Remove phase 1 IR

Phase 1 IR is previously served as a solution for bridging C frontend
to backend (elf code generation), which becomes obsolete after the
introduction of SSA middle-end. In this patch, "ph1_ir_t" and related
structures & functionalities are removed.

Notice that IR dumping is replace with "insn_t" with SSA-based control
flow, and several opcodes are removed as being only used in "ph1_ir_t".

Author: ChAoSUnItY

Makefile

@@ -4,6 +4,9 @@ CFLAGS := -O -g \
 	-fwrapv \
 	-Wall -Wextra \
 	-Wno-unused-but-set-variable \
+	-Wno-unused-parameter \
+	-Wno-unused-function \
+	-Wshadow \
 	-Wno-variadic-macros \
 	-Wno-uninitialized \
 	-Wno-strict-prototypes \

README.md

@@ -176,44 +176,39 @@ Execute the following to generate IR:
 $ out/shecc --dump-ir -o fib tests/fib.c
 ```
 
-Line-by-line explanation between C source and IR:
+Line-by-line explanation between C source and IR (variable and label numbering may differ):
 ```c
- C Source                IR                                         Explanation
-------------------+---------------------------------------+----------------------------------------------------------------------------------
-
-int fib(int n)      def int @fib(int %n)                    Indicate a function definition
-{                   {
-  if (n == 0)         const %.t1001, $0                     Load constant 0 into a temporary variable ".t1001"
-                      %.t1002 = eq %n, %.t1001              Test "n" equals ".t1001" or not, and write the result in temporary variable ".t1002"
-                      br %.t1002, .label.1177, .label.1178  If ".t1002" equals zero, goto false label ".label.1178", otherwise,
-                                                            goto true label ".label.1177"
-                    .label.1177
-    return 0;         const %.t1003, $0                     Load constant 0 into a temporary variable ".t1003"
-                      ret %.t1003                           Return ".t1003"
-                      j .label.1184                         Jump to endif label ".label.1184"
-                    .label.1178
-  else if (n == 1)    const %.t1004, $1                     Load constant 1 into a temporary variable ".t1004"
-                      %.t1005 = eq %n, %.t1004              Test "n" equals ".t1004" or not, and write the result in temporary variable ".t1005"
-                      br %.t1005, .label.1183, .label.1184  If ".t1005" equals zero, goto false label ".label.1184". Otherwise,
-                                                            goto true label ".label.1183"
-                    .label.1183
-    return 1;         const %.t1006, $1                     Load constant 1 into a temporary variable ".t1006"
-                      ret %.t1006                           Return ".t1006"
-                    .label.1184
-  return
-    fib(n - 1)        const %.t1007, $1                     Load constant 1 into a temporary variable ".t1007"
-                      %.t1008 = sub %n, %.t1007             Subtract ".t1007" from "n", and store the result in temporary variable ".t1008"
-                      push %.t1008                          Prepare parameter for function call
-                      call @fib, 1                          Call function "fib" with one parameter
-    +                 retval %.t1009                        Store return value in temporary variable ".t1009"
-    fib(n - 2);       const %.t1010, $2                     Load constant 2 into a temporary variable ".t1010"
-                      %.t1011 = sub %n, %.t1010             Subtract ".t1010" from "n", and store the result in temporary variable ".t1011"
-                      push %.t1011                          Prepare parameter for function call
-                      call @fib, 1                          Call function "fib" with one parameter
-                      retval %.t1012                        Store return value in temporary variable ".t1012"
-                      %.t1013 = add %.t1009, %.t1012        Add ".t1009" and ".t1012", and store the result in temporary variable ".t1013"
-                      ret %.t1013                           Return ".t1013"
-}                   }
+C Source                  IR                                         Explanation
+-------------------+--------------------------------------+--------------------------------------------------------------------------------------
+int fib(int n)       def int @fib(int %n)
+{                    {
+  if (n == 0)          const %.t871, 0                      Load constant 0 into a temporary variable ".t871"
+                       %.t872 = eq %n, %.t871               Test if "n" is equal to ".t871", store result in ".t872"
+                       br %.t872, .label.1430, .label.1431  If ".t872" is non-zero, branch to label ".label.1430", otherwise to ".label.1431"
+                     .label.1430:
+    return 0;          const %.t873, 0                      Load constant 0 into a temporary variable ".t873"
+                       ret %.t873                           Return ".t873"
+                     .label.1431:
+  else if (n == 1)     const %.t874, 1                      Load constant 1 into a temporary variable ".t874"
+                       %.t875 = eq %n, %.t874               Test if "n" is equal to ".t874", store result in ".t875"
+                       br %.t875, .label.1434, .label.1435  If ".t875" is true, branch to ".label.1434", otherwise to ".label.1435"
+                     .label.1434:
+    return 1;          const %.t876, 1                      Load constant 1 into a temporary variable ".t876"
+                       ret %.t876                           Return ".t876"
+                     .label.1435:
+  return fib(n - 1)    const %.t877, 1                      Load constant 1 into ".t877"
+                       %.t878 = sub %n, %.t877              Subtract ".t877" from "n", store in ".t878"
+                       push %.t878                          Prepare argument ".t878" for function call
+                       call @fib, 1                         Call function "@fib" with 1 argument
+         +             retval %.t879                        Store the return value in ".t879"
+         fib(n - 2);   const %.t880, 2                      Load constant 2 into ".t880"
+                       %.t881 = sub %n, %.t880              Subtract ".t880" from "n", store in ".t881"
+                       push %.t881                          Prepare argument ".t881" for function call
+                       call @fib, 1                         Call function "@fib" with 1 argument
+                       retval %.t882                        Store the return value in ".t882"
+                       %.t883 = add %.t879, %.t882          Add ".t879" and ".t882", store in ".t883"
+                       ret %.t883                           Return ".t883"
+}                    }
 ```
 
 ## Known Issues

src/defs.h

@@ -205,12 +205,9 @@ typedef enum {
     OP_load_data_address, /* lookup address of a constant in data section */
 
     /* control flow */
-    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 */
+    OP_branch,   /* conditional jump */
+    OP_jump,     /* unconditional jump */
+    OP_func_ret, /* returned value */
 
     /* function pointer */
     OP_address_of_func, /* resolve function entry */
@@ -338,17 +335,6 @@ typedef struct {
     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 dynamic array structure for sources in src/globals.c
@@ -469,8 +455,10 @@ struct basic_block {
     insn_list_t insn_list;
     ph2_ir_list_t ph2_ir_list;
     bb_connection_t prev[MAX_BB_PRED];
-    struct basic_block *next;  /* normal BB */
-    struct basic_block *then_; /* conditional BB */
+    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 *else_;
     struct basic_block *idom;
     struct basic_block *r_idom;