Use function prototypes when appropriate; NFC

This prepares the clang-tools-extra project for -Wstrict-prototypes
being enabled by default.

clang-tools-extra/test/clang-reorder-fields/PlainCStructFieldsOrder.c

@@ -7,7 +7,7 @@ struct Foo {
   int w;        // CHECK-NEXT: {{^  const int\* x}}
 };
 
-int main() {
+int main(void) {
   const int x = 13;
   struct Foo foo = { &x, 0, 1.29, 17 }; // CHECK: {{^  struct Foo foo = { 1.29, 17, 0, &x };}} 
   return 0;

clang-tools-extra/test/clang-tidy/checkers/android-comparison-in-temp-failure-retry-custom-macro.c

@@ -18,10 +18,10 @@
     __z;                               \
   })
 
-int foo();
+int foo(void);
 int bar(int a);
 
-void with_custom_macro() {
+void with_custom_macro(void) {
   MY_TEMP_FAILURE_RETRY(foo());
   MY_TEMP_FAILURE_RETRY(foo() == 1);
   // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: top-level comparison in MY_TEMP_FAILURE_RETRY
@@ -33,7 +33,7 @@ void with_custom_macro() {
   // CHECK-MESSAGES: :[[@LINE-1]]:49: warning: top-level comparison in MY_TEMP_FAILURE_RETRY
 }
 
-void with_other_custom_macro() {
+void with_other_custom_macro(void) {
   MY_OTHER_TEMP_FAILURE_RETRY(foo());
   MY_OTHER_TEMP_FAILURE_RETRY(foo() == 1);
   // CHECK-MESSAGES: :[[@LINE-1]]:37: warning: top-level comparison in MY_OTHER_TEMP_FAILURE_RETRY

clang-tools-extra/test/clang-tidy/checkers/android-comparison-in-temp-failure-retry.c

@@ -9,10 +9,10 @@
     __z;                                                                       \
   })
 
-int foo();
+int foo(void);
 int bar(int a);
 
-void test() {
+void test(void) {
   int i;
   TEMP_FAILURE_RETRY((i = foo()));
   TEMP_FAILURE_RETRY(foo());
@@ -86,7 +86,7 @@ void test() {
 }
 
 // Be sure that it works inside of things like loops, if statements, etc.
-void control_flow() {
+void control_flow(void) {
   do {
     if (TEMP_FAILURE_RETRY(foo())) {
     }
@@ -105,7 +105,7 @@ void control_flow() {
   // CHECK-MESSAGES: :[[@LINE-1]]:37: warning: top-level comparison in TEMP_FAILURE_RETRY
 }
 
-void with_nondependent_variable_type() {
+void with_nondependent_variable_type(void) {
 #undef TEMP_FAILURE_RETRY
 #define TEMP_FAILURE_RETRY(x)                                                  \
   ({                                                                           \
@@ -126,7 +126,7 @@ void with_nondependent_variable_type() {
 
 // I can't find a case where TEMP_FAILURE_RETRY is implemented like this, but if
 // we can cheaply support it, I don't see why not.
-void obscured_temp_failure_retry() {
+void obscured_temp_failure_retry(void) {
 #undef TEMP_FAILURE_RETRY
 #define IMPL(x)                                                                \
   ({                                                                           \

clang-tools-extra/test/clang-tidy/checkers/bugprone-assert-side-effect.m

@@ -1,6 +1,6 @@
 // RUN: %check_clang_tidy %s bugprone-assert-side-effect %t
 
-int abort();
+int abort(void);
 
 @interface NSObject
 @end
@@ -46,7 +46,7 @@ int abort();
 }
 @end
 
-void foo() {
+void foo(void) {
   int x = 0;
   NSCAssert((++x) == 1, @"Ugh.");
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: side effect in NSCAssert() condition discarded in release builds [bugprone-assert-side-effect]

clang-tools-extra/test/clang-tidy/checkers/bugprone-branch-clone-macro-crash.c

@@ -8,7 +8,7 @@ int y = 1;
   else if (c)   \
     d = b;
 
-f() {
+void f(void) {
   // CHECK-MESSAGES: warning: repeated branch in conditional chain [bugprone-branch-clone]
   a(x, y)
 }

clang-tools-extra/test/clang-tidy/checkers/bugprone-easily-swappable-parameters-relatedness.c

