[v2,2/2] LoongArch: add model attribute

diff --git a/gcc/config/loongarch/loongarch-protos.h b/gcc/config/loongarch/loongarch-protos.h
index cadaad7519c..77b2217247d 100644
--- a/gcc/config/loongarch/loongarch-protos.h
+++ b/gcc/config/loongarch/loongarch-protos.h
@@ -28,7 +28,12 @@  along with GCC; see the file COPYING3. If not see
 The symbol's value will be loaded directly from the GOT.
 SYMBOL_PCREL
- The symbol's value will be loaded directly from data section.
+ The symbol's value will be loaded directly from data section within
+ +/- 2GiB range.
+
+ SYMBOL_PCREL64
+ The symbol's value will be loaded directly from data section within
+ +/- 8EiB range.
 SYMBOL_TLS
 A thread-local symbol.
@@ -42,6 +47,7 @@  along with GCC; see the file COPYING3. If not see
 enum loongarch_symbol_type {
 SYMBOL_GOT_DISP,
 SYMBOL_PCREL,
+ SYMBOL_PCREL64,
 SYMBOL_TLS,
 SYMBOL_TLS_IE,
 SYMBOL_TLS_LE,
diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index 41d9cca6d31..d9061cdeee3 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -1633,8 +1633,11 @@  loongarch_rtx_constant_in_small_data_p (machine_mode mode)
 static enum loongarch_symbol_type
 loongarch_classify_symbol (const_rtx x)
 {
+ enum loongarch_symbol_type pcrel =
+ TARGET_CMODEL_EXTREME ? SYMBOL_PCREL64 : SYMBOL_PCREL;
+
 if (!SYMBOL_REF_P (x))
- return SYMBOL_PCREL;
+ return pcrel;
 if (SYMBOL_REF_TLS_MODEL (x))
 return SYMBOL_TLS;
@@ -1642,7 +1645,28 @@  loongarch_classify_symbol (const_rtx x)
 if (!loongarch_symbol_binds_local_p (x))
 return SYMBOL_GOT_DISP;
- return SYMBOL_PCREL;
+ tree t = SYMBOL_REF_DECL (x);
+ if (!t)
+ return pcrel;
+
+ t = lookup_attribute ("model", DECL_ATTRIBUTES (t));
+ if (!t)
+ return pcrel;
+
+ t = TREE_VALUE (TREE_VALUE (t));
+
+ /* loongarch_handle_model_attribute should reject other values. */
+ gcc_assert (TREE_CODE (t) == STRING_CST);
+
+ const char *model = TREE_STRING_POINTER (t);
+ if (strcmp (model, "normal") == 0)
+ return SYMBOL_PCREL;
+ if (strcmp (model, "extreme") == 0)
+ return SYMBOL_PCREL64;
+
+ /* loongarch_handle_model_attribute should reject unknown model
+ name. */
+ gcc_unreachable ();
 }
 /* Classify the base of symbolic expression X, given that X appears in
@@ -1695,6 +1719,7 @@  loongarch_symbolic_constant_p (rtx x, enum loongarch_symbol_type *symbol_type)
 case SYMBOL_TLSGD:
 case SYMBOL_TLSLDM:
 case SYMBOL_PCREL:
+ case SYMBOL_PCREL64:
 /* GAS rejects offsets outside the range [-2^31, 2^31-1]. */
 return sext_hwi (INTVAL (offset), 32) == INTVAL (offset);
@@ -1729,6 +1754,9 @@  loongarch_symbol_insns (enum loongarch_symbol_type type, machine_mode mode)
 case SYMBOL_TLSLDM:
 return 3;
+ case SYMBOL_PCREL64:
+ return 5;
+
 case SYMBOL_TLS:
 /* We don't treat a bare TLS symbol as a constant. */
 return 0;
@@ -1833,7 +1861,7 @@  loongarch_valid_offset_p (rtx x, machine_mode mode)
 return true;
 }
-/* Should a symbol of type SYMBOL_TYPE should be split in two? */
+/* Should a symbol of type SYMBOL_TYPE should be split in two or more? */
