GCC source code Analysis, Expand_call () function and printf ("Hello, world!\n");

The Expand_call () function is in the expr.c file.

The following is the main debug result of the Expand_call () function, recorded.

The Debug_tree () function and the Debug_rtx () function are mainly added.

The Debug_tree () function joins the beginning of the expand_expr () function.

The Debug_rtx () function is added at the end of the Gen_rtx () function.

The Emit_call_1 () function is also visible when it is called. EMIT_CALL_INSN () is also visible when it is called.

The main purpose of debugging is how does the Expand_call () function generate RTX?

is both how to call the Gen_rtx () function and where to call it?

Of course only for the hello.c file:

printf ("Hello, world!\n");

This function is called to parse.

call_expr

Expand_call
expand_expr Code = 71
<nop_expr 830d8
Type <pointer_type 9017c
Type <integer_type 90130 char readonly permanent QI
Size &LT;INTEGER_CST 81638 literal permanent 1
Align 8 Size_unit 8 Sep_unit 8 Symtab 0
Sep <integer_cst 81608 literal permanent-128 precision 8 min <integer_cst 81608-128>
Max &LT;INTEGER_CST 81620 literal permanent 127
Pointer_to_this <pointer_type 9017c>
Permanent unsigned SI
Size &LT;INTEGER_CST 8154c literal permanent 4
Align Size_unit 8 sep_unit symtab 0
Chain <function_type 902c0>
Literal
Arg 0 <nop_expr 830c0
Type <pointer_type 87a44 type <integer_type 815BC char>
Permanent unsigned SI size &LT;INTEGER_CST 8154c 4>
Align Size_unit 8 sep_unit symtab 0
Chain <array_type 87a90>
Literal
Arg 0 <addr_expr 830a8 type <pointer_type 93f58>
Literal
Arg 0 <string_cst 83014 type <array_type 93ef4>
static literal "Hello, world!
"
expand_expr Code = 71
<nop_expr 830c0
Type <pointer_type 87a44
Type <integer_type 815BC Char permanent QI
Size &LT;INTEGER_CST 81638 literal permanent 1
Align 8 Size_unit 8 Sep_unit 8 Symtab 0
Sep <integer_cst 81608 literal permanent-128 precision 8 min <integer_cst 81608-128>
Max &LT;INTEGER_CST 81620 literal permanent 127
Pointer_to_this <pointer_type 87a44> chain <integer_type 816a8 Long int>
Permanent unsigned SI
Size &LT;INTEGER_CST 8154c literal permanent 4
Align Size_unit 8 sep_unit symtab 0
Chain <array_type 87a90>
Literal
Arg 0 <addr_expr 830a8
Type <pointer_type 93f58 type <array_type 93ef4>
unsigned SI size &LT;INTEGER_CST 8154c 4>
Align Size_unit 8 sep_unit symtab 0
Literal
Arg 0 <string_cst 83014 type <array_type 93ef4>
static literal "Hello, world!
"
expand_expr Code = 74
<addr_expr 830a8
Type <pointer_type 93f58
Type <array_type 93EF4 type <integer_type 815BC char>
BLK
Size &LT;INTEGER_CST 93f40 literal 15
Align 8 Size_unit 8 Sep_unit 8 Symtab 0
Sep <integer_cst 81638 literal permanent 1 domain <integer_type 93ea8>
Pointer_to_this <pointer_type 93f58> chain <pointer_type 93f58>
unsigned SI
Size &LT;INTEGER_CST 8154c literal permanent 4
Align Size_unit 8 sep_unit symtab 0
Literal
Arg 0 <string_cst 83014 type <array_type 93ef4>
static literal "Hello, world!
"
expand_expr Code = 26
&LT;STRING_CST 83014
Type <array_type 93EF4
Type <integer_type 815BC Char permanent QI
Size &LT;INTEGER_CST 81638 literal permanent 1
Align 8 Size_unit 8 Sep_unit 8 Symtab 0
Sep <integer_cst 81608 literal permanent-128 precision 8 min <integer_cst 81608-128>
Max &LT;INTEGER_CST 81620 literal permanent 127
Pointer_to_this <pointer_type 87a44> chain <integer_type 816a8 Long int>
BLK
Size &LT;INTEGER_CST 93f40 literal 15
Align 8 Size_unit 8 Sep_unit 8 symtab 0 Sep <integer_cst 81638 1>
Domain <integer_type 93ea8 SI
Size &LT;INTEGER_CST 8154c literal permanent 4
Align Size_unit 8 sep_unit symtab 0
Sep <integer_cst 83048 literal 0 precision min <integer_cst 83048 0>
Max &LT;INTEGER_CST 83078 literal 14
Pointer_to_this <pointer_type 93f58> chain <pointer_type 93f58>
static literal "Hello, world!
"
Output_constant_def

(Symbol_ref:si ("*lc0"))

(Mem:blk (Symbol_ref:si ("*lc0")))
This
addr_expr
Force_operand 27
End addr_expr

(Pre_dec:si (reg:si 7))

(Mem:si (Pre_dec:si (reg:si 7)))

(Set (Mem:si (Pre_dec:si (reg:si 7)))
(Symbol_ref:si ("*lc0")))

(Insn_list 6 (nil))

(Insn_list 2 (insn_list 6 (nil)))

(sequence[])

(Reg:si 0)

(Const_int 4)
Emit_call_1 Funexp Symbol_ref

(Mem:qi (Symbol_ref/v:si ("printf")))

(Call (Mem:qi (Symbol_ref/v:si ("printf")))
(Const_int 4))

(Set (Reg:si 0)
(Call (Mem:qi (Symbol_ref/v:si ("printf")))
(Const_int 4)))
Emit_call_insn
End Expand_call
C_expand_return

GCC source code Analysis, Expand_call () function and printf ("Hello, world!\n");