@@ -7,7 +7,7 @@
 // RUN:     {key: bugprone-easily-swappable-parameters.ModelImplicitConversions, value: 0}, \
 // RUN:     {key: bugprone-easily-swappable-parameters.SuppressParametersUsedTogether, value: 1}, \
 // RUN:     {key: bugprone-easily-swappable-parameters.NamePrefixSuffixSilenceDissimilarityTreshold, value: 0} \
-// RUN:  ]}' -- -x c
+// RUN:  ]}' -- -Wno-strict-prototypes -x c
 
 int myprint();
 int add(int X, int Y);

clang-tools-extra/test/clang-tidy/checkers/bugprone-easily-swappable-parameters.c

@@ -7,7 +7,7 @@
 // RUN:     {key: bugprone-easily-swappable-parameters.ModelImplicitConversions, value: 0}, \
 // RUN:     {key: bugprone-easily-swappable-parameters.SuppressParametersUsedTogether, value: 0}, \
 // RUN:     {key: bugprone-easily-swappable-parameters.NamePrefixSuffixSilenceDissimilarityTreshold, value: 0} \
-// RUN:  ]}' -- -x c
+// RUN:  ]}' -- -Wno-strict-prototypes -x c
 
 #define bool _Bool
 #define true 1

clang-tools-extra/test/clang-tidy/checkers/bugprone-not-null-terminated-result-memcpy-safe-other.c

@@ -13,7 +13,7 @@
 // False positive suppression.
 //===----------------------------------------------------------------------===//
 
-void good_memcpy_known_src() {
+void good_memcpy_known_src(void) {
   char dest[13];
   char src[] = "foobar";
   memcpy(dest, src, sizeof(src));
@@ -69,7 +69,7 @@ void good_memcpy_variable_array(int dest_length) {
   strcpy(dst02, "foobarbazqux");
 }
 
-void bad_memcpy_equal_src_length_and_length() {
+void bad_memcpy_equal_src_length_and_length(void) {
   char dest03[13];
   const char *src = "foobarbazqux";
   memcpy(dest03, src, 12);
@@ -77,7 +77,7 @@ void bad_memcpy_equal_src_length_and_length() {
   // CHECK-FIXES: strcpy(dest03, src);
 }
 
-void good_memcpy_equal_src_length_and_length() {
+void good_memcpy_equal_src_length_and_length(void) {
   char dst03[13];
   const char *src = "foobarbazqux";
   strcpy(dst03, src);
@@ -98,7 +98,7 @@ void good_memcpy_dest_size_overflows(const char *src) {
   strcpy(dst04, src);
 }
 
-void bad_memcpy_macro() {
+void bad_memcpy_macro(void) {
   char dest05[SRC_LENGTH];
   memcpy(dest05, SRC, SRC_LENGTH);
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: the result from calling 'memcpy' is not null-terminated [bugprone-not-null-terminated-result]
@@ -106,7 +106,7 @@ void bad_memcpy_macro() {
   // CHECK-FIXES-NEXT: strcpy(dest05, SRC);
 }
 
-void good_memcpy_macro() {
+void good_memcpy_macro(void) {
   char dst05[SRC_LENGTH + 1];
   strcpy(dst05, SRC);
 }

clang-tools-extra/test/clang-tidy/checkers/bugprone-reserved-identifier-c.c

@@ -2,9 +2,9 @@
 
 // in C, double underscores are fine except at the beginning
 
-void foo__();
-void f__o__o();
-void f_________oo();
-void __foo();
+void foo__(void);
+void f__o__o(void);
+void f_________oo(void);
+void __foo(void);
 // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: declaration uses identifier '__foo', which is a reserved identifier [bugprone-reserved-identifier]
-// CHECK-FIXES: {{^}}void foo();{{$}}
+// CHECK-FIXES: {{^}}void foo(void);{{$}}

clang-tools-extra/test/clang-tidy/checkers/bugprone-signal-handler-minimal.c

@@ -25,7 +25,7 @@ void handler_good(int) {
   signal(0, SIG_DFL);
 }
 
-void test() {
+void test(void) {
   signal(SIGINT, handler_bad1);
   signal(SIGINT, handler_bad2);
   signal(SIGINT, handler_good);

clang-tools-extra/test/clang-tidy/checkers/bugprone-signal-handler-posix.c

@@ -23,7 +23,7 @@ void handler_good(int) {
   memcpy((void*)10, (const void*)20, 1);
 }
 
-void test() {
+void test(void) {
   signal(SIGINT, handler_good);
   signal(SIGINT, handler_bad);
 }

clang-tools-extra/test/clang-tidy/checkers/bugprone-signal-handler.c

@@ -13,7 +13,7 @@ int printf(const char *, ...);
 typedef void (*sighandler_t)(int);
 sighandler_t signal(int signum, sighandler_t handler);
 
