d: Match function declarations of gcc built-ins from any module.

Declarations of recognised gcc built-in functions are now matched from
any module.  Previously, only the `core.stdc' package was scanned.

In addition to matching of the symbol, any user-applied `@attributes' or
`pragma(mangle)' name will be applied to the built-in decl as well.
Because there would now be no control over where built-in declarations
are coming from, the warning option `-Wbuiltin-declaration-mismatch' has
been implemented in the D front-end too.

gcc/d/ChangeLog:

	* d-builtins.cc: Include builtins.h.
	(gcc_builtins_libfuncs): Remove.
	(strip_type_modifiers): New function.
	(matches_builtin_type): New function.
	(covariant_with_builtin_type_p): New function.
	(maybe_set_builtin_1): Set front-end built-in if identifier matches
	gcc built-in name.  Apply user-specified attributes and assembler name
	overrides to the built-in.  Warn about built-in declaration mismatches.
	(d_builtin_function): Set IDENTIFIER_DECL_TREE of built-in functions.
	* d-compiler.cc (Compiler::onParseModule): Scan all modules for any
	identifiers that match built-in function names.
	* lang.opt (Wbuiltin-declaration-mismatch): New option.

gcc/testsuite/ChangeLog:

	* gdc.dg/Wbuiltin_declaration_mismatch.d: New test.
	* gdc.dg/builtins.d: New test.

2 files changed, 54 insertions, 0 deletions

diff --git a/gcc/testsuite/gdc.dg/Wbuiltin_declaration_mismatch.d b/gcc/testsuite/gdc.dg/Wbuiltin_declaration_mismatch.d
new file mode 100644
index 0000000..5340647
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/Wbuiltin_declaration_mismatch.d
@@ -0,0 +1,37 @@
+// { dg-do compile }
+// { dg-options "-Wbuiltin-declaration-mismatch" }
+
+extern(C):
+
+// Mismatched parameter lengths
+double tan();             // { dg-warning "\\\[-Wbuiltin-declaration-mismatch]" }
+
+// Mismatched variadic arguments
+int printf(const(char)*); // { dg-warning "\\\[-Wbuiltin-declaration-mismatch]" }
+
+// Mismatched return type
+void puts(char*);         // { dg-warning "\\\[-Wbuiltin-declaration-mismatch]" }
+
+// Mismatched return storage class
+ref int isalnum(int);     // { dg-warning "\\\[-Wbuiltin-declaration-mismatch]" }
+
+// Mismatched parameter type
+double sin(long);         // { dg-warning "\\\[-Wbuiltin-declaration-mismatch]" }
+
+// Mismatched parameter storage class
+double frexp(double, lazy int*); // { dg-warning "\\\[-Wbuiltin-declaration-mismatch]" }
+double log(ref double);          // { dg-warning "\\\[-Wbuiltin-declaration-mismatch]" }
+
+// Verify that storage classes don't affect covariance matching
+@trusted nothrow @nogc pure double fabs(double);
+
+// Verify inout is allowed instead of const
+inout(char)* strstr(return scope inout(char)*, scope const char*) pure;
+
+// Verify that FILE* is allowed as it is implicitly convertable to void*
+struct _IO_FILE{}
+alias FILE = shared(_IO_FILE);
+int fprintf(FILE*, scope const char*, scope const ...);
+
+// Verify integral types with same size are treated as if equivalent
+int putchar(dchar);
diff --git a/gcc/testsuite/gdc.dg/builtins.d b/gcc/testsuite/gdc.dg/builtins.d
new file mode 100644
index 0000000..21e3a1e
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/builtins.d
@@ -0,0 +1,17 @@
+// { dg-do compile }
+// { dg-options "-fdump-tree-original" }
+
+// { dg-final { scan-tree-dump " __builtin_sqrt " "original" } }
+extern(C) double sqrt(double);
+double test_sqrt(double a) { return sqrt(a); }
+
+// { dg-final { scan-tree-dump-not " __builtin_tan " "original" } }
+pragma(mangle, "tan")
+extern(C) double libc_tan(double);
+double test_tan(double a) { return libc_tan(a); }
+
+// { dg-final { scan-tree-dump " __builtin_malloc " "original" } }
+// { dg-final { scan-assembler "mangle_override" } }
+pragma(mangle, "mangle_override")
+extern(C) void *malloc(size_t);
+void* test_malloc(size_t a) { return malloc(a); }