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8c79706e89
This caused a miscompile in Chrome (see crbug.com/908372) that's
illustrated by this small reduction:
static bool f(int *a, int *b) {
return !__builtin_constant_p(b - a) || (!(b - a));
}
int arr[] = {1,2,3};
bool g() {
return f(arr, arr + 3);
}
$ clang -O2 -S -emit-llvm a.cc -o -
g() should return true, but after r347417 it became false for some reason.
This also reverts the follow-up commits.
r347417:
> Re-Reinstate 347294 with a fix for the failures.
>
> Don't try to emit a scalar expression for a non-scalar argument to
> __builtin_constant_p().
>
> Third time's a charm!
r347446:
> The result of is.constant() is unsigned.
r347480:
> A __builtin_constant_p() returns 0 with a function type.
r347512:
> isEvaluatable() implies a constant context.
>
> Assume that we're in a constant context if we're asking if the expression can
> be compiled into a constant initializer. This fixes the issue where a
> __builtin_constant_p() in a compound literal was diagnosed as not being
> constant, even though it's always possible to convert the builtin into a
> constant.
r347531:
> A "constexpr" is evaluated in a constant context. Make sure this is reflected
> if a __builtin_constant_p() is a part of a constexpr.
llvm-svn: 347656
84 lines
2.9 KiB
C++
84 lines
2.9 KiB
C++
// RUN: %clang_analyze_cc1 -triple x86_64-apple-darwin10 -analyzer-checker=core,debug.ExprInspection %s -std=c++11 -verify
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void clang_analyzer_eval(bool);
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void clang_analyzer_warnIfReached();
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void testAddressof(int x) {
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clang_analyzer_eval(&x == __builtin_addressof(x)); // expected-warning{{TRUE}}
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}
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void testSize() {
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struct {
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int x;
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int y;
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char z;
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} object;
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clang_analyzer_eval(__builtin_object_size(&object.y, 0) == sizeof(object) - sizeof(int)); // expected-warning{{TRUE}}
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// Clang can't actually evaluate these builtin "calls", but importantly they don't actually evaluate the argument expression either.
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int i = 0;
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char buf[10];
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clang_analyzer_eval(__builtin_object_size(&buf[i++], 0) == sizeof(buf)); // expected-warning{{FALSE}}
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clang_analyzer_eval(__builtin_object_size(&buf[++i], 0) == sizeof(buf) - 1); // expected-warning{{FALSE}}
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clang_analyzer_eval(i == 0); // expected-warning{{TRUE}}
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}
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void test_assume_aligned_1(char *p) {
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char *q;
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q = (char*) __builtin_assume_aligned(p, 16);
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clang_analyzer_eval(p == q); // expected-warning{{TRUE}}
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}
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void test_assume_aligned_2(char *p) {
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char *q;
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q = (char*) __builtin_assume_aligned(p, 16, 8);
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clang_analyzer_eval(p == q); // expected-warning{{TRUE}}
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}
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void test_assume_aligned_3(char *p) {
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void *q;
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q = __builtin_assume_aligned(p, 16, 8);
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clang_analyzer_eval(p == q); // expected-warning{{TRUE}}
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}
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void test_assume_aligned_4(char *p) {
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char *q;
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q = (char*) __builtin_assume_aligned(p + 1, 16);
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clang_analyzer_eval(p == q); // expected-warning{{FALSE}}
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}
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void f(int i) {
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__builtin_assume(i < 10);
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clang_analyzer_eval(i < 15); // expected-warning {{TRUE}}
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}
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void g(int i) {
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if (i > 5) {
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__builtin_assume(i < 5);
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clang_analyzer_warnIfReached(); // Assumtion contradicts constraints.
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// We give up the analysis on this path.
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}
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}
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void test_constant_p() {
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int i = 1;
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const int j = 2;
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constexpr int k = 3;
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clang_analyzer_eval(__builtin_constant_p(42) == 1); // expected-warning {{TRUE}}
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clang_analyzer_eval(__builtin_constant_p(i) == 0); // expected-warning {{TRUE}}
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clang_analyzer_eval(__builtin_constant_p(j) == 1); // expected-warning {{TRUE}}
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clang_analyzer_eval(__builtin_constant_p(k) == 1); // expected-warning {{TRUE}}
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clang_analyzer_eval(__builtin_constant_p(i + 42) == 0); // expected-warning {{TRUE}}
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clang_analyzer_eval(__builtin_constant_p(j + 42) == 1); // expected-warning {{TRUE}}
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clang_analyzer_eval(__builtin_constant_p(k + 42) == 1); // expected-warning {{TRUE}}
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clang_analyzer_eval(__builtin_constant_p(" ") == 1); // expected-warning {{TRUE}}
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clang_analyzer_eval(__builtin_constant_p(test_constant_p) == 0); // expected-warning {{TRUE}}
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clang_analyzer_eval(__builtin_constant_p(k - 3) == 0); // expected-warning {{FALSE}}
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clang_analyzer_eval(__builtin_constant_p(k - 3) == 1); // expected-warning {{TRUE}}
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}
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