erts: Refactor line table in loaded beam code

to use real C struct with correct types

3 files changed, 54 insertions, 53 deletions

diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index c56e6732a0..1c598601c6 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -4388,9 +4388,11 @@ freeze_code(LoaderState* stp)
     if (stp->line_instr == 0) {
 	line_size = 0;
     } else {
-	line_size = (MI_LINE_FUNC_TAB + (stp->num_functions + 1) +
-		     (stp->current_li+1) + stp->num_fnames) *
-	    sizeof(Eterm) + (stp->current_li+1) * stp->loc_size;
+	line_size = (offsetof(BeamCodeLineTab,func_tab)
+                     + (stp->num_functions + 1) * sizeof(BeamInstr**) /* func_tab */
+                     + (stp->current_li + 1) * sizeof(BeamInstr*)     /* line items */
+                     + stp->num_fnames * sizeof(Eterm)                /* fname table */
+                     + (stp->current_li + 1) * stp->loc_size);        /* loc_tab */
     }
     size = offsetof(BeamCodeHeader,functions) + (stp->ci * sizeof(BeamInstr)) +
 	strtab_size + attr_size + compile_size + MD5_SIZE + line_size;
@@ -4465,42 +4467,40 @@ freeze_code(LoaderState* stp)
 	code_hdr->line_table = NULL;
 	str_table = (byte *) (codev + stp->ci);
     } else {
-	Eterm* line_tab = (Eterm *) (codev+stp->ci);
-	Eterm* p;
-	int ftab_size = stp->num_functions;
-	int num_instrs = stp->current_li;
-	Eterm* first_line_item;
+	BeamCodeLineTab* const line_tab = (BeamCodeLineTab *) (codev+stp->ci);
+	const int ftab_size = stp->num_functions;
+        const int num_instrs = stp->current_li;
+        const BeamInstr** const line_items =
+            (const BeamInstr**) &line_tab->func_tab[ftab_size + 1];
 
 	code_hdr->line_table = line_tab;
-	p = line_tab + MI_LINE_FUNC_TAB;
 
-	first_line_item = (p + ftab_size + 1);
 	for (i = 0; i < ftab_size; i++) {
-	     *p++ = (Eterm) (BeamInstr) (first_line_item + stp->func_line[i]);
+            line_tab->func_tab[i] = line_items + stp->func_line[i];
 	}
-	*p++ = (Eterm) (BeamInstr) (first_line_item + num_instrs);
-	ASSERT(p == first_line_item);
+	line_tab->func_tab[i] = line_items + num_instrs;
+
 	for (i = 0; i < num_instrs; i++) {
-		*p++ = (Eterm) (BeamInstr) (codev + stp->line_instr[i].pos);
+            line_items[i] = codev + stp->line_instr[i].pos;
 	}
-	*p++ = (Eterm) (BeamInstr) (codev + stp->ci - 1);
+	line_items[i] = codev + stp->ci - 1;
 
-	line_tab[MI_LINE_FNAME_PTR] = (Eterm) (BeamInstr) p;
-	memcpy(p, stp->fname, stp->num_fnames*sizeof(Eterm));
-	p += stp->num_fnames;
+	line_tab->fname_ptr = (Eterm*) &line_items[i + 1];
+	memcpy(line_tab->fname_ptr, stp->fname, stp->num_fnames*sizeof(Eterm));
 
-	line_tab[MI_LINE_LOC_TAB] = (Eterm) (BeamInstr) p;
-	line_tab[MI_LINE_LOC_SIZE] = stp->loc_size;
+	line_tab->loc_size = stp->loc_size;
 	if (stp->loc_size == 2) {
-	    Uint16* locp = (Uint16 *) p;
-	    for (i = 0; i < num_instrs; i++) {
+            Uint16* locp = (Uint16 *) &line_tab->fname_ptr[stp->num_fnames];
+            line_tab->loc_tab.p2 = locp;
+            for (i = 0; i < num_instrs; i++) {
 		*locp++ = (Uint16) stp->line_instr[i].loc;
-	    }
-	    *locp++ = LINE_INVALID_LOCATION;
+            }
+            *locp++ = LINE_INVALID_LOCATION;
             str_table = (byte *) locp;
 	} else {
-	    Uint32* locp = (Uint32 *) p;
-	    ASSERT(stp->loc_size == 4);
+	    Uint32* locp = (Uint32 *) &line_tab->fname_ptr[stp->num_fnames];
+            ASSERT(stp->loc_size == 4);
+            line_tab->loc_tab.p4 = locp;
 	    for (i = 0; i < num_instrs; i++) {
 		*locp++ = stp->line_instr[i].loc;
 	    }
diff --git a/erts/emulator/beam/beam_load.h b/erts/emulator/beam/beam_load.h
index c86ac65521..22ab71c868 100644
--- a/erts/emulator/beam/beam_load.h
+++ b/erts/emulator/beam/beam_load.h
@@ -61,6 +61,8 @@ extern BeamInstr* em_call_nif;
 /* Total code size in bytes */
 extern Uint erts_total_code_size;
 