-void f_extern();
+void f_extern(void);
 
 void handler_printf(int) {
   printf("1234");
@@ -22,7 +22,7 @@ void handler_printf(int) {
   // CHECK-NOTES: :[[@LINE+4]]:18: note: function 'handler_printf' registered here as signal handler
 }
 
-void test_printf() {
+void test_printf(void) {
   signal(SIGINT, handler_printf);
 }
 
@@ -33,11 +33,11 @@ void handler_extern(int) {
   // CHECK-NOTES: :[[@LINE+4]]:18: note: function 'handler_extern' registered here as signal handler
 }
 
-void test_extern() {
+void test_extern(void) {
   signal(SIGINT, handler_extern);
 }
 
-void f_ok() {
+void f_ok(void) {
   abort();
 }
 
@@ -45,11 +45,11 @@ void handler_ok(int) {
   f_ok();
 }
 
-void test_ok() {
+void test_ok(void) {
   signal(SIGINT, handler_ok);
 }
 
-void f_bad() {
+void f_bad(void) {
   printf("1234");
   // CHECK-NOTES: :[[@LINE-1]]:3: warning: 'printf' may not be asynchronous-safe; calling it from a signal handler may be dangerous [bugprone-signal-handler]
   // CHECK-NOTES: :[[@LINE-2]]:3: note: function 'printf' called here from 'f_bad'
@@ -61,11 +61,11 @@ void handler_bad(int) {
   f_bad();
 }
 
-void test_bad() {
+void test_bad(void) {
   signal(SIGINT, handler_bad);
 }
 
-void f_bad1() {
+void f_bad1(void) {
   printf("1234");
   // CHECK-NOTES: :[[@LINE-1]]:3: warning: 'printf' may not be asynchronous-safe; calling it from a signal handler may be dangerous [bugprone-signal-handler]
   // CHECK-NOTES: :[[@LINE-2]]:3: note: function 'printf' called here from 'f_bad1'
@@ -74,7 +74,7 @@ void f_bad1() {
   // CHECK-NOTES: :[[@LINE+13]]:18: note: function 'handler_bad1' registered here as signal handler
 }
 
-void f_bad2() {
+void f_bad2(void) {
   f_bad1();
 }
 
@@ -83,7 +83,7 @@ void handler_bad1(int) {
   f_bad1();
 }
 
-void test_bad1() {
+void test_bad1(void) {
   signal(SIGINT, handler_bad1);
 }
 
@@ -104,7 +104,7 @@ void handler_false_condition(int) {
   // CHECK-NOTES: :[[@LINE+4]]:18: note: function 'handler_false_condition' registered here as signal handler
 }
 
-void test_false_condition() {
+void test_false_condition(void) {
   signal(SIGINT, handler_false_condition);
 }
 
@@ -121,11 +121,11 @@ void handler_multiple_calls(int) {
   // first 'f_extern' call found only
 }
 
-void test_multiple_calls() {
+void test_multiple_calls(void) {
   signal(SIGINT, handler_multiple_calls);
 }
 
-void f_recursive();
+void f_recursive(void);
 
 void handler_recursive(int) {
   f_recursive();
@@ -133,7 +133,7 @@ void handler_recursive(int) {
   // first 'printf' call (in other function) found only
 }
 
-void f_recursive() {
+void f_recursive(void) {
   f_extern();
   // CHECK-NOTES: :[[@LINE-1]]:3: warning: 'f_extern' may not be asynchronous-safe; calling it from a signal handler may be dangerous [bugprone-signal-handler]
   // CHECK-NOTES: :[[@LINE-2]]:3: note: function 'f_extern' called here from 'f_recursive'
@@ -147,11 +147,11 @@ void f_recursive() {
   handler_recursive(2);
 }
 
-void test_recursive() {
+void test_recursive(void) {
   signal(SIGINT, handler_recursive);
 }
 
-void f_multiple_paths() {
+void f_multiple_paths(void) {
   printf("");
   // CHECK-NOTES: :[[@LINE-1]]:3: warning: 'printf' may not be asynchronous-safe; calling it from a signal handler may be dangerous [bugprone-signal-handler]
   // CHECK-NOTES: :[[@LINE-2]]:3: note: function 'printf' called here from 'f_multiple_paths'
@@ -164,21 +164,21 @@ void handler_multiple_paths(int) {
   f_multiple_paths();
 }
 
