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ir.c
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ir.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "wcc.h"
static List *allocated_tacs;
void init_ir(void) {
allocated_tacs = new_list(1024);
}
void free_ir(void) {
for (int i = 0; i < allocated_tacs->length; i++) wfree(allocated_tacs->elements[i]);
free_list(allocated_tacs);
}
// Allocate a new local variable or tempoary
static int new_local_index(Function *function) {
return -1 - function->local_symbol_count++;
}
void init_value(Value *v) {
v->preg = -1;
v->stack_index = 0;
v->ssa_subscript = -1;
v->live_range = -1;
}
void init_value_allocations(void) {
allocated_values = new_list(1024);
}
void free_values(void) {
for (int i = 0; i < allocated_values->length; i++) {
Value *v = allocated_values->elements[i];
wfree(v);
}
free_list(allocated_values);
}
Value *new_value(void) {
Value *v = wcalloc(1, sizeof(Value));
append_to_list(allocated_values, v);
init_value(v);
return v;
}
// Create a new typed integral constant value.
Value *new_integral_constant(int type_type, long value) {
Value *cv = new_value();
cv->int_value = value;
cv->type = new_type(type_type);
cv->is_constant = 1;
return cv;
}
// Create a new typed floating point constant value.
Value *new_floating_point_constant(int type_type, long double value) {
Value *cv = new_value();
cv->fp_value = value;
cv->type = new_type(type_type);
cv->is_constant = 1;
return cv;
}
// Duplicate a value
Value *dup_value(Value *src) {
Value *dst = new_value();
*dst = *src;
dst->type = dup_type(src->type);
return dst;
}
void add_tac_to_ir(Tac *tac) {
tac->next = 0;
if (!ir_start) {
ir_start = tac;
ir = tac;
}
else {
tac->prev = ir;
ir->next = tac;
ir = tac;
}
}
Tac *new_instruction(int operation) {
Tac *tac = wcalloc(1, sizeof(Tac));
append_to_list(allocated_tacs, tac);
tac->operation = operation;
return tac;
}
// Add instruction to the global intermediate representation ir
Tac *add_instruction(int operation, Value *dst, Value *src1, Value *src2) {
Tac *tac = new_instruction(operation);
tac->dst = dst;
tac->src1 = src1;
tac->src2 = src2;
add_tac_to_ir(tac);
return tac;
}
// Ensure the double linked list in an IR is correct by checking last pointers
void sanity_test_ir_linkage(Function *function) {
for (Tac *tac = function->ir; tac; tac = tac->next) {
if (tac->next && tac->next->prev != tac) {
printf("Linkage broken between:\n");
print_instruction(stdout, tac, 0);
print_instruction(stdout, tac->next, 0);
panic("Bailing");
}
}
}
int print_value(void *f, Value *v, int is_assignment_rhs) {
int c = 0; // Count outputted characters
if (!v) panic("print_value() got null");
if (v->is_lvalue) c += printf("{l}");
if (v->is_lvalue_in_register) c += printf("{lr}");
if (is_assignment_rhs && !v->is_lvalue && !v->vreg && !v->is_constant) c += fprintf(f, "&");
if (!is_assignment_rhs && v->is_lvalue && v->vreg) c += fprintf(f, "L");
if (v->is_constant) {
if (is_integer_type(v->type))
c += fprintf(f, "%ld", v->int_value);
else
c += fprintf(f, "%Lf", v->fp_value);
}
else if (v->preg != -1)
c += fprintf(f, "p%d", v->preg);
else if (v->local_index)
c += fprintf(f, "L[%d]", v->local_index);
else if (v->stack_index)
c += fprintf(f, "S[%d]", v->stack_index);
else if (v->vreg) {
c += fprintf(f, "r%d", v->vreg);
if (v->ssa_subscript != -1) c += fprintf(f, "_%d", v->ssa_subscript);
if (v->live_range_preg) c += fprintf(f, "_LRpreg%d", v->live_range_preg);
}
else if (v->stack_index)
c += fprintf(f, "s[%d]", v->stack_index);
else if (v->global_symbol)
c += fprintf(f, "%s", v->global_symbol->global_identifier);
else if (v->is_string_literal)
c += fprintf_escaped_string_literal(f, &(string_literals[v->string_literal_index]), 0);
else if (v->label)
c += fprintf(f, "l%d", v->label);
else if (v->function_symbol) {
c += fprintf(f, "function:%s", v->function_symbol->identifier);
return c;
}
else
// What's this?
