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-rw-r--r--gcc/c-decl.c93
1 files changed, 75 insertions, 18 deletions
diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index 8825db1..0890a2a 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -3350,9 +3350,19 @@ start_decl (declarator, declspecs, initialized, attributes)
/* ANSI specifies that a tentative definition which is not merged with
a non-tentative definition behaves exactly like a definition with an
initializer equal to zero. (Section 3.7.2)
- -fno-common gives strict ANSI behavior. Usually you don't want it.
- This matters only for variables with external linkage. */
- if (!initialized && (! flag_no_common || ! TREE_PUBLIC (decl)))
+
+ -fno-common gives strict ANSI behavior, though this tends to break
+ a large body of code that grew up without this rule.
+
+ Thread-local variables are never common, since there's no entrenched
+ body of code to break, and it allows more efficient variable references
+ in the presense of dynamic linking. */
+
+ if (TREE_CODE (decl) == VAR_DECL
+ && !initialized
+ && TREE_PUBLIC (decl)
+ && !DECL_THREAD_LOCAL (decl)
+ && !flag_no_common)
DECL_COMMON (decl) = 1;
/* Set attributes here so if duplicate decl, will have proper attributes. */
@@ -3933,7 +3943,7 @@ grokdeclarator (declarator, declspecs, decl_context, initialized)
enum rid i = C_RID_CODE (id);
if ((int) i <= (int) RID_LAST_MODIFIER)
{
- if (i == RID_LONG && (specbits & (1 << (int) i)))
+ if (i == RID_LONG && (specbits & (1 << (int) RID_LONG)))
{
if (longlong)
error ("`long long long' is too long for GCC");
@@ -3947,6 +3957,19 @@ grokdeclarator (declarator, declspecs, decl_context, initialized)
}
else if (specbits & (1 << (int) i))
pedwarn ("duplicate `%s'", IDENTIFIER_POINTER (id));
+
+ /* Diagnose "__thread extern". Recall that this list
+ is in the reverse order seen in the text. */
+ if (i == RID_THREAD
+ && (specbits & (1 << (int) RID_EXTERN
+ | 1 << (int) RID_STATIC)))
+ {
+ if (specbits & 1 << (int) RID_EXTERN)
+ error ("`__thread' before `extern'");
+ else
+ error ("`__thread' before `static'");
+ }
+
specbits |= 1 << (int) i;
goto found;
}
@@ -4196,6 +4219,12 @@ grokdeclarator (declarator, declspecs, decl_context, initialized)
if (specbits & 1 << (int) RID_REGISTER) nclasses++;
if (specbits & 1 << (int) RID_TYPEDEF) nclasses++;
+ /* "static __thread" and "extern __thread" are allowed. */
+ if ((specbits & (1 << (int) RID_THREAD
+ | 1 << (int) RID_STATIC
+ | 1 << (int) RID_EXTERN)) == (1 << (int) RID_THREAD))
+ nclasses++;
+
/* Warn about storage classes that are invalid for certain
kinds of declarations (parameters, typenames, etc.). */
@@ -4205,7 +4234,8 @@ grokdeclarator (declarator, declspecs, decl_context, initialized)
&& (specbits
& ((1 << (int) RID_REGISTER)
| (1 << (int) RID_AUTO)
- | (1 << (int) RID_TYPEDEF))))
+ | (1 << (int) RID_TYPEDEF)
+ | (1 << (int) RID_THREAD))))
{
if (specbits & 1 << (int) RID_AUTO
&& (pedantic || current_binding_level == global_binding_level))
@@ -4214,8 +4244,10 @@ grokdeclarator (declarator, declspecs, decl_context, initialized)
error ("function definition declared `register'");
if (specbits & 1 << (int) RID_TYPEDEF)
error ("function definition declared `typedef'");
+ if (specbits & 1 << (int) RID_THREAD)
+ error ("function definition declared `__thread'");
specbits &= ~((1 << (int) RID_TYPEDEF) | (1 << (int) RID_REGISTER)
- | (1 << (int) RID_AUTO));
