Merge branch 'sverk/better-module-info'

OTP-11940

* sverk/better-module-info:
  Remove obsolete 'imports' entry from module_info/1/2 functions
  Add 'module' entry for module_info/0 function for completeness
  Add 'md5' entry for module_info/0/1 functions.

5 files changed, 77 insertions, 17 deletions

diff --git a/erts/emulator/beam/atom.names b/erts/emulator/beam/atom.names
index d28e519ae1..dc930f2d38 100644
--- a/erts/emulator/beam/atom.names
+++ b/erts/emulator/beam/atom.names
@@ -278,7 +278,6 @@ atom http httph https http_response http_request http_header http_eoh http_error
 atom id
 atom if_clause
 atom ignore
-atom imports
 atom in
 atom in_exiting
 atom inactive
@@ -333,6 +332,7 @@ atom max
 atom maximum
 atom max_tables max_processes
 atom mbuf_size
+atom md5
 atom memory
 atom memory_internal
 atom memory_types
diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index e96177cfd9..a4e72a130a 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -245,7 +245,7 @@ typedef struct {
 /*
  * This structure contains all information about the module being loaded.
  */  
-
+#define MD5_SIZE 16
 typedef struct LoaderState {
     /*
      * The current logical file within the binary.
@@ -292,7 +292,7 @@ typedef struct LoaderState {
     StringPatch* string_patches; /* Linked list of position into string table to patch. */
     BeamInstr catches;		/* Linked list of catch_yf instructions. */
     unsigned loaded_size;	/* Final size of code when loaded. */
-    byte mod_md5[16];		/* MD5 for module code. */
+    byte mod_md5[MD5_SIZE];	/* MD5 for module code. */
     int may_load_nif;           /* true if NIFs may later be loaded for this module */  
     int on_load;		/* Index in the code for the on_load function
 				 * (or 0 if there is no on_load function)
@@ -528,6 +528,7 @@ static Eterm exported_from_module(Process* p, Eterm mod);
 static Eterm functions_in_module(Process* p, Eterm mod);
 static Eterm attributes_for_module(Process* p, Eterm mod);
 static Eterm compilation_info_for_module(Process* p, Eterm mod);
+static Eterm md5_of_module(Process* p, Eterm mod);
 static Eterm native_addresses(Process* p, Eterm mod);
 int patch_funentries(Eterm Patchlist);
 int patch(Eterm Addresses, Uint fe);
@@ -648,6 +649,7 @@ erts_prepare_loading(Binary* magic, Process *c_p, Eterm group_leader,
     stp->code[MI_COMPILE_PTR] = 0;
     stp->code[MI_COMPILE_SIZE] = 0;
     stp->code[MI_COMPILE_SIZE_ON_HEAP] = 0;
+    stp->code[MI_MD5_PTR] = 0;
 
     /*
      * Read the atom table.
@@ -4038,7 +4040,7 @@ freeze_code(LoaderState* stp)
     }
     size = (stp->ci * sizeof(BeamInstr)) +
 	(stp->total_literal_size * sizeof(Eterm)) +
-	strtab_size + attr_size + compile_size + line_size;
+	strtab_size + attr_size + compile_size + MD5_SIZE + line_size;
 
     /*
      * Move the code to its final location.
@@ -4247,11 +4249,20 @@ freeze_code(LoaderState* stp)
 	code[MI_COMPILE_SIZE_ON_HEAP] = decoded_size;
     }
     CHKBLK(ERTS_ALC_T_CODE,code);
+    {
+	byte* md5_sum = str_table + strtab_size + attr_size + compile_size;
+	CHKBLK(ERTS_ALC_T_CODE,code);
+	sys_memcpy(md5_sum, stp->mod_md5, MD5_SIZE);
+	CHKBLK(ERTS_ALC_T_CODE,code);
+	code[MI_MD5_PTR] = (BeamInstr) md5_sum;
+	CHKBLK(ERTS_ALC_T_CODE,code);
+    }
+    CHKBLK(ERTS_ALC_T_CODE,code);
 