-void test_multiple_paths() {
+void test_multiple_paths(void) {
   signal(SIGINT, handler_multiple_paths);
 }
 
 void handler_function_pointer(int) {
-  void (*fp)() = f_extern;
+  void (*fp)(void) = f_extern;
   // Call with function pointer is not evalauted by the check.
   (*fp)();
 }
 
-void test_function_pointer() {
+void test_function_pointer(void) {
   signal(SIGINT, handler_function_pointer);
 }
 
-void test_other() {
+void test_other(void) {
   signal(SIGINT, handler_abort);
   signal(SIGINT, handler_signal);
 

clang-tools-extra/test/clang-tidy/checkers/bugprone-spuriously-wake-up-functions.c

@@ -161,4 +161,4 @@ void consume_list_element(void) {
   for (;; list_c.next == NULL)
     cnd_timedwait(&condition_c, &lock, &ts);
 }
-int main() { return 0; }
+int main(void) { return 0; }

clang-tools-extra/test/clang-tidy/checkers/bugprone-suspicious-memory-comparison.c

@@ -64,13 +64,13 @@ int flp37_c_compliant(const struct S2 *s1, const struct S2 *s2) {
   // no-warning
 }
 
-void Test_Float() {
+void Test_Float(void) {
   float a, b;
   memcmp(&a, &b, sizeof(float));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'float' which does not have a unique object representation; consider comparing the values manually
 }
 
-void TestArray_Float() {
+void TestArray_Float(void) {
   float a[3], b[3];
   memcmp(a, b, sizeof(a));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'float' which does not have a unique object representation; consider comparing the values manually
@@ -88,12 +88,12 @@ struct NoPadding {
   int y;
 };
 
-void Test_NoPadding() {
+void Test_NoPadding(void) {
   struct NoPadding a, b;
   memcmp(&a, &b, sizeof(struct NoPadding));
 }
 
-void TestArray_NoPadding() {
+void TestArray_NoPadding(void) {
   struct NoPadding a[3], b[3];
   memcmp(a, b, 3 * sizeof(struct NoPadding));
 }
@@ -103,7 +103,7 @@ struct TrailingPadding {
   char c;
 };
 
-void Test_TrailingPadding() {
+void Test_TrailingPadding(void) {
   struct TrailingPadding a, b;
   memcmp(&a, &b, sizeof(struct TrailingPadding));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'struct TrailingPadding' which does not have a unique object representation; consider comparing the members of the object manually
@@ -117,7 +117,7 @@ struct TrailingPadding2 {
   char c;
 };
 
-void Test_TrailingPadding2() {
+void Test_TrailingPadding2(void) {
   struct TrailingPadding2 a, b;
   memcmp(&a, &b, 2 * sizeof(int)); // no-warning: not comparing entire object
   memcmp(&a, &b, sizeof(struct TrailingPadding2));
@@ -129,13 +129,13 @@ void Test_UnknownCount(size_t count) {
   memcmp(&a, &b, count); // no-warning: unknown count value
 }
 
-void Test_ExplicitVoidCast() {
+void Test_ExplicitVoidCast(void) {
   struct TrailingPadding a, b;
   memcmp((void *)&a, (void *)&b,
          sizeof(struct TrailingPadding)); // no-warning: explicit cast
 }
 
-void TestArray_TrailingPadding() {
+void TestArray_TrailingPadding(void) {
   struct TrailingPadding a[3], b[3];
   memcmp(a, b, 3 * sizeof(struct TrailingPadding));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'struct TrailingPadding' which does not have a unique object representation; consider comparing the members of the object manually
@@ -146,7 +146,7 @@ struct InnerPadding {
   int i;
 };
 
-void Test_InnerPadding() {
+void Test_InnerPadding(void) {
   struct InnerPadding a, b;
   memcmp(&a, &b, sizeof(struct InnerPadding));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'struct InnerPadding' which does not have a unique object representation; consider comparing the members of the object manually
@@ -157,7 +157,7 @@ struct Bitfield_TrailingPaddingBytes {
   int y : 6;
 };
 
-void Test_Bitfield_TrailingPaddingBytes() {
+void Test_Bitfield_TrailingPaddingBytes(void) {
   struct Bitfield_TrailingPaddingBytes a, b;
   memcmp(&a, &b, sizeof(struct S));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'struct Bitfield_TrailingPaddingBytes' which does not have a unique object representation; consider comparing the members of the object manually
@@ -168,7 +168,7 @@ struct Bitfield_TrailingPaddingBits {
   int y : 20;
 };
 
