JIT Interface - Issues and testing approach

diff --git gdb/testsuite/gdb.base/jit-fake-code.c gdb/testsuite/gdb.base/jit-fake-code.c
new file mode 100644
index 0000000..c3c5183
--- /dev/null
+++ gdb/testsuite/gdb.base/jit-fake-code.c
@@ -0,0 +1,29 @@
+#include <stdio.h>
+
+/* BUILD: gcc -s -c jit-fake-code.c */
+
+void ** jit_code_fake(void) {
+    static void *addresses[7];
+    line_1:
+    printf("jit-fake: jit_code_fake line_1\n");
+    addresses[0] = &&line_1;
+    line_2:
+    printf("jit-fake: jit_code_fake line_2\n");
+    addresses[1] = &&line_2;
+    line_3:
+    printf("jit-fake: jit_code_fake line_3\n");
+    addresses[2] = &&line_3;
+    line_4:
+    printf("jit-fake: jit_code_fake line_4\n");
+    addresses[3] = &&line_4;
+    line_5:
+    printf("jit-fake: jit_code_fake line_5\n");
+    addresses[4] = &&line_5;
+    line_6:
+    printf("jit-fake: jit_code_fake line_6\n");
+    addresses[5] = &&line_6;
+    line_7:
+    printf("jit-fake: jit_code_fake line_7\n");
+    addresses[6] = &&line_7;
+    return addresses;
+}
\ No newline at end of file
diff --git gdb/testsuite/gdb.base/jit-fake-reader.c gdb/testsuite/gdb.base/jit-fake-reader.c
new file mode 100644
index 0000000..96f6626
--- /dev/null
+++ gdb/testsuite/gdb.base/jit-fake-reader.c
@@ -0,0 +1,105 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <gdb/jit-reader.h>
+
+#include "jit-fake.h"
+
+/*
+ * BUILD: gcc -g -fPIC -shared -o jit-fake-reader.so jit-fake-reader.c 
+ * 
+ * load in gdb: 
+ * jit-reader-load [YOUR SOURCE LOCATION]/gdb/testsuite/gdb.base/jit-fake-reader.so
+ */
+ 
+/* 
+ * Required for gdb License compliance, this code is MIT and therefore
+ * GPL compatible.
+ */
+GDB_DECLARE_GPL_COMPATIBLE_READER
+
+
+enum gdb_status jit_reader_read_debug_info(struct gdb_reader_funcs *self,
+                                       struct gdb_symbol_callbacks *cb,
+                                       void *memory, long memory_sz) {
+    struct gdb_object * obj;
+    struct gdb_symtab *symtab;
+    symbol_data_t * data;
+    
+    printf("jit-fake-reader: jit_reader_read_debug_info being called\n");
+    data = (symbol_data_t *)memory;
+    obj = cb->object_open(cb);
+    printf("jit-fake-reader: open symtab for %s\n", data->filename);
+    symtab = cb->symtab_open(cb, obj, data->filename);
+    {
+        void * start_address = data->line_addresses[0];
+        void * end_address = data->line_addresses[data->num_lines-1];
+        printf("jit-fake-reader: open block for %s %p->%p\n", 
+               data->func_name, 
+               start_address, 
+               end_address);
+        cb->block_open(cb, symtab, NULL, (unsigned long)start_address, 
+                       (unsigned long)end_address, data->func_name);
+    }
+    {
+        int i;
+        struct gdb_line_mapping *line_mappings;
+        line_mappings = (struct gdb_line_mapping *)calloc(
+                                       data->num_lines, 
+                                       sizeof(struct gdb_line_mapping));
+        for(i = 0; i < data->num_lines; i++) 
+        {        
+            line_mappings[i].line = data->line_offset + i;
+            line_mappings[i].pc = 
+                        (unsigned long)data->line_addresses[i];
+            printf("jit-fake-reader: line mapping %d = %p\n", 
+               line_mappings[i].line, 
+               (void *)line_mappings[i].pc);
+        }
+        cb->line_mapping_add(cb, symtab, data->num_lines, 
+                             line_mappings);
+        free(line_mappings);
+    }
+    printf("jit-fake-reader: closing symtab\n");
+    cb->symtab_close(cb, symtab);
+    printf("jit-fake-reader: closing object\n");
+    cb->object_close(cb, obj);
+    printf("jit-fake-reader: jit_reader_read_debug_info returning "
+           "GDB_SUCCESS\n");
+    return GDB_SUCCESS;
+}
+
+
+void jit_reader_destroy_reader(struct gdb_reader_funcs *self) {
+    printf("jit-fake-reader: jit_reader_destroy_reader being called\n");
+}
+
+struct gdb_frame_id jit_reader_get_frame_id(struct gdb_reader_funcs *self,
+                                        struct gdb_unwind_callbacks *c)
+{
+    static struct gdb_frame_id id;
+    printf("jit-fake-reader: jit_reader_get_frame_id being called\n");
+    id.code_address = 0;
+    id.stack_address = 0;
+    return id;
+}
+                                        
+
+enum gdb_status jit_reader_unwind_frame(struct gdb_reader_funcs *self,
+                                    struct gdb_unwind_callbacks *cb)
