Integrate function-related structures

Since the introduction of SSA middle end, there exists 2 different
usage of function-related structures that is heavily coupled, but
used under different scenarios. This causes unnecessary confusions
to anyone who tries to understand it, and makes maintenance costly.

In this patch, "func_t" and "fn_t" are now integrated into "func_t",
and related variables are renamed into "func" instead of "fd" or "fn"
to keep naming consistency and avoid confusions to previous
structures.

Additionally, few comments are refined, and unused label definitions
removed to keep codebase tidy.

Author: ChAoSUnItY

src/arm-codegen.c

@@ -119,18 +119,13 @@ void update_elf_offset(ph2_ir_t *ph2_ir)
     case OP_return:
         elf_offset += 24;
         return;
-    case OP_trunc:
-        elf_offset += 4;
-        return;
-    case OP_sign_ext:
-        elf_offset += 4;
-        return;
     default:
-        fatal("Unknown opcode");
+        printf("Unknown opcode\n");
+        abort();
     }
 }
 
-void cfg_flatten(void)
+void cfg_flatten()
 {
     func_t *func = find_func("__syscall");
     func->bbs->elf_offset = 44; /* offset of start + exit in codegen */
@@ -184,7 +179,7 @@ void cfg_flatten(void)
 
 void emit(int code)
 {
-    elf_write_int(elf_code, code);
+    elf_write_code_int(code);
 }
 
 void emit_ph2_ir(ph2_ir_t *ph2_ir)
@@ -276,16 +271,16 @@ void emit_ph2_ir(ph2_ir_t *ph2_ir)
         emit(__teq(rn));
         if (ph2_ir->is_branch_detached) {
             emit(__b(__NE, 8));
-            emit(__b(__AL, ph2_ir->else_bb->elf_offset - elf_code->size));
+            emit(__b(__AL, ph2_ir->else_bb->elf_offset - elf_code_idx));
         } else
-            emit(__b(__NE, ph2_ir->then_bb->elf_offset - elf_code->size));
+            emit(__b(__NE, ph2_ir->then_bb->elf_offset - elf_code_idx));
         return;
     case OP_jump:
-        emit(__b(__AL, ph2_ir->next_bb->elf_offset - elf_code->size));
+        emit(__b(__AL, ph2_ir->next_bb->elf_offset - elf_code_idx));
         return;
     case OP_call:
         func = find_func(ph2_ir->func_name);
-        emit(__bl(__AL, func->bbs->elf_offset - elf_code->size));
+        emit(__bl(__AL, func->bbs->elf_offset - elf_code_idx));
         return;
     case OP_load_data_address:
         emit(__movw(__AL, rd, ph2_ir->src0 + elf_data_start));
@@ -426,28 +421,13 @@ void emit_ph2_ir(ph2_ir_t *ph2_ir)
         emit(__mov_i(__NE, rd, 0));
         emit(__mov_i(__EQ, rd, 1));
         return;
-    case OP_trunc:
-        if (rm == 1)
-            rm = 0xFF;
-        else if (rm == 2)
-            rm = 0xFFFF;
-        else if (rm == 4)
-            rm = 0xFFFFFFFF;
-        else
-            fatal("Unsupported truncation operation with invalid target size");
-
-        emit(__and_i(__AL, rd, rn, rm));
-        return;
-    case OP_sign_ext:
-        /* TODO: Allow to sign extends to other types */
-        emit(__sxtb(__AL, rd, rn, 0));
-        return;
     default:
-        fatal("Unknown opcode");
+        printf("Unknown opcode\n");
+        abort();
     }
 }
 
-void code_generate(void)
+void code_generate()
 {
     elf_data_start = elf_code_start + elf_offset;
 
@@ -456,7 +436,7 @@ void code_generate(void)
     emit(__movt(__AL, __r8, GLOBAL_FUNC->stack_size));
     emit(__sub_r(__AL, __sp, __sp, __r8));
     emit(__mov_r(__AL, __r12, __sp));
-    emit(__bl(__AL, GLOBAL_FUNC->bbs->elf_offset - elf_code->size));
+    emit(__bl(__AL, GLOBAL_FUNC->bbs->elf_offset - elf_code_idx));
 
     /* exit */
     emit(__movw(__AL, __r8, GLOBAL_FUNC->stack_size));
@@ -488,7 +468,7 @@ void code_generate(void)
     emit(__add_r(__AL, __r8, __r12, __r8));
     emit(__lw(__AL, __r0, __r8, 0));
     emit(__add_i(__AL, __r1, __r8, 4));
-    emit(__b(__AL, MAIN_BB->elf_offset - elf_code->size));
+    emit(__b(__AL, MAIN_BB->elf_offset - elf_code_idx));
 
     for (int i = 0; i < ph2_ir_idx; i++) {
         ph2_ir = PH2_IR_FLATTEN[i];

src/defs.h

@@ -205,9 +205,12 @@ typedef enum {
     OP_load_data_address, /* lookup address of a constant in data section */
 