+typedef struct BeamCodeLineTab_ BeamCodeLineTab;
+
 /*
  * Header of code chunks which contains additional information
  * about the loaded module.
@@ -100,7 +102,7 @@ typedef struct beam_code_header {
     /*
      * Pointer to the line table (or NULL if none).
      */
-    Eterm* line_table;
+    BeamCodeLineTab* line_table;
 
     /*
      * Pointer to the module MD5 sum (16 bytes)
@@ -124,11 +126,15 @@ int erts_is_module_native(BeamCodeHeader* code);
 /*
  * Layout of the line table.
  */
-
-#define MI_LINE_FNAME_PTR 0
-#define MI_LINE_LOC_TAB 1
-#define MI_LINE_LOC_SIZE 2
-#define MI_LINE_FUNC_TAB 3
+struct BeamCodeLineTab_ {
+    Eterm* fname_ptr;
+    int loc_size;
+    union {
+        Uint16* p2;
+        Uint32* p4;
+    }loc_tab;
+    const BeamInstr** func_tab[1];
+};
 
 #define LINE_INVALID_LOCATION (0)
 
diff --git a/erts/emulator/beam/beam_ranges.c b/erts/emulator/beam/beam_ranges.c
index e6cf43446e..5a2b66727a 100644
--- a/erts/emulator/beam/beam_ranges.c
+++ b/erts/emulator/beam/beam_ranges.c
@@ -37,7 +37,7 @@ typedef struct {
 #define RANGE_END(R) ((BeamInstr*)erts_smp_atomic_read_nob(&(R)->end))
 
 static Range* find_range(BeamInstr* pc);
-static void lookup_loc(FunctionInfo* fi, BeamInstr* pc,
+static void lookup_loc(FunctionInfo* fi, const BeamInstr* pc,
 		       BeamCodeHeader*, int idx);
 
 /*
@@ -296,39 +296,34 @@ find_range(BeamInstr* pc)
 }
 
 static void
-lookup_loc(FunctionInfo* fi, BeamInstr* orig_pc, BeamCodeHeader* code_hdr, int idx)
+lookup_loc(FunctionInfo* fi, const BeamInstr* pc,
+           BeamCodeHeader* code_hdr, int idx)
 {
-    Eterm* line = code_hdr->line_table;
-    Eterm* low;
-    Eterm* high;
-    Eterm* mid;
-    Eterm pc;
+    BeamCodeLineTab* lt = code_hdr->line_table;
+    const BeamInstr** low;
+    const BeamInstr** high;
+    const BeamInstr** mid;
 
-    if (line == 0) {
+    if (lt == NULL) {
 	return;
     }
 
-    pc = (Eterm) (BeamInstr) orig_pc;
-    fi->fname_ptr = (Eterm *) (BeamInstr) line[MI_LINE_FNAME_PTR];
-    low = (Eterm *) (BeamInstr) line[MI_LINE_FUNC_TAB+idx];
-    high = (Eterm *) (BeamInstr) line[MI_LINE_FUNC_TAB+idx+1];
+    fi->fname_ptr = lt->fname_ptr;
+    low = lt->func_tab[idx];
+    high = lt->func_tab[idx+1];
     while (high > low) {
 	mid = low + (high-low) / 2;
 	if (pc < mid[0]) {
 	    high = mid;
 	} else if (pc < mid[1]) {
 	    int file;
-	    int index = mid - (Eterm *) (BeamInstr) line[MI_LINE_FUNC_TAB];
+	    int index = mid - lt->func_tab[0];
 
-	    if (line[MI_LINE_LOC_SIZE] == 2) {
-		Uint16* loc_table =
-		    (Uint16 *) (BeamInstr) line[MI_LINE_LOC_TAB];
-		fi->loc = loc_table[index];
+	    if (lt->loc_size == 2) {
+		fi->loc = lt->loc_tab.p2[index];
 	    } else {
-		Uint32* loc_table =
-		    (Uint32 *) (BeamInstr) line[MI_LINE_LOC_TAB];
-		ASSERT(line[MI_LINE_LOC_SIZE] == 4);
-		fi->loc = loc_table[index];
+		ASSERT(lt->loc_size == 4);
+		fi->loc = lt->loc_tab.p4[index];
 	    }
 	    if (fi->loc == LINE_INVALID_LOCATION) {
 		return;