+{
+    printf("jit-fake-reader: jit_reader_unwind_frame being called\n");
+    return GDB_FAIL;
+}
+
+
+static struct gdb_reader_funcs jit_reader_funcs;
+
+
+struct gdb_reader_funcs *gdb_init_reader (void) {
+    jit_reader_funcs.reader_version = GDB_READER_INTERFACE_VERSION;
+    jit_reader_funcs.read = &jit_reader_read_debug_info;
+    jit_reader_funcs.unwind = &jit_reader_unwind_frame;
+    jit_reader_funcs.get_frame_id = &jit_reader_get_frame_id;
+    jit_reader_funcs.destroy = &jit_reader_destroy_reader;
+    return &jit_reader_funcs;
+}
\ No newline at end of file
diff --git gdb/testsuite/gdb.base/jit-fake.c gdb/testsuite/gdb.base/jit-fake.c
new file mode 100644
index 0000000..edae835
--- /dev/null
+++ gdb/testsuite/gdb.base/jit-fake.c
@@ -0,0 +1,98 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "jit-fake.h"
+
+/* BUILD: gcc -g jit-fake-code.o jit-fake.c -o jit-fake */
+/******************************************/
+/**** Start GDB JIT Hook Specific Bits ****/
+/******************************************/
+typedef enum
+{
+  JIT_NOACTION = 0,
+  JIT_REGISTER_FN,
+  JIT_UNREGISTER_FN
+} jit_actions_t;
+
+struct jit_code_entry
+{
+  struct jit_code_entry *next_entry;
+  struct jit_code_entry *prev_entry;
+  const char *symfile_addr;
+  uint64_t symfile_size;
+};
+
+struct jit_descriptor
+{
+  uint32_t version;
+  /* This type should be jit_actions_t, but we use uint32_t
+     to be explicit about the bitwidth.  */
+  uint32_t action_flag;
+  struct jit_code_entry *relevant_entry;
+  struct jit_code_entry *first_entry;
+};
+
+void __attribute__((noinline)) __jit_debug_register_code() { };
+
+struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
+/****************************************/
+/**** End GDB JIT Hook Specific Bits ****/
+/****************************************/
+
+
+void register_symbol_data(void *symfile_addr, size_t symfile_size) 
+{
+    struct jit_code_entry *entry = malloc(sizeof(struct jit_code_entry));
+    entry->symfile_addr = symfile_addr;
+    entry->symfile_size = symfile_size;
+    entry->prev_entry = NULL;
+    entry->next_entry = __jit_debug_descriptor.first_entry;
+    if(entry->next_entry != NULL) 
+    {
+        entry->next_entry->prev_entry = entry;
+    }
+    __jit_debug_descriptor.first_entry = entry;
+    __jit_debug_descriptor.relevant_entry = entry;
+    __jit_debug_descriptor.action_flag = JIT_REGISTER_FN;
+    __jit_debug_register_code();
+}
+
+
+symbol_data_t * create_symbol_data(char *filename, char *func_name, 
+                                   int line_offset, int num_lines, 
+                                   void ** line_addresses)
+{
+    symbol_data_t *symbol_data = malloc(sizeof(symbol_data_t));
+    strncpy(symbol_data->filename, filename, SYMBOL_DATA_MAX_STR_LEN);
+    strncpy(symbol_data->func_name, func_name, SYMBOL_DATA_MAX_STR_LEN);
+    symbol_data->line_offset = line_offset;
+    symbol_data->num_lines = num_lines;
+    memcpy(symbol_data->line_addresses, line_addresses, 
+           sizeof(void *) * num_lines);
+    return symbol_data;
+}
+
+
+void register_fake(char *filename, char *func_name, int line_offset, 
+                   int num_lines, void * line_addresses[])
+{
+    symbol_data_t *symbol_data = create_symbol_data(filename, func_name, 
+                                                    line_offset, 
+                                                    num_lines, 
+                                                    line_addresses);
+    
+    register_symbol_data(symbol_data, sizeof(symbol_data_t));
+}
+
+/* provided by jit-fake-code.so from jit-fake-code.c */
+void ** jit_code_fake(void);
+
+int main(int argc, char **argv) {
+    register_fake("fakefile.c", "fake_function", 1, 7, jit_code_fake());
+    jit_code_fake();
+    jit_code_fake();
+    jit_code_fake();
+    return 0;
+}
\ No newline at end of file
diff --git gdb/testsuite/gdb.base/jit-fake.h gdb/testsuite/gdb.base/jit-fake.h
new file mode 100644
index 0000000..5f37a42
--- /dev/null
+++ gdb/testsuite/gdb.base/jit-fake.h
@@ -0,0 +1,15 @@
+#ifndef JIT_FAKE_H
+#define JIT_FAKE_H
+
+#define SYMBOL_DATA_MAX_STR_LEN 2048
+#define SYMBOL_DATA_MAX_LINES 20
+
+typedef struct {
+    char filename[SYMBOL_DATA_MAX_STR_LEN];
+    char func_name[SYMBOL_DATA_MAX_STR_LEN];
+    int line_offset;
+    int num_lines;
+    void *line_addresses[SYMBOL_DATA_MAX_LINES];
+} symbol_data_t;
+
+#endif /* JIT_FAKE_H */
\ No newline at end of file