Allow using __attribute__((shared)) to place static variables in '.shared'
memory space.
Changes in v2:
- reword diagnostic message in nvptx_handle_shared_attribute to follow other
backends ("... attribute not allowed with auto storage class");
- reject explicit initialization of ".shared" memory variables;
- add testcases.
testsuite/
2016-05-06 Alexander Monakov <[email protected]>
* gcc.target/nvptx/decl-shared.c: New test.
* gcc.target/nvptx/decl-shared-init.c: New test.
gcc/
2016-05-06 Alexander Monakov <[email protected]>
* config/nvptx/nvptx.c (nvptx_encode_section_info): Diagnose explicit
static initialization of variables in .shared memory.
(nvptx_handle_shared_attribute): Reword diagnostic message.
2016-04-19 Alexander Monakov <[email protected]>
* doc/extend.texi (Nvidia PTX Variable Attributes): New section.
2016-01-17 Alexander Monakov <[email protected]>
* config/nvptx/nvptx.c (nvptx_encode_section_info): Handle "shared"
attribute.
(nvptx_handle_shared_attribute): New. Use it...
(nvptx_attribute_table): ... here (new entry).
diff --git a/gcc/config/nvptx/nvptx.c b/gcc/config/nvptx/nvptx.c
index 2d4dad1..e9e4d06 100644
--- a/gcc/config/nvptx/nvptx.c
+++ b/gcc/config/nvptx/nvptx.c
@@ -234,9 +224,17 @@ nvptx_encode_section_info (tree decl, rtx rtl, int first)
if (TREE_CONSTANT (decl))
area = DATA_AREA_CONST;
else if (TREE_CODE (decl) == VAR_DECL)
- /* TODO: This would be a good place to check for a .shared or
- other section name. */
- area = TREE_READONLY (decl) ? DATA_AREA_CONST : DATA_AREA_GLOBAL;
+ {
+ if (lookup_attribute ("shared", DECL_ATTRIBUTES (decl)))
+ {
+ area = DATA_AREA_SHARED;
+ if (DECL_INITIAL (decl))
+ error ("static initialization of variable %q+D in %<.shared%>"
+ " memory is not supported", decl);
+ }
+ else
+ area = TREE_READONLY (decl) ? DATA_AREA_CONST : DATA_AREA_GLOBAL;
+ }
SET_SYMBOL_DATA_AREA (XEXP (rtl, 0), area);
}
@@ -3805,12 +4025,36 @@ nvptx_handle_kernel_attribute (tree *node, tree name,
tree ARG_UNUSED (args),
return NULL_TREE;
}
+/* Handle a "shared" attribute; arguments as in
+ struct attribute_spec.handler. */
+
+static tree
+nvptx_handle_shared_attribute (tree *node, tree name, tree ARG_UNUSED (args),
+ int ARG_UNUSED (flags), bool *no_add_attrs)
+{
+ tree decl = *node;
+
+ if (TREE_CODE (decl) != VAR_DECL)
+ {
+ error ("%qE attribute only applies to variables", name);
+ *no_add_attrs = true;
+ }
+ else if (current_function_decl && !TREE_STATIC (decl))
+ {
+ error ("%qE attribute not allowed with auto storage class", name);
+ *no_add_attrs = true;
+ }
+
+ return NULL_TREE;
+}
+
/* Table of valid machine attributes. */
static const struct attribute_spec nvptx_attribute_table[] =
{
/* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler,
affects_type_identity } */
{ "kernel", 0, 0, true, false, false, nvptx_handle_kernel_attribute, false
},
+ { "shared", 0, 0, true, false, false, nvptx_handle_shared_attribute, false
},
{ NULL, 0, 0, false, false, false, NULL, false }
};
diff --git a/gcc/testsuite/gcc.target/nvptx/decl-shared-init.c
b/gcc/testsuite/gcc.target/nvptx/decl-shared-init.c
new file mode 100644
index 0000000..6a99b1c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/nvptx/decl-shared-init.c
@@ -0,0 +1 @@
+int var __attribute__((shared)) = 0; /* { dg-error "static initialization .*
not supported" } */
diff --git a/gcc/testsuite/gcc.target/nvptx/decl-shared.c
b/gcc/testsuite/gcc.target/nvptx/decl-shared.c
new file mode 100644
index 0000000..367075c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/nvptx/decl-shared.c
@@ -0,0 +1,14 @@
+static int v_internal __attribute__((shared,used));
+int v_common __attribute__((shared));
+int v_extdef __attribute__((shared,nocommon));
+extern int v_extdecl __attribute__((shared));
+
+int use()
+{
+ return v_extdecl;
+}
+
+/* { dg-final { scan-assembler "\[\r\n\]\[\t \]*.shared \[^,\r\n\]*v_internal"
} } */
+/* { dg-final { scan-assembler "\[\r\n\]\[\t \]*.weak .shared
\[^,\r\n\]*v_common" } } */
+/* { dg-final { scan-assembler "\[\r\n\]\[\t \]*.visible .shared
\[^,\r\n\]*v_extdef" } } */
+/* { dg-final { scan-assembler "\[\r\n\]\[\t \]*.extern .shared
\[^,\r\n\]*v_extdecl" } } */
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index e11ce4d..5eeb179 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -5469,6 +5469,7 @@ attributes.
* MeP Variable Attributes::
* Microsoft Windows Variable Attributes::
* MSP430 Variable Attributes::
+* Nvidia PTX Variable Attributes::
* PowerPC Variable Attributes::
* RL78 Variable Attributes::
* SPU Variable Attributes::
@@ -6099,6 +6100,20 @@ same name (@pxref{MSP430 Function Attributes}).
These attributes can be applied to both functions and variables.
@end table
+@node Nvidia PTX Variable Attributes
+@subsection Nvidia PTX Variable Attributes
+
+These variable attributes are supported by the Nvidia PTX back end:
+
+@table @code
+@item shared
+@cindex @code{shared} attribute, Nvidia PTX
+Use this attribute to place a variable in the @code{.shared} memory space.
+This memory space is private to each cooperative thread array; only threads
+within one thread block refer to the same instance of the variable.
+The runtime does not initialize variables in this memory space.
+@end table
+
@node PowerPC Variable Attributes
@subsection PowerPC Variable Attributes
