[gcc r13-5720] amdgcn: Pass -mstack-size through to runtime

[gcc r13-5720] amdgcn: Pass -mstack-size through to runtime

[Andrew Stubbs]

https://gcc.gnu.org/g:45e01229af33a3dc3f124dcaec4b4ae11e9d07ce

commit r13-5720-g45e01229af33a3dc3f124dcaec4b4ae11e9d07ce
Author: Andrew Stubbs <ams@codesourcery.com>
Date:   Mon Feb 6 12:47:28 2023 +0000

    amdgcn: Pass -mstack-size through to runtime
    
    But only for the offload case.
    
    gcc/ChangeLog:
    
            * config/gcn/mkoffload.cc (gcn_stack_size): New global variable.
            (process_asm): Create a constructor for GCN_STACK_SIZE.
            (main): Parse the -mstack-size option.

Diff:
---
 gcc/config/gcn/mkoffload.cc | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/gcc/config/gcn/mkoffload.cc b/gcc/config/gcn/mkoffload.cc
index 9c262f974be..9493f89fec3 100644
--- a/gcc/config/gcn/mkoffload.cc
+++ b/gcc/config/gcn/mkoffload.cc
@@ -117,6 +117,8 @@ uint32_t elf_arch = EF_AMDGPU_MACH_AMDGCN_GFX803;  // Default GPU architecture.
 uint32_t elf_flags =
     (EF_AMDGPU_FEATURE_XNACK_ANY_V4 | EF_AMDGPU_FEATURE_SRAMECC_ANY_V4);
 
+static int gcn_stack_size = 0;  /* Zero means use default.  */
+
 /* Delete tempfiles.  */
 
 void
@@ -662,6 +664,18 @@ process_asm (FILE *in, FILE *out, FILE *cfile)
     }
   fprintf (cfile, "\n};\n\n");
 
+  /* Set the stack size if the user configured a value.  */
+  if (gcn_stack_size)
+    fprintf (cfile,
+	     "static __attribute__((constructor))\n"
+	     "void configure_stack_size (void)\n"
+	     "{\n"
+	     "  const char *val = getenv (\"GCN_STACK_SIZE\");\n"
+	     "  if (!val || val[0] == '\\0')\n"
+	     "    setenv (\"GCN_STACK_SIZE\", \"%d\", true);\n"
+	     "}\n\n",
+	     gcn_stack_size);
+
   obstack_free (&fns_os, NULL);
   for (i = 0; i < dims_count; i++)
     free (dims[i].name);
@@ -920,6 +934,10 @@ main (int argc, char **argv)
 	elf_arch = EF_AMDGPU_MACH_AMDGCN_GFX908;
       else if (strcmp (argv[i], "-march=gfx90a") == 0)
 	elf_arch = EF_AMDGPU_MACH_AMDGCN_GFX90a;
+#define STR "-mstack-size="
+      else if (startswith (argv[i], STR))
+	gcn_stack_size = atoi (argv[i] + strlen (STR));
+#undef STR
     }
 
   if (!(fopenacc ^ fopenmp))