 bool
 loongarch_split_symbol_type (enum loongarch_symbol_type symbol_type)
@@ -1841,6 +1869,7 @@  loongarch_split_symbol_type (enum loongarch_symbol_type symbol_type)
 switch (symbol_type)
 {
 case SYMBOL_PCREL:
+ case SYMBOL_PCREL64:
 case SYMBOL_GOT_DISP:
 case SYMBOL_TLS_IE:
 case SYMBOL_TLS_LE:
@@ -2718,6 +2747,20 @@  loongarch_force_address (rtx x, machine_mode mode)
 return x;
 }
+static bool
+loongarch_symbol_extreme_p (enum loongarch_symbol_type type)
+{
+ switch (type)
+ {
+ case SYMBOL_PCREL:
+ return false;
+ case SYMBOL_PCREL64:
+ return true;
+ default:
+ return TARGET_CMODEL_EXTREME;
+ }
+}
+
 /* If MODE is MAX_MACHINE_MODE, ADDR appears as a move operand, otherwise
 it appears in a MEM of that mode. Return true if ADDR is a legitimate
 constant in that context and can be split into high and low parts.
@@ -2757,7 +2800,7 @@  loongarch_split_symbol (rtx temp, rtx addr, machine_mode mode, rtx *low_out)
 high = gen_rtx_HIGH (Pmode, copy_rtx (addr));
 high = loongarch_force_temporary (temp, high);
- if (TARGET_CMODEL_EXTREME && can_create_pseudo_p ())
+ if (loongarch_symbol_extreme_p (symbol_type) && can_create_pseudo_p ())
 {
 gcc_assert (TARGET_EXPLICIT_RELOCS);
@@ -2771,14 +2814,16 @@  loongarch_split_symbol (rtx temp, rtx addr, machine_mode mode, rtx *low_out)
 if (low_out)
 switch (symbol_type)
 {
- case SYMBOL_PCREL:
- {
- if (TARGET_CMODEL_EXTREME && can_create_pseudo_p ())
+ case SYMBOL_PCREL64:
+ if (can_create_pseudo_p ())
+ {
 *low_out = gen_rtx_PLUS (Pmode, high, temp1);
- else
- *low_out = gen_rtx_LO_SUM (Pmode, high, addr);
- break;
- }
+ break;
+ }
+ /* fall through */
+ case SYMBOL_PCREL:
+ *low_out = gen_rtx_LO_SUM (Pmode, high, addr);
+ break;
 case SYMBOL_GOT_DISP:
 /* SYMBOL_GOT_DISP symbols are loaded from the GOT. */
@@ -4745,22 +4790,23 @@  loongarch_print_operand_reloc (FILE *file, rtx op, bool hi64_part,
 bool hi_reloc)
 {
 const char *reloc;
+ enum loongarch_symbol_type symbol_type =
+ loongarch_classify_symbolic_expression (op);
- if (TARGET_CMODEL_EXTREME)
+ if (loongarch_symbol_extreme_p (symbol_type))
 gcc_assert (TARGET_EXPLICIT_RELOCS);
- switch (loongarch_classify_symbolic_expression (op))
+ switch (symbol_type)
 {
- case SYMBOL_PCREL:
+ case SYMBOL_PCREL64:
 if (hi64_part)
 {
- if (TARGET_CMODEL_EXTREME)
- reloc = hi_reloc ? "%pc64_hi12" : "%pc64_lo20";
- else
- gcc_unreachable ();
+ reloc = hi_reloc ? "%pc64_hi12" : "%pc64_lo20";
+ break;
 }
- else
- reloc = hi_reloc ? "%pc_hi20" : "%pc_lo12";
+ /* fall through */
+ case SYMBOL_PCREL:
+ reloc = hi_reloc ? "%pc_hi20" : "%pc_lo12";
 break;
 case SYMBOL_GOT_DISP:
@@ -6316,6 +6362,104 @@  loongarch_starting_frame_offset (void)
 return crtl->outgoing_args_size;
 }
+static tree
+loongarch_handle_model_attribute (tree *node, tree name, tree arg, int,
+ bool *no_add_attrs)
+{
+ tree decl = *node;
+ if (TREE_CODE (decl) == VAR_DECL)
+ {
+ if (DECL_THREAD_LOCAL_P (decl))
+ {
+ error_at (DECL_SOURCE_LOCATION (decl),
