }, { 9, 9 } }; // expected-no-diagnostics
+  struct bar l = { { 9, 9 }, { 0 } }; // expected-no-diagnostics
+  struct bar m = { { 0 }, { 0 } }; // expected-no-diagnostics
+  struct bar n = { { 0 }, { 9, 9 } }; // expected-no-diagnostics
+  struct bar o = { { 9, 9 }, { 0 } }; // expected-no-diagnostics
+  struct bar p = { { 9 }, { 9, 9 } }; // expected-warning {{missing field 'y' initializer}}
+
+  return f.x + g.x + h.x + i.a.x + j.a.x + k.a.x + l.a.x + m.a.x + n.a.x +
+         o.a.x + p.a.x;
+}
Index: lib/Sema/SemaInit.cpp
===================================================================
--- lib/Sema/SemaInit.cpp
+++ lib/Sema/SemaInit.cpp
@@ -880,8 +880,19 @@
       StructuredSubobjectInitList->setRBraceLoc(EndLoc);
     }
 
+    bool MissingBracesOkay = false;
+
+    if (!SemaRef.getLangOpts().CPlusPlus &&
+        StructuredSubobjectInitList->getNumInits() == 1) {
+      if (const IntegerLiteral *lit = dyn_cast<IntegerLiteral>(StructuredSubobjectInitList->getInit(0))) {
+        if (lit->getValue() == 0) {
+          MissingBracesOkay = true;
+        }
+      }
+    }
+
     // Complain about missing braces.
-    if (T->isArrayType() || T->isRecordType()) {
+    if (!MissingBracesOkay && (T->isArrayType() || T->isRecordType())) {
       SemaRef.Diag(StructuredSubobjectInitList->getLocStart(),
                    diag::warn_missing_braces)
           << StructuredSubobjectInitList->getSourceRange()
@@ -1828,6 +1839,17 @@
   RecordDecl *RD = DeclType->getAs<RecordType>()->getDecl();
   RecordDecl::field_iterator FieldEnd = RD->field_end();
   bool CheckForMissingFields = true;
+
+  // Check if this is C's zero initializer { 0 }
+  if (!SemaRef.getLangOpts().CPlusPlus &&
+      IList->getNumInits() == 1) {
+    if (const IntegerLiteral *lit = dyn_cast<IntegerLiteral>(IList->getInit(0))) {
+      if (lit->getValue() == 0) {
+        CheckForMissingFields = false;
+      }
+    }
+  }
+
   while (Index < IList->getNumInits()) {
     Expr *Init = IList->getInit(Index);
 


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