-void Test_Bitfield_TrailingPaddingBits() {
+void Test_Bitfield_TrailingPaddingBits(void) {
   struct Bitfield_TrailingPaddingBits a, b;
   memcmp(&a, &b, sizeof(struct Bitfield_TrailingPaddingBits));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'struct Bitfield_TrailingPaddingBits' which does not have a unique object representation; consider comparing the members of the object manually
@@ -180,7 +180,7 @@ struct Bitfield_InnerPaddingBits {
   char y : 8;
 };
 
-void Test_Bitfield_InnerPaddingBits() {
+void Test_Bitfield_InnerPaddingBits(void) {
   struct Bitfield_InnerPaddingBits a, b;
   memcmp(&a, &b, sizeof(struct Bitfield_InnerPaddingBits));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'struct Bitfield_InnerPaddingBits' which does not have a unique object representation; consider comparing the members of the object manually
@@ -195,7 +195,7 @@ struct Bitfield_NoPadding {
 _Static_assert(sizeof(struct Bitfield_NoPadding) == sizeof(int),
                "Bit-fields should line up perfectly");
 
-void Test_Bitfield_NoPadding() {
+void Test_Bitfield_NoPadding(void) {
   struct Bitfield_NoPadding a, b;
   memcmp(&a, &b, sizeof(struct Bitfield_NoPadding)); // no-warning
 }
@@ -205,7 +205,7 @@ struct Bitfield_TrailingUnnamed {
   int : 0;
 };
 
-void Bitfield_TrailingUnnamed() {
+void Bitfield_TrailingUnnamed(void) {
   struct Bitfield_TrailingUnnamed a, b;
   memcmp(&a, &b, 2 * sizeof(int));                         // no-warning
   memcmp(&a, &b, sizeof(struct Bitfield_TrailingUnnamed)); // no-warning
@@ -220,7 +220,7 @@ struct PaddingAfterUnion {
   int y;
 };
 
-void Test_PaddingAfterUnion() {
+void Test_PaddingAfterUnion(void) {
   struct PaddingAfterUnion a, b;
   memcmp(&a, &b, sizeof(struct PaddingAfterUnion));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'struct PaddingAfterUnion' which does not have a unique object representation; consider comparing the members of the object manually
@@ -235,7 +235,7 @@ struct Union_NoPadding {
   int y;
 };
 
-void Test_Union_NoPadding() {
+void Test_Union_NoPadding(void) {
   struct Union_NoPadding a, b;
   memcmp(&a, &b, 2 * sizeof(int));
   memcmp(&a, &b, sizeof(struct Union_NoPadding));
@@ -250,7 +250,7 @@ union UnionWithPaddingInNestedStruct {
   } x;
 };
 
-void Test_UnionWithPaddingInNestedStruct() {
+void Test_UnionWithPaddingInNestedStruct(void) {
   union UnionWithPaddingInNestedStruct a, b;
   memcmp(&a, &b, sizeof(union UnionWithPaddingInNestedStruct));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'union UnionWithPaddingInNestedStruct' which does not have a unique object representation; consider comparing the members of the object manually
@@ -261,7 +261,7 @@ struct PaddingInNested {
   char y;
 };
 
-void Test_PaddingInNested() {
+void Test_PaddingInNested(void) {
   struct PaddingInNested a, b;
   memcmp(&a, &b, sizeof(struct PaddingInNested));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'struct PaddingInNested' which does not have a unique object representation; consider comparing the members of the object manually
@@ -275,7 +275,7 @@ struct PaddingAfterNested {
   int y;
 };
 
-void Test_PaddingAfterNested() {
+void Test_PaddingAfterNested(void) {
   struct PaddingAfterNested a, b;
   memcmp(&a, &b, sizeof(struct PaddingAfterNested));
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'struct PaddingAfterNested' which does not have a unique object representation; consider comparing the members of the object manually
@@ -285,7 +285,7 @@ struct AtomicMember {
   _Atomic(int) x;
 };
 
-void Test_AtomicMember() {
+void Test_AtomicMember(void) {
   // FIXME: this is a false positive as the list of objects with unique object
   // representations is incomplete.
   struct AtomicMember a, b;

clang-tools-extra/test/clang-tidy/checkers/bugprone-suspicious-memset-usage.c

@@ -4,7 +4,7 @@ void *memset(void *, int, __SIZE_TYPE__);
 void *memset(void *);
 // CHECK-MESSAGES: :[[@LINE-1]]:7: error: conflicting types for 'memset'
 
-void test() {
+void test(void) {
   // no crash
   memset(undefine);
   // CHECK-MESSAGES: :[[@LINE-1]]:10: error: use of undeclared identifier

clang-tools-extra/test/clang-tidy/checkers/bugprone-suspicious-string-compare.c

@@ -8,7 +8,7 @@ static const char A[] = "abc";
 
 int strcmp(const char *, const char *);
 