     /* control flow */
-    OP_branch,   /* conditional jump */
-    OP_jump,     /* unconditional jump */
-    OP_func_ret, /* returned value */
+    OP_label,
+    OP_branch,      /* conditional jump */
+    OP_jump,        /* unconditional jump */
+    OP_func_ret,    /* returned value */
+    OP_block_start, /* code block start */
+    OP_block_end,   /* code block end */
 
     /* function pointer */
     OP_address_of_func, /* resolve function entry */
@@ -248,10 +251,6 @@ typedef enum {
     OP_bit_not,
     OP_negate,
 
-    /* data type conversion */
-    OP_trunc,
-    OP_sign_ext,
-
     /* entry point of the state machine */
     OP_start
 } opcode_t;
@@ -280,17 +279,8 @@ typedef struct use_chain_node {
     struct use_chain_node *prev;
 } use_chain_t;
 
-typedef struct var var_t;
-typedef struct type type_t;
-
-typedef struct var_list {
-    int capacity;
-    int size;
-    var_t **elements;
-} var_list_t;
-
 struct var {
-    type_t *type;
+    char type_name[MAX_TYPE_LEN];
     char var_name[MAX_VAR_LEN];
     int is_ptr;
     bool is_func;
@@ -315,6 +305,8 @@ struct var {
     bool is_const; /* whether a constant representaion or not */
 };
 
+typedef struct var var_t;
+
 typedef struct {
     char name[MAX_VAR_LEN];
     bool is_variadic;
@@ -330,17 +322,36 @@ typedef struct func func_t;
 
 /* block definition */
 struct block {
-    var_list_t locals;
+    var_t locals[MAX_LOCALS];
+    int next_local;
     struct block *parent;
     func_t *func;
     macro_t *macro;
+    int locals_size;
     struct block *next;
 };
 
 typedef struct block block_t;
+
+typedef struct {
+    block_t *head;
+    block_t *tail;
+} block_list_t;
+
+/* phase-1 IR definition */
+typedef struct {
+    opcode_t op;
+    char func_name[MAX_VAR_LEN];
+    int param_num;
+    int size;
+    var_t *dest;
+    var_t *src0;
+    var_t *src1;
+} ph1_ir_t;
+
 typedef struct basic_block basic_block_t;
 
-/* Definition of a growable buffer for a mutable null-terminated string
+/* Definition of a dynamic array structure for sources in src/globals.c
  * size:     Current number of elements in the array
  * capacity: Number of elements that can be stored without resizing
  * elements: Pointer to the array of characters
@@ -349,7 +360,7 @@ typedef struct {
     int size;
     int capacity;
     char *elements;
-} strbuf_t;
+} source_t;
 
 /* phase-2 IR definition */
 struct ph2_ir {
@@ -377,6 +388,8 @@ struct type {
     int num_fields;
 };
 
+typedef struct type type_t;
+
 /* lvalue details */
 typedef struct {
     int size;
@@ -456,10 +469,8 @@ struct basic_block {
     insn_list_t insn_list;
     ph2_ir_list_t ph2_ir_list;
     bb_connection_t prev[MAX_BB_PRED];
-    char bb_label_name[MAX_VAR_LEN]; /* Used in instruction dumping when ir_dump
-                                        is enabled. */
-    struct basic_block *next;        /* normal BB */
-    struct basic_block *then_;       /* conditional BB */
+    struct basic_block *next;  /* normal BB */
+    struct basic_block *then_; /* conditional BB */
     struct basic_block *else_;
     struct basic_block *idom;
     struct basic_block *r_idom;
@@ -536,48 +547,3 @@ typedef struct {
     var_t *var;
     int polluted;
 } regfile_t;
-
-/* FIXME: replace char[2] with a short data type in ELF header structures */
-/* ELF header */
-typedef struct {
-    char e_ident[16];
-    char e_type[2];
-    char e_machine[2];
-    int e_version;
-    int e_entry;
-    int e_phoff;
-    int e_shoff;
-    int e_flags;
-    char e_ehsize[2];
-    char e_phentsize[2];
-    char e_phnum[2];
-    char e_shentsize[2];
-    char e_shnum[2];
-    char e_shstrndx[2];
-} elf32_hdr_t;
-
-/* ELF program header */
-typedef struct {
-    int p_type;
-    int p_offset;
-    int p_vaddr;
-    int p_paddr;
-    int p_filesz;
-    int p_memsz;
-    int p_flags;
-    int p_align;
-} elf32_phdr_t;
-
-/* ELF section header */
-typedef struct {
-    int sh_name;
-    int sh_type;
-    int sh_flags;
-    int sh_addr;
-    int sh_offset;
-    int sh_size;
-    int sh_link;
-    int sh_info;
-    int sh_addralign;
-    int sh_entsize;
-} elf32_shdr_t;