+ | (1 << (int) RID_AUTO) | (1 << (int) RID_THREAD));
}
else if (decl_context != NORMAL && nclasses > 0)
{
@@ -4238,7 +4270,7 @@ grokdeclarator (declarator, declspecs, decl_context, initialized)
}
specbits &= ~((1 << (int) RID_TYPEDEF) | (1 << (int) RID_REGISTER)
| (1 << (int) RID_AUTO) | (1 << (int) RID_STATIC)
- | (1 << (int) RID_EXTERN));
+ | (1 << (int) RID_EXTERN) | (1 << (int) RID_THREAD));
}
}
else if (specbits & 1 << (int) RID_EXTERN && initialized && ! funcdef_flag)
@@ -4249,12 +4281,25 @@ grokdeclarator (declarator, declspecs, decl_context, initialized)
else
error ("`%s' has both `extern' and initializer", name);
}
- else if (specbits & 1 << (int) RID_EXTERN && funcdef_flag
- && current_binding_level != global_binding_level)
- error ("nested function `%s' declared `extern'", name);
- else if (current_binding_level == global_binding_level
- && specbits & (1 << (int) RID_AUTO))
- error ("top-level declaration of `%s' specifies `auto'", name);
+ else if (current_binding_level == global_binding_level)
+ {
+ if (specbits & 1 << (int) RID_AUTO)
+ error ("top-level declaration of `%s' specifies `auto'", name);
+ }
+ else
+ {
+ if (specbits & 1 << (int) RID_EXTERN && funcdef_flag)
+ error ("nested function `%s' declared `extern'", name);
+ else if ((specbits & (1 << (int) RID_THREAD
+ | 1 << (int) RID_EXTERN
+ | 1 << (int) RID_STATIC))
+ == (1 << (int) RID_THREAD))
+ {
+ error ("function-scope `%s' implicitly auto and declared `__thread'",
+ name);
+ specbits &= ~(1 << (int) RID_THREAD);
+ }
+ }
}
/* Now figure out the structure of the declarator proper.
@@ -4842,6 +4887,8 @@ grokdeclarator (declarator, declspecs, decl_context, initialized)
pedwarn ("invalid storage class for function `%s'", name);
if (specbits & (1 << (int) RID_REGISTER))
error ("invalid storage class for function `%s'", name);
+ if (specbits & (1 << (int) RID_THREAD))
+ error ("invalid storage class for function `%s'", name);
/* Function declaration not at top level.
Storage classes other than `extern' are not allowed
and `extern' makes no difference. */
@@ -4934,22 +4981,32 @@ grokdeclarator (declarator, declspecs, decl_context, initialized)
pedwarn_with_decl (decl, "variable `%s' declared `inline'");
DECL_EXTERNAL (decl) = extern_ref;
+
/* At top level, the presence of a `static' or `register' storage
class specifier, or the absence of all storage class specifiers
makes this declaration a definition (perhaps tentative). Also,
the absence of both `static' and `register' makes it public. */
if (current_binding_level == global_binding_level)
{
- TREE_PUBLIC (decl)
- = !(specbits
- & ((1 << (int) RID_STATIC) | (1 << (int) RID_REGISTER)));
- TREE_STATIC (decl) = ! DECL_EXTERNAL (decl);
+ TREE_PUBLIC (decl) = !(specbits & ((1 << (int) RID_STATIC)
+ | (1 << (int) RID_REGISTER)));
+ TREE_STATIC (decl) = !extern_ref;
}
/* Not at top level, only `static' makes a static definition. */
else
{
TREE_STATIC (decl) = (specbits & (1 << (int) RID_STATIC)) != 0;
- TREE_PUBLIC (decl) = DECL_EXTERNAL (decl);
+ TREE_PUBLIC (decl) = extern_ref;
+ }
+
+ if (specbits & 1 << (int) RID_THREAD)
+ {
+ if (targetm.have_tls)
+ DECL_THREAD_LOCAL (decl) = 1;
+ else
+ /* A mere warning is sure to result in improper semantics
+ at runtime. Don't bother to allow this to compile. */
+ error ("thread-local storage not supported for this target");
}
}
generated by cgit v1.1 at 2025-06-01 09:48:46 +0000