     /*
      * Make sure that we have not overflowed the allocated code space.
      */
-    ASSERT(str_table + strtab_size + attr_size + compile_size ==
+    ASSERT(str_table + strtab_size + attr_size + compile_size + MD5_SIZE ==
 	   ((byte *) code) + size);
 
     /*
@@ -5103,10 +5114,11 @@ erts_module_info_0(Process* p, Eterm module)
     hp += 3; \
     list = CONS(hp, tup, list)
 
+    BUILD_INFO(am_md5);
     BUILD_INFO(am_compile);
     BUILD_INFO(am_attributes);
-    BUILD_INFO(am_imports);
     BUILD_INFO(am_exports);
+    BUILD_INFO(am_module);
 #undef BUILD_INFO
     return list;
 }
@@ -5116,8 +5128,8 @@ erts_module_info_1(Process* p, Eterm module, Eterm what)
 {
     if (what == am_module) {
 	return module;
-    } else if (what == am_imports) {
-	return NIL;
+    } else if (what == am_md5) {
+	return md5_of_module(p, module);
     } else if (what == am_exports) {
 	return exported_from_module(p, module);
     } else if (what == am_functions) {
@@ -5306,7 +5318,7 @@ attributes_for_module(Process* p, /* Process whose heap to use. */
     Eterm result = NIL;
     Eterm* end;
 
-    if (is_not_atom(mod) || (is_not_list(result) && is_not_nil(result))) {
+    if (is_not_atom(mod)) {
 	return THE_NON_VALUE;
     }
 
@@ -5345,7 +5357,7 @@ compilation_info_for_module(Process* p, /* Process whose heap to use. */
     Eterm result = NIL;
     Eterm* end;
 
-    if (is_not_atom(mod) || (is_not_list(result) && is_not_nil(result))) {
+    if (is_not_atom(mod)) {
 	return THE_NON_VALUE;
     }
 
@@ -5368,6 +5380,33 @@ compilation_info_for_module(Process* p, /* Process whose heap to use. */
 }
 
 /*
+ * Returns the MD5 checksum for a module
+ *
+ * Returns a tagged term, or 0 on error.
+ */
+
+Eterm
+md5_of_module(Process* p, /* Process whose heap to use. */
+              Eterm mod) /* Tagged atom for module. */
+{
+    Module* modp;
+    BeamInstr* code;
+    Eterm res = NIL;
+
+    if (is_not_atom(mod)) {
+	return THE_NON_VALUE;
+    }
+
+    modp = erts_get_module(mod, erts_active_code_ix());
+    if (modp == NULL) {
+	return THE_NON_VALUE;
+    }
+    code = modp->curr.code;
+    res = new_binary(p, (byte *) code[MI_MD5_PTR], MD5_SIZE);
+    return res;
+}
+
+/*
  * Build a single {M,F,A,Loction} item to be part of
  * a stack trace.
  */
@@ -5543,7 +5582,7 @@ code_module_md5_1(BIF_ALIST_1)
 	res = am_undefined;
 	goto done;
     }
-    res = new_binary(p, stp->mod_md5, sizeof(stp->mod_md5));
+    res = new_binary(p, stp->mod_md5, MD5_SIZE);
 
  done:
     erts_free_aligned_binary_bytes(temp_alloc);
@@ -5939,6 +5978,7 @@ erts_make_stub_module(Process* p, Eterm Mod, Eterm Beam, Eterm Info)
     code[MI_LITERALS_END] = 0;
     code[MI_LITERALS_OFF_HEAP] = 0;
     code[MI_ON_LOAD_FUNCTION_PTR] = 0;
+    code[MI_MD5_PTR] = 0;
     ci = MI_FUNCTIONS + n + 1;
 