-int test_warning_patterns() {
+int test_warning_patterns(void) {
   if (strcmp(A, "a"))
     return 0;
   // CHECK-MESSAGES: [[@LINE-2]]:7: warning: function 'strcmp' is called without explicitly comparing result [bugprone-suspicious-string-compare]
@@ -42,7 +42,7 @@ int test_warning_patterns() {
   // CHECK-FIXES: if (strcmp(A, "a") == 0)
 }
 
-void test_structure_patterns() {
+void test_structure_patterns(void) {
   if (strcmp(A, "a")) {}
   // CHECK-MESSAGES: [[@LINE-1]]:7: warning: function 'strcmp' is called without explicitly comparing result
   // CHECK-FIXES: if (strcmp(A, "a") != 0) {}
@@ -56,7 +56,7 @@ void test_structure_patterns() {
   // CHECK-FIXES: for (;strcmp(A, "a") != 0;) {}
 }
 
-int test_valid_patterns() {
+int test_valid_patterns(void) {
   // The following cases are valid.
   if (strcmp(A, "a") < 0) return 0;
   if (strcmp(A, "a") == 0) return 0;

clang-tools-extra/test/clang-tidy/checkers/cert-err33-c.c

@@ -2,14 +2,14 @@
 
 typedef __SIZE_TYPE__ size_t;
 void *aligned_alloc(size_t alignment, size_t size);
-void test_aligned_alloc() {
+void test_aligned_alloc(void) {
   aligned_alloc(2, 10);
   // CHECK-NOTES: [[@LINE-1]]:3: warning: the value returned by this function should be used
   // CHECK-NOTES: [[@LINE-2]]:3: note: cast the expression to void to silence this warning
 }
 
 long strtol(const char *restrict nptr, char **restrict endptr, int base);
-void test_strtol() {
+void test_strtol(void) {
   strtol("123", 0, 10);
   // CHECK-NOTES: [[@LINE-1]]:3: warning: the value returned by this function should be used
   // CHECK-NOTES: [[@LINE-2]]:3: note: cast the expression to void to silence this warning
@@ -17,7 +17,7 @@ void test_strtol() {
 
 typedef char wchar_t;
 int wscanf_s(const wchar_t *restrict format, ...);
-void test_wscanf_s() {
+void test_wscanf_s(void) {
   int Val;
   wscanf_s("%i", &Val);
   // CHECK-NOTES: [[@LINE-1]]:3: warning: the value returned by this function should be used

clang-tools-extra/test/clang-tidy/checkers/cert-limited-randomness.c

@@ -1,9 +1,9 @@
 // RUN: %check_clang_tidy %s cert-msc30-c %t
 
 extern int rand(void);
-int nonrand();
+int nonrand(void);
 
-int cTest() {
+int cTest(void) {
   int i = rand();
   // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: rand() has limited randomness [cert-msc30-c]
 

clang-tools-extra/test/clang-tidy/checkers/cert-msc32-c.c

@@ -4,7 +4,7 @@ void srand(int seed);
 typedef int time_t;
 time_t time(time_t *t);
 
-void f() {
+void f(void) {
   srand(1);
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: random number generator seeded with a constant value will generate a predictable sequence of values [cert-msc32-c]
 
@@ -17,7 +17,7 @@ void f() {
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: random number generator seeded with a disallowed source of seed value will generate a predictable sequence of values [cert-msc32-c]
 }
 
-void g() {
+void g(void) {
   typedef int user_t;
   user_t a = 1;
   srand(a);

clang-tools-extra/test/clang-tidy/checkers/google-runtime-int.c

@@ -1,6 +1,6 @@
 // RUN: clang-tidy -checks=-*,google-runtime-int %s -- -x c 2>&1 | not grep 'warning:\|error:'
 
-long a();
+long a(void);
 
 long b(long x);
 
@@ -22,6 +22,6 @@ short bar(const short q, unsigned short w) {
   return q;
 }
 
-void qux() {
+void qux(void) {
   short port;
 }

clang-tools-extra/test/clang-tidy/checkers/linuxkernel-must-check-errs.c

@@ -10,7 +10,7 @@ int  __must_check IS_ERR_OR_NULL(const void *ptr);
 void * __must_check ERR_CAST(const void *ptr);
 int  __must_check PTR_ERR_OR_ZERO(const void *ptr);
 
