[Fix] Customize warnings for missing built-in types

If we detect a built-in declaration for which we cannot derive a type
matching the pattern in the Builtins.def file, we currently emit a
warning that the respective header is needed. However, this is not
necessarily the behavior we want as it has no connection to the location
of the declaration (which can actually be in the header in question).
Instead, this warning is generated
  - if we could not build the type for the pattern on file (for some
    reason). Here we should make the reason explicit. The actual problem
    is otherwise circumvented as the warning is misleading, see [0] for
    an example.
  - if we could not build the type for the pattern because we do not
    have a type on record, possible since D55483, we should not emit any
    warning. See [1] for a legitimate problem.

This patch address both cases. For the "setjmp" family a new warning is
introduced and for built-ins without type on record, so far
"pthread_create", we do not emit the warning anymore.

Also see: PR40692

[0] https://lkml.org/lkml/2019/1/11/718
[1] https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=235583

Differential Revision: https://reviews.llvm.org/D58091

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@367387 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 4cf1b3449d6323129fbb584024611c5da7ff7138..28e407a3a22e7d6660b2d688879032d9fb57b017 100644 (file)
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -598,6 +598,10 @@ def ext_implicit_lib_function_decl : ExtWarn<
 def note_include_header_or_declare : Note<
   "include the header <%0> or explicitly provide a declaration for '%1'">;
 def note_previous_builtin_declaration : Note<"%0 is a builtin with type %1">;
+def warn_implicit_decl_no_jmp_buf
+    : Warning<"declaration of built-in function '%0' requires the declaration"
+    " of the 'jmp_buf' type, commonly provided in the header <setjmp.h>.">,
+      InGroup<DiagGroup<"incomplete-setjmp-declaration">>;
 def warn_implicit_decl_requires_sysheader : Warning<
   "declaration of built-in function '%1' requires inclusion of the header <%0>">,
   InGroup<BuiltinRequiresHeader>;

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index ced24805ed8bbfac2343036e215c60da9447ef7c..74c6316da6a1aee392f96866a2d0a39a8b55b0ad 100644 (file)
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1983,10 +1983,27 @@ NamedDecl *Sema::LazilyCreateBuiltin(IdentifierInfo *II, unsigned ID,
   ASTContext::GetBuiltinTypeError Error;
   QualType R = Context.GetBuiltinType(ID, Error);
   if (Error) {
-    if (ForRedeclaration)
-      Diag(Loc, diag::warn_implicit_decl_requires_sysheader)
-          << getHeaderName(Context.BuiltinInfo, ID, Error)
+    if (!ForRedeclaration)
+      return nullptr;
+
+    // If we have a builtin without an associated type we should not emit a
+    // warning when we were not able to find a type for it.
+    if (Error == ASTContext::GE_Missing_type)
+      return nullptr;
+
+    // If we could not find a type for setjmp it is because the jmp_buf type was
+    // not defined prior to the setjmp declaration.
+    if (Error == ASTContext::GE_Missing_setjmp) {
+      Diag(Loc, diag::warn_implicit_decl_no_jmp_buf)
           << Context.BuiltinInfo.getName(ID);
+      return nullptr;
+    }
+
+    // Generally, we emit a warning that the declaration requires the
+    // appropriate header.
+    Diag(Loc, diag::warn_implicit_decl_requires_sysheader)
+        << getHeaderName(Context.BuiltinInfo, ID, Error)
+        << Context.BuiltinInfo.getName(ID);
     return nullptr;
   }
 

diff --git a/test/Analysis/retain-release.m b/test/Analysis/retain-release.m
index ad79d72d1aa10d8225bf0231a9d42c6ce4f40267..e459fb7a0b8583d33dcd98022d7a4a312835d8e9 100644 (file)
--- a/test/Analysis/retain-release.m
+++ b/test/Analysis/retain-release.m
@@ -2,7 +2,7 @@
 // RUN: %clang_analyze_cc1 -triple x86_64-apple-darwin10\
 // RUN:     -analyzer-checker=core,osx.coreFoundation.CFRetainRelease\
 // RUN:     -analyzer-checker=osx.cocoa.ClassRelease,osx.cocoa.RetainCount\
-// RUN:     -analyzer-checker=debug.ExprInspection -fblocks -verify=expected,C %s\
+// RUN:     -analyzer-checker=debug.ExprInspection -fblocks -verify %s\
 // RUN:     -Wno-objc-root-class -analyzer-output=plist -o %t.objc.plist
 // RUN: %clang_analyze_cc1 -triple x86_64-apple-darwin10\
 // RUN:     -analyzer-checker=core,osx.coreFoundation.CFRetainRelease\
@@ -1231,7 +1231,7 @@ typedef __darwin_pthread_attr_t pthread_attr_t;
 typedef unsigned long __darwin_pthread_key_t;
 typedef __darwin_pthread_key_t pthread_key_t;
 
-int pthread_create(pthread_t *, const pthread_attr_t *,  // C-warning{{declaration of built-in function 'pthread_create' requires inclusion of the header <pthread.h>}}
+int pthread_create(pthread_t *, const pthread_attr_t *,
                    void *(*)(void *), void *);
 
 int pthread_setspecific(pthread_key_t key, const void *value);

diff --git a/test/Sema/builtin-setjmp.c b/test/Sema/builtin-setjmp.c
new file mode 100644 (file)
index 0000000..f8770d8
--- /dev/null
+++ b/test/Sema/builtin-setjmp.c
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify -DNO_JMP_BUF %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify %s
+
+#ifdef NO_JMP_BUF
+extern long setjmp(long *);   // expected-warning {{declaration of built-in function 'setjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>.}}
+#else
+typedef long jmp_buf;
+extern int setjmp(char);      // expected-warning@8 {{incompatible redeclaration of library function 'setjmp'}}
+                              // expected-note@8    {{'setjmp' is a builtin with type 'int (jmp_buf)' (aka 'int (long)')}}
+#endif

diff --git a/test/Sema/implicit-builtin-decl.c b/test/Sema/implicit-builtin-decl.c
index 3c2ff94984c0ff553ecebbd22fad7ce2cb6ff3c8..3a3dfa935ac1661ab737c19bc352c6cadbd9cb42 100644 (file)
--- a/test/Sema/implicit-builtin-decl.c
+++ b/test/Sema/implicit-builtin-decl.c
@@ -55,14 +55,17 @@ main(int argc, char *argv[])
 
 void snprintf() { }
 
-// PR8316
-void longjmp(); // expected-warning{{declaration of built-in function 'longjmp' requires inclusion of the header <setjmp.h>}}
+// PR8316 & PR40692
+void longjmp(); // expected-warning{{declaration of built-in function 'longjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>.}}
 
 extern float fmaxf(float, float);
 
 struct __jmp_buf_tag {};
-void sigsetjmp(struct __jmp_buf_tag[1], int); // expected-warning{{declaration of built-in function 'sigsetjmp' requires inclusion of the header <setjmp.h>}}
+void sigsetjmp(struct __jmp_buf_tag[1], int); // expected-warning{{declaration of built-in function 'sigsetjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>.}}
 
 // CHECK:     FunctionDecl {{.*}} <line:[[@LINE-2]]:1, col:44> col:6 sigsetjmp '
 // CHECK-NOT: FunctionDecl
 // CHECK:     ReturnsTwiceAttr {{.*}} <{{.*}}> Implicit
+
+// PR40692
+void pthread_create(); // no warning expected