     /*
diff --git a/erts/emulator/beam/beam_load.h b/erts/emulator/beam/beam_load.h
index bd22b0c4de..0e3ca0bdb0 100644
--- a/erts/emulator/beam/beam_load.h
+++ b/erts/emulator/beam/beam_load.h
@@ -91,7 +91,6 @@ extern Uint erts_total_code_size;
 #define MI_LITERALS_END		8
 #define MI_LITERALS_OFF_HEAP	9
 
-
 /*
  * Pointer to the on_load function (or NULL if none).
  */
@@ -103,6 +102,11 @@ extern Uint erts_total_code_size;
 #define MI_LINE_TABLE 11
 
 /*
+ * Pointer to the module MD5 sum (16 bytes)
+ */
+#define MI_MD5_PTR 12
+
+/*
  * Start of function pointer table.  This table contains pointers to
  * all functions in the module plus an additional pointer just beyond
  * the end of the last function.
@@ -111,7 +115,7 @@ extern Uint erts_total_code_size;
  * this table.
  */
 
-#define MI_FUNCTIONS         12
+#define MI_FUNCTIONS         13
 
 /*
  * Layout of the line table.
diff --git a/erts/emulator/test/module_info_SUITE.erl b/erts/emulator/test/module_info_SUITE.erl
index 8a63d9fe3e..f3986f0c4f 100644
--- a/erts/emulator/test/module_info_SUITE.erl
+++ b/erts/emulator/test/module_info_SUITE.erl
@@ -24,7 +24,7 @@
 -export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1, 
 	 init_per_group/2,end_per_group/2,
 	 init_per_testcase/2,end_per_testcase/2,
-	 exports/1,functions/1,native/1]).
+	 exports/1,functions/1,native/1,info/1]).
 
 %%-compile(native).
 
@@ -52,8 +52,8 @@ end_per_group(_GroupName, Config) ->
     Config.
 
 
-modules() -> 
-    [exports, functions, native].
+modules() ->
+    [exports, functions, native, info].
 
 init_per_testcase(Func, Config) when is_atom(Func), is_list(Config) ->
     Dog = ?t:timetrap(?t:minutes(3)),
@@ -122,6 +122,22 @@ native_proj({Name,Arity,Addr}) ->
 native_filter(Set) ->
     sofs:no_elements(Set) =/= 1.
 
+%% Test that the module info of this module is correct. Use
+%% erlang:get_module_info(?MODULE) to avoid compiler optimization tricks.
+info(Config) when is_list(Config) ->
+    Info = erlang:get_module_info(?MODULE),
+    All = all_exported(),
+    {ok,{?MODULE,MD5}} = beam_lib:md5(code:which(?MODULE)),
+    {module, ?MODULE} = lists:keyfind(module, 1, Info),
+    {md5, MD5} = lists:keyfind(md5, 1, Info),
+    {exports, Exports} = lists:keyfind(exports, 1, Info),
+    All = lists:sort(Exports),
+    {attributes, Attrs} = lists:keyfind(attributes, 1, Info),
+    {vsn,_} = lists:keyfind(vsn, 1, Attrs),
+    {compile, Compile} = lists:keyfind(compile, 1, Info),
+    {options,_} = lists:keyfind(options, 1, Compile),
+    ok.
+
 %% Helper functions (local).
 
 add_arity(L) ->
diff --git a/erts/preloaded/src/erlang.erl b/erts/preloaded/src/erlang.erl
index 1508eed9ee..dd3ea87c90 100644
--- a/erts/preloaded/src/erlang.erl
+++ b/erts/preloaded/src/erlang.erl
@@ -1664,7 +1664,7 @@ element(_N, _Tuple) ->
 %% Not documented
 -spec erlang:get_module_info(Module, Item) -> ModuleInfo when
       Module :: atom(),
-      Item :: module | imports | exports | functions | attributes | compile | native_addresses,
+      Item :: module | imports | exports | functions | attributes | compile | native_addresses | md5,
       ModuleInfo :: atom() | [] | [{atom(), arity()}] | [{atom(), term()}] | [{atom(), arity(), integer()}].
 get_module_info(_Module, _Item) ->
     erlang:nif_error(undefined).