-void f() {
+void f(void) {
   ERR_PTR(0);
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: result from function 'ERR_PTR' is unused
   PTR_ERR((void *)0);
@@ -24,18 +24,18 @@ out:
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: result from function 'PTR_ERR_OR_ZERO' is unused
 }
 
-void *f1() {
+void *f1(void) {
   return ERR_PTR(0);
 }
 
-long f2() {
+long f2(void) {
   if (IS_ERR((void *)0)) {
     return PTR_ERR((void *)0);
   }
   return -1;
 }
 
-void f3() {
+void f3(void) {
   f1();
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: result from function 'f1' is unused but represents an error value
   f2();

clang-tools-extra/test/clang-tidy/checkers/misc-static-assert.c

@@ -1,7 +1,7 @@
 // RUN: %check_clang_tidy %s misc-static-assert %t -- -- -std=c11
 // RUN: clang-tidy %s -checks=-*,misc-static-assert -- -std=c99 | count 0
 
-void abort() {}
+void abort(void) {}
 #ifdef NDEBUG
 #define assert(x) 1
 #else

clang-tools-extra/test/clang-tidy/checkers/misc-unused-parameters.c

@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s misc-unused-parameters %t -- -- -xc
+// RUN: %check_clang_tidy %s misc-unused-parameters %t -- -- -Wno-strict-prototypes -xc
 
 // Basic removal
 // =============

clang-tools-extra/test/clang-tidy/checkers/modernize-redundant-void-arg.c

@@ -1,4 +1,4 @@
-// RUN: clang-tidy -checks=-*,modernize-redundant-void-arg %s -- -x c | count 0
+// RUN: clang-tidy -checks=-*,modernize-redundant-void-arg %s -- -Wno-strict-prototypes -x c | count 0
 
 #define NULL 0
 
@@ -38,7 +38,7 @@ void (*(*returns_fn_returns_fn_void_void(void))(void))(void) {
   return NULL;
 }
 
-void bar() {
+void bar(void) {
   int i;
   int *pi = NULL;
   void *pv = (void *) pi;

clang-tools-extra/test/clang-tidy/checkers/objc-assert-equals.m

@@ -1,10 +1,10 @@
 // RUN: %check_clang_tidy %s objc-assert-equals %t -- -- -I %S/Inputs/objc-assert
 #include "XCTestAssertions.h"
 // Can't reference NSString directly so we use this getStr() instead.
-__typeof(@"abc") getStr() {
+__typeof(@"abc") getStr(void) {
   return @"abc";
 }
-void foo() {
+void foo(void) {
   XCTAssertEqual(getStr(), @"abc");
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use XCTAssertEqualObjects for comparing objects
   // CHECK-FIXES: XCTAssertEqualObjects(getStr(), @"abc");

clang-tools-extra/test/clang-tidy/checkers/objc-nsinvocation-argument-lifetime.m

@@ -29,9 +29,9 @@ void foo(NSInvocation *Invocation) {
   // CHECK-FIXES: __unsafe_unretained id Arg5;
   id ReturnValue;
   // CHECK-FIXES: __unsafe_unretained id ReturnValue;
-  void (^BlockArg1)();
-  // CHECK-FIXES: __unsafe_unretained void (^BlockArg1)();
-  __unsafe_unretained void (^BlockArg2)();
+  void (^BlockArg1)(void);
+  // CHECK-FIXES: __unsafe_unretained void (^BlockArg1)(void);
+  __unsafe_unretained void (^BlockArg2)(void);
   int IntVar;
   struct Foo Bar;
 

clang-tools-extra/test/clang-tidy/checkers/openmp-use-default-none.cpp

@@ -20,7 +20,7 @@ void n0(const int a) {
 
 // 'parallel' directive can have 'default' clause, but said clause is not
 // specified, diagnosed.
-void p0_0() {
+void p0_0(void) {
 #pragma omp parallel
   ;
   // CHECK-NOTES: :[[@LINE-2]]:1: warning: OpenMP directive 'parallel' does not specify 'default' clause, consider specifying 'default(none)' clause
@@ -28,14 +28,14 @@ void p0_0() {
 
 // 'parallel' directive can have 'default' clause, and said clause specified,
 // with 'none' kind, all good.
-void p0_1() {
+void p0_1(void) {
 #pragma omp parallel default(none)
   ;
 }
 
 // 'parallel' directive can have 'default' clause, and said clause specified,
 // but with 'shared' kind, which is not 'none', diagnose.
-void p0_2() {
+void p0_2(void) {
 #pragma omp parallel default(shared)
   ;
   // CHECK-NOTES: :[[@LINE-2]]:1: warning: OpenMP directive 'parallel' specifies 'default(shared)' clause, consider using 'default(none)' clause instead
@@ -44,7 +44,7 @@ void p0_2() {
 