+ "%qE attribute cannot be specified for thread-local "
+ "variables", name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+ if (DECL_CONTEXT (decl)
+ && TREE_CODE (DECL_CONTEXT (decl)) == FUNCTION_DECL
+ && !TREE_STATIC (decl))
+ {
+ error_at (DECL_SOURCE_LOCATION (decl),
+ "%qE attribute cannot be specified for local "
+ "variables", name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+ if (DECL_REGISTER (decl))
+ {
+ error_at (DECL_SOURCE_LOCATION (decl),
+ "%qE attribute cannot be specified for register "
+ "variables", name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+ if (!TARGET_EXPLICIT_RELOCS)
+ {
+ error_at (DECL_SOURCE_LOCATION (decl),
+ "%qE attribute requires %s", name, "-mexplicit-relocs");
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+
+ arg = TREE_VALUE (arg);
+ if (TREE_CODE (arg) != STRING_CST)
+ {
+ error_at (DECL_SOURCE_LOCATION (decl),
+ "invalid argument of %qE attribute", name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+
+ const char *model = TREE_STRING_POINTER (arg);
+ if (strcmp (model, "normal") != 0
+ && strcmp (model, "extreme") != 0)
+ {
+ error_at (DECL_SOURCE_LOCATION (decl),
+ "invalid argument of %qE attribute", name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+
+ if (lookup_attribute ("model", DECL_ATTRIBUTES (decl)))
+ {
+ error_at (DECL_SOURCE_LOCATION (decl),
+ "multiple %qE attribute", name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+ }
+ else
+ {
+ warning (OPT_Wattributes, "%qE attribute ignored", name);
+ *no_add_attrs = true;
+ }
+ return NULL_TREE;
+}
+
+static const struct attribute_spec loongarch_attribute_table[] =
+{
+ /* { name, min_len, max_len, decl_req, type_req, fn_type_req,
+ affects_type_identity, handler, exclude } */
+ { "model", 1, 1, true, false, false, false,
+ loongarch_handle_model_attribute, NULL },
+ /* The last attribute spec is set to be NULL. */
+ {}
+};
+
+bool
+loongarch_use_anchors_for_symbol_p (const_rtx symbol)
+{
+ tree decl = SYMBOL_REF_DECL (symbol);
+
+ /* The section anchor optimization may break custom address model. */
+ if (decl && lookup_attribute ("model", DECL_ATTRIBUTES (decl)))
+ return false;
+
+ return default_use_anchors_for_symbol_p (symbol);
+}
+
 /* Initialize the GCC target structure. */
 #undef TARGET_ASM_ALIGNED_HI_OP
 #define TARGET_ASM_ALIGNED_HI_OP "\t.half\t"
@@ -6504,6 +6648,12 @@  loongarch_starting_frame_offset (void)
 #undef TARGET_HAVE_SPECULATION_SAFE_VALUE
 #define TARGET_HAVE_SPECULATION_SAFE_VALUE speculation_safe_value_not_needed
+#undef TARGET_ATTRIBUTE_TABLE
+#define TARGET_ATTRIBUTE_TABLE loongarch_attribute_table
+
+#undef TARGET_USE_ANCHORS_FOR_SYMBOL_P
+#define TARGET_USE_ANCHORS_FOR_SYMBOL_P loongarch_use_anchors_for_symbol_p
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 #include "gt-loongarch.h"
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 7fe7f8817cd..431811c7b26 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -7314,6 +7314,7 @@  attributes.
