ballet, sbpf loader: manually register entrypoint to calldests

address PR feedback

add unit test

incorrect makefile params

reformat test file

src/ballet/sbpf/Local.mk

@@ -2,5 +2,7 @@ $(call add-hdrs,fd_sbpf_instr.h fd_sbpf_loader.h fd_sbpf_opcodes.h)
 $(call add-objs,fd_sbpf_loader,fd_ballet)
 ifdef FD_HAS_HOSTED
 $(call make-unit-test,test_sbpf_load_prog,test_sbpf_load_prog,fd_ballet fd_util)
+$(call make-unit-test,test_sbpf_loader,test_sbpf_loader,fd_ballet fd_util)
+$(call run-unit-test,test_sbpf_loader)
 endif
 $(call make-fuzz-test,fuzz_sbpf_loader,fuzz_sbpf_loader,fd_ballet fd_util)

src/ballet/sbpf/fd_sbpf_loader.c

@@ -937,15 +937,17 @@ fd_sbpf_r_bpf_64_32( fd_sbpf_loader_t   const * loader,
     /* Register new entry */
     uint hash;
     if( name_len >= 10UL && 0==strncmp( name, "entrypoint", name_len ) ) {
-      /* TODO register entrypoint */
+      /* Skip insertion of "entrypoint" relocation entries to calldests. This
+         emulates Solana/Agave's behavior of unregistering these entries before
+         registering the entrypoint manually.
+         Entrypoint is registered in fd_sbpf_program_load.
+         Hash is still applied. */
       hash = 0x71e3cf81;
     } else {
       hash = fd_murmur3_32( &target_pc, 8UL, 0U );
+      if( FD_LIKELY( target_pc < (info->rodata_sz / 8UL ) ) )
+        fd_sbpf_calldests_insert( loader->calldests, target_pc );
     }
-
-    if( FD_LIKELY( target_pc < (info->rodata_sz / 8UL ) ) )
-      fd_sbpf_calldests_insert( loader->calldests, target_pc );
-
     V = (uint)hash;
   } else {
     /* FIXME Should cache Murmur hashes.
@@ -1028,7 +1030,6 @@ fd_sbpf_hash_calls( fd_sbpf_loader_t *    loader,
     ulong target_pc = (ulong)target_pc_s;
     REQUIRE( target_pc<insn_cnt );  /* bounds check target */
 
-    /* Derive hash and insert */
     fd_sbpf_calldests_insert( calldests, target_pc );
 
     /* Replace immediate with hash */
@@ -1191,6 +1192,9 @@ fd_sbpf_program_load( fd_sbpf_program_t *  prog,
   /* Load dynamic section */
   if( FD_UNLIKELY( (err=fd_sbpf_load_dynamic( &loader, elf, elf_sz ))!=0 ) )
     return err;
+
+  /* Register entrypoint to calldests. */
+  fd_sbpf_calldests_insert( prog->calldests, prog->entry_pc );
 
   /* Copy rodata segment */
   fd_memcpy( prog->rodata, elf->bin, prog->info.rodata_footprint );

src/ballet/sbpf/test_sbpf_loader.c

@@ -0,0 +1,80 @@
+#include "fd_sbpf_loader.h"
+#include "../../util/fd_util.h"
+
+uint const _syscalls[] = {
+  0xb6fc1a11, 0x686093bb, 0x207559bd, 0x5c2a3178, 0x52ba5096,
+  0x7ef088ca, 0x9377323c, 0x48504a38, 0x11f49d86, 0xd7793abb,
+  0x17e40350, 0x174c5122, 0xaa2607ca, 0xdd1c41a6, 0xd56b5fe9,
+  0x23a29a61, 0x3b97b73c, 0xbf7188f6, 0x717cc4a3, 0x434371f8,
+  0x5fdcde31, 0x3770fb22, 0xa22b9c85, 0xd7449092, 0x83f00e8f,
+  0xa226d3eb, 0x5d2245e4, 0x7317b434, 0xadb8efc8, 0x85532d94,
+  0U
+};
+
+#define LOAD_ELF(id) \
+  FD_IMPORT_BINARY( id##_elf, "src/ballet/sbpf/fixtures/" #id ".elf" );
+
+LOAD_ELF( duplicate_entrypoint_entry )
+
+/* Properties of duplicate_entrypoint_entry.elf we are testing:
+  * Two symbol entries with the "entrypoint" as st_name:
+    Num:    Value          Size Type    Bind   Vis      Ndx Name
+    21: 0000000000001380  1264 FUNC    GLOBAL DEFAULT    1 entrypoint
+    30: 0000000000007b68  1392 FUNC    GLOBAL DEFAULT    1 entrypoint
+
+    - Second entry is the actual entrypoint
+    - First entry is a bad dynsym entry
+    - First entry would be PC 595
+    - This entry should not be registered in calldests
+    - So in a call to fd_sbpf_calldests_test( prog->calldests, 595 ), we should get 0
+  
+  * Entrypoint is not referenced in text section or relocation table
+    - Yet it must be in calldests, since we register it by default
+    - So in a call to fd_sbpf_calldests_test( prog->calldests, 3920 ), we should still get 1
+ 
+*/
+
+void test_duplicate_entrypoint_entry( void ) {
+  // TODO: boilerplate
+  fd_valloc_t valloc = fd_scratch_virtual();
+  fd_sbpf_elf_info_t info;
+
+  fd_sbpf_elf_peek( &info, duplicate_entrypoint_entry_elf, duplicate_entrypoint_entry_elf_sz );
+
+  void* rodata = fd_valloc_malloc( valloc, 8UL, info.rodata_footprint );
+  FD_TEST( rodata );
+
+
+
+  fd_sbpf_program_t * prog = fd_sbpf_program_new( fd_valloc_malloc( valloc, fd_sbpf_program_align(), fd_sbpf_program_footprint( &info ) ), &info, rodata );
+
+  fd_sbpf_syscalls_t * syscalls = fd_sbpf_syscalls_new( fd_valloc_malloc( valloc, fd_sbpf_syscalls_align(), fd_sbpf_syscalls_footprint() ));
+  for( uint const * x = _syscalls; *x; x++ )
+      fd_sbpf_syscalls_insert( syscalls, *x );
+
+  int res = fd_sbpf_program_load( prog, duplicate_entrypoint_entry_elf, duplicate_entrypoint_entry_elf_sz, syscalls );
+  FD_TEST( res == 0 );
+
+  // end of boilerplate
+
+  FD_TEST( fd_sbpf_calldests_test( prog->calldests, 595 ) == 0 ); 
+  FD_TEST( fd_sbpf_calldests_test( prog->calldests, 3920 ) == 1 );
+
+}
+
+int
+main(   int argc,
+        char ** argv ) {
+  fd_boot( &argc, &argv );
+
+  static uchar scratch_mem [ 1<<25 ];  /* 32MB */
+  static ulong scratch_fmem[ 4UL ] __attribute((aligned(FD_SCRATCH_FMEM_ALIGN)));
+  fd_scratch_attach( scratch_mem, scratch_fmem, 1UL<<25, 4UL );
+
+  // testing here
+  test_duplicate_entrypoint_entry();
+
+  fd_scratch_detach( NULL );
+  fd_halt();
+  return 0;
+}