 // 'parallel' directive can have 'default' clause, and said clause specified,
 // but with 'firstprivate' kind, which is not 'none', diagnose.
-void p0_3() {
+void p0_3(void) {
 #pragma omp parallel default(firstprivate)
   ;
   // CHECK-NOTES: :[[@LINE-2]]:1: warning: OpenMP directive 'parallel' specifies 'default(firstprivate)' clause, consider using 'default(none)' clause instead
@@ -55,7 +55,7 @@ void p0_3() {
 
 // 'task' directive can have 'default' clause, but said clause is not
 // specified, diagnosed.
-void p1_0() {
+void p1_0(void) {
 #pragma omp task
   ;
   // CHECK-NOTES: :[[@LINE-2]]:1: warning: OpenMP directive 'task' does not specify 'default' clause, consider specifying 'default(none)' clause
@@ -63,14 +63,14 @@ void p1_0() {
 
 // 'task' directive can have 'default' clause, and said clause specified,
 // with 'none' kind, all good.
-void p1_1() {
+void p1_1(void) {
 #pragma omp task default(none)
   ;
 }
 
 // 'task' directive can have 'default' clause, and said clause specified,
 // but with 'shared' kind, which is not 'none', diagnose.
-void p1_2() {
+void p1_2(void) {
 #pragma omp task default(shared)
   ;
   // CHECK-NOTES: :[[@LINE-2]]:1: warning: OpenMP directive 'task' specifies 'default(shared)' clause, consider using 'default(none)' clause instead
@@ -79,7 +79,7 @@ void p1_2() {
 
 // 'task' directive can have 'default' clause, and said clause specified,
 // but with 'firstprivate' kind, which is not 'none', diagnose.
-void p1_3() {
+void p1_3(void) {
 #pragma omp task default(firstprivate)
   ;
   // CHECK-NOTES: :[[@LINE-2]]:1: warning: OpenMP directive 'task' specifies 'default(firstprivate)' clause, consider using 'default(none)' clause instead
@@ -90,7 +90,7 @@ void p1_3() {
 
 // 'teams' directive can have 'default' clause, but said clause is not
 // specified, diagnosed.
-void p2_0() {
+void p2_0(void) {
 #pragma omp target
 #pragma omp teams
   ;
@@ -99,7 +99,7 @@ void p2_0() {
 
 // 'teams' directive can have 'default' clause, and said clause specified,
 // with 'none' kind, all good.
-void p2_1() {
+void p2_1(void) {
 #pragma omp target
 #pragma omp teams default(none)
   ;
@@ -107,7 +107,7 @@ void p2_1() {
 
 // 'teams' directive can have 'default' clause, and said clause specified,
 // but with 'shared' kind, which is not 'none', diagnose.
-void p2_2() {
+void p2_2(void) {
 #pragma omp target
 #pragma omp teams default(shared)
   ;
@@ -117,7 +117,7 @@ void p2_2() {
 
 // 'teams' directive can have 'default' clause, and said clause specified,
 // but with 'firstprivate' kind, which is not 'none', diagnose.
-void p2_3() {
+void p2_3(void) {
 #pragma omp target
 #pragma omp teams default(firstprivate)
   ;

clang-tools-extra/test/clang-tidy/checkers/readability-isolate-declaration.c

@@ -1,6 +1,6 @@
 // RUN: %check_clang_tidy %s readability-isolate-declaration %t
 
-void c_specific() {
+void c_specific(void) {
   void (*signal(int sig, void (*func)(int)))(int);
   int i = sizeof(struct S { int i; });
   int j = sizeof(struct T { int i; }), k;

clang-tools-extra/test/clang-tidy/checkers/readability-redundant-declaration.c

@@ -16,16 +16,16 @@ extern int Buf[10]; // Buf[10]
 // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: redundant 'Buf' declaration
 // CHECK-FIXES: {{^}}// Buf[10]{{$}}
 
-static int f();
-static int f(); // f
+static int f(void);
+static int f(void); // f
 // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: redundant 'f' declaration
 // CHECK-FIXES: {{^}}// f{{$}}
-static int f() {}
+static int f(void) {}
 
-inline void g() {}
+inline void g(void) {}
 
-inline void g();
+inline void g(void);
 // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: redundant 'g' declaration
 
 // OK: Needed to emit an external definition.
-extern inline void g();
+extern inline void g(void);