 * Blackfin Variable Attributes::
 * H8/300 Variable Attributes::
 * IA-64 Variable Attributes::
+* LoongArch Variable Attributes::
 * M32R/D Variable Attributes::
 * MeP Variable Attributes::
 * Microsoft Windows Variable Attributes::
@@ -8098,6 +8099,21 @@  defined by shared libraries.
 @end table
+@node LoongArch Variable Attributes
+@subsection LoongArch Variable Attributes
+
+One attribute is currently defined for the LoongArch.
+
+@table @code
+@item model("@var{name}")
+@cindex @code{model} variable attribute, LoongArch
+Use this attribute on the LoongArch to use a different code model for
+addressing this variable, than the code model specified by the global
+@option{-mcmodel} option. This attribute is mostly useful if a
+@code{section} attribute and/or a linker script will locate this object
+specially.
+@end table
+
 @node M32R/D Variable Attributes
 @subsection M32R/D Variable Attributes
diff --git a/gcc/testsuite/gcc.target/loongarch/attr-model-1.c b/gcc/testsuite/gcc.target/loongarch/attr-model-1.c
new file mode 100644
index 00000000000..916d715b98b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/attr-model-1.c
@@ -0,0 +1,6 @@ 
+/* { dg-do compile } */
+/* { dg-options "-mexplicit-relocs -mcmodel=normal -O2" } */
+/* { dg-final { scan-assembler-times "%pc64_hi12" 2 } } */
+
+#define ATTR_MODEL_TEST
+#include "attr-model-test.c"
diff --git a/gcc/testsuite/gcc.target/loongarch/attr-model-2.c b/gcc/testsuite/gcc.target/loongarch/attr-model-2.c
new file mode 100644
index 00000000000..a74c795ac3e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/attr-model-2.c
@@ -0,0 +1,6 @@ 
+/* { dg-do compile } */
+/* { dg-options "-mexplicit-relocs -mcmodel=extreme -O2" } */
+/* { dg-final { scan-assembler-times "%pc64_hi12" 3 } } */
+
+#define ATTR_MODEL_TEST
+#include "attr-model-test.c"
diff --git a/gcc/testsuite/gcc.target/loongarch/attr-model-diag.c b/gcc/testsuite/gcc.target/loongarch/attr-model-diag.c
new file mode 100644
index 00000000000..88beede74df
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/attr-model-diag.c
@@ -0,0 +1,7 @@ 
+/* { dg-do compile } */
+/* { dg-options "-mexplicit-relocs" } */
+
+__thread int x __attribute__((model("extreme"))); /* { dg-error "attribute cannot be specified for thread-local variables" } */
+register int y __asm__("tp") __attribute__((model("extreme"))); /* { dg-error "attribute cannot be specified for register variables" } */
+int z __attribute__((model(114))); /* { dg-error "invalid argument" } */
+int t __attribute__((model("good"))); /* { dg-error "invalid argument" } */
diff --git a/gcc/testsuite/gcc.target/loongarch/attr-model-test.c b/gcc/testsuite/gcc.target/loongarch/attr-model-test.c
new file mode 100644
index 00000000000..5b61a7af9c3
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/attr-model-test.c
@@ -0,0 +1,25 @@ 
+#ifdef ATTR_MODEL_TEST
+int x __attribute__((model("extreme")));
+int y __attribute__((model("normal")));
+int z;
+
+int
+test(void)
+{
+ return x + y + z;
+}
+
+/* The following will be used for kernel per-cpu storage implemention. */
+
+register char *per_cpu_base __asm__("r21");
+static int counter __attribute__((section(".data..percpu"), model("extreme")));
+
+void
+inc_counter(void)
+{
+ int *ptr = (int *)(per_cpu_base + (long)&counter);
+ (*ptr)++;
+}
+#endif
+
+int dummy;