04364fb888
Check for struct members that are structs filled only with function pointers by recursively examining it. Since the lamba IsFunctionPointerOrForwardDecl cannot call itself directly, move it into a helper function, EntirelyFunctionPointers, so it can be called from the lambda. Add test for composite function pointer structs getting automatically randomized. Add more tests for validating automatic randomization vs explicitly annotated with "randomize_layout", and excluded with "no_randomize_layout". Reorder the "should we randomize?" "if" statement to check for enablement before checking for Record details. Fixes #138355
124 lines
3.8 KiB
C
124 lines
3.8 KiB
C
// RUN: %clang_cc1 -triple=x86_64-unknown-linux -frandomize-layout-seed=1234567890abcded \
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// RUN: -verify -fsyntax-only -Werror %s
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// NOTE: The current seed (1234567890abcded) is specifically chosen because it
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// uncovered a bug in diagnostics. With it the randomization of "t9" places the
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// "a" element at the end of the record. When that happens, the clang complains
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// about excessive initializers, which is confusing, because there aren't
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// excessive initializers. It should instead complain about using a
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// non-designated initializer on a raqndomized struct.
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// Initializing a randomized structure requires a designated initializer,
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// otherwise the element ordering will be off. The only exceptions to this rule
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// are:
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//
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// - A structure with only one element, and
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// - A structure initialized with "{0}".
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//
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// These are well-defined situations where the field ordering doesn't affect
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// the result.
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typedef void (*func_ptr)();
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void foo(void);
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void bar(void);
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void baz(void);
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void gaz(void);
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struct test {
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func_ptr a;
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func_ptr b;
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func_ptr c;
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func_ptr d;
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func_ptr e;
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func_ptr f;
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func_ptr g;
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} __attribute__((randomize_layout));
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struct test t1 = {}; // This should be fine per WG14 N2900 (in C23) + our extension handling of it in earlier modes
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struct test t2 = { 0 }; // This should also be fine per C99 6.7.8p19
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struct test t3 = { .f = baz, .b = bar, .g = gaz, .a = foo }; // Okay
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struct test t4 = { .a = foo, bar, baz }; // expected-error {{a randomized struct can only be initialized with a designated initializer}}
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struct other_test {
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func_ptr a;
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func_ptr b[3];
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func_ptr c;
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} __attribute__((randomize_layout));
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struct other_test t5 = { .a = foo, .b[0] = foo }; // Okay
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struct other_test t6 = { .a = foo, .b[0] = foo, bar, baz }; // Okay
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struct other_test t7 = { .a = foo, .b = { foo, bar, baz } }; // Okay
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struct other_test t8 = { baz, bar, gaz, foo }; // expected-error {{a randomized struct can only be initialized with a designated initializer}}
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struct other_test t9 = { .a = foo, .b[0] = foo, bar, baz, gaz }; // expected-error {{a randomized struct can only be initialized with a designated initializer}}
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struct empty_test {
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} __attribute__((randomize_layout));
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struct empty_test t10 = {}; // Okay
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struct degen_test {
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func_ptr a;
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} __attribute__((randomize_layout));
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struct degen_test t11 = { foo }; // Okay
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struct static_assert_test {
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int f;
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_Static_assert(sizeof(int) == 4, "oh no!");
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} __attribute__((randomize_layout));
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struct static_assert_test t12 = { 42 }; // Okay
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struct enum_decl_test {
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enum e { BORK = 42, FORK = 9 } f;
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} __attribute__((randomize_layout));
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struct enum_decl_test t13 = { BORK }; // Okay
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struct mixed {
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int a;
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short b;
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unsigned c;
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char d;
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} __attribute__((randomize_layout));
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struct mixed t14 = { 7 }; // expected-error {{a randomized struct can only be initialized with a designated initializer}}
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struct mixed t15 = { .b = 8 }; // Okay
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// This should be autodetected as randomized.
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struct funcs {
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func_ptr a;
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func_ptr b;
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func_ptr c;
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func_ptr d;
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};
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struct funcs t16 = { .c = foo }; // Okay
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struct funcs t17 = { foo }; // expected-error {{a randomized struct can only be initialized with a designated initializer}}
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// This should be forced off.
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struct funcs_unshuffled {
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func_ptr a;
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func_ptr b;
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func_ptr c;
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func_ptr d;
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} __attribute__((no_randomize_layout));
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struct funcs_unshuffled t18 = { .d = foo }; // Okay
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struct funcs_unshuffled t19 = { foo }; // Okay
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// This is still all function pointers.
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// https://github.com/llvm/llvm-project/issues/138355
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struct funcs_composite {
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func_ptr a;
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func_ptr b;
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struct funcs inner;
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func_ptr c;
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func_ptr d;
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};
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struct funcs_composite t20 = { .a = foo }; // Okay
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struct funcs_composite t21 = { .inner.c = foo }; // Okay
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struct funcs_composite t22 = { foo }; // expected-error {{a randomized struct can only be initialized with a designated initializer}}
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