c += fprintf(f, "?%ld", v->int_value);
if (v->bit_field_size) c += fprintf(f, "[bf %d:%d]", v->bit_field_offset, v->bit_field_size);
else if (v->offset) c += fprintf(f, "[%d]", v->offset);
if (!v->label) {
c += fprintf(f, ":");
c += print_type(f, v->type);
}
return c;
}
void print_instruction(void *f, Tac *tac, int expect_preg) {
int o = tac->operation;
if (tac->label)
fprintf(f, "l%-5d", tac->label);
else
fprintf(f, " ");
if (tac->x86_template) {
char *buffer = render_x86_operation(tac, 0, expect_preg);
fprintf(f, "%s\n", buffer);
wfree(buffer);
return;
}
if (tac->dst && o < X_START) {
print_value(f, tac->dst, o != IR_MOVE);
fprintf(f, " = ");
}
if (o == IR_MOVE_TO_PTR) {
fprintf(f, "(");
print_value(f, tac->src1, 0);
fprintf(f, ") = ");
}
if (o == IR_MOVE || o == IR_MOVE_PREG_CLASS || o == IR_LOAD_BIT_FIELD || o == IR_SAVE_BIT_FIELD)
print_value(f, tac->src1, 1);
else if (o == IR_LOAD_FROM_GOT) {
fprintf(f, "from GOT ");
print_value(f, tac->src1, 1);
}
else if (o == IR_MOVE_STACK_PTR)
fprintf(f, "rsp");
else if (o == IR_DECL_LOCAL_COMP_OBJ) {
fprintf(f, "declare ");
print_value(f, tac->src1, 1);
}
else if (o == IR_START_CALL) fprintf(f, "start call %ld", tac->src1->int_value);
else if (o == IR_END_CALL) fprintf(f, "end call %ld", tac->src1->int_value);
else if (o == IR_ARG || o == X_ARG) {
fprintf(f, "arg for call %ld ", tac->src1->int_value);
print_value(f, tac->src2, 1);
}
else if (o == IR_ARG_STACK_PADDING) {
fprintf(f, "arg extra push");
}
else if (o == IR_CALL) {
if (tac->src1->function_symbol)
fprintf(f, "call \"%s\"", tac->src1->function_symbol->identifier);
else {
fprintf(f, "call ");
print_value(f, tac->src1, 1);
}
}
else if (o == IR_VA_START) {
fprintf(f, "va_start ");
print_value(f, tac->src1, 1);
}
else if (o == IR_VA_ARG)
fprintf(f, "va_arg ");
else if (o == IR_ZERO) {
fprintf(f, "zero memory with size ");
print_value(f, tac->src1, 1);
}
else if (o == IR_LOAD_LONG_DOUBLE) {
fprintf(f, "load long double ");
print_value(f, tac->src1, 1);
}
else if (o == IR_RETURN) {
fprintf(f, "return");
if (tac->src1) {
fprintf(f, " ");
print_value(f, tac->src1, 1);
}
}
else if (o == IR_START_LOOP) fprintf(f, "start loop par=%ld loop=%ld", tac->src1->int_value, tac->src2->int_value);
else if (o == IR_END_LOOP) fprintf(f, "end loop par=%ld loop=%ld", tac->src1->int_value, tac->src2->int_value);
else if (o == IR_MOVE_TO_PTR)
print_value(f, tac->src2, 1);
else if (o == IR_NOP)
fprintf(f, "nop");
else if (o == IR_JZ || o == IR_JNZ) {
if (o == IR_JZ) fprintf(f, "jz ");
else if (o == IR_JNZ) fprintf(f, "jnz ");
print_value(f, tac->src1, 1);
fprintf(f, ", ");
print_value(f, tac->src2, 1);
}
else if (o == IR_JMP)
fprintf(f, "jmp l%d", tac->src1->label);
else if (o == IR_PHI_FUNCTION) {
fprintf(f, "Φ(");
Value *v = tac->phi_values;
int first = 1;
while (v->type) {
if (!first) fprintf(f, ", ");
print_value(f, v, 1);
first = 0;
v++;
}
fprintf(f, ")");
}
else if (o == IR_INDIRECT) { fprintf(f, "*"); print_value(f, tac->src1, 1); }
else if (o == IR_ADDRESS_OF) { fprintf(f, "&"); print_value(f, tac->src1, 1); }
else if (o == IR_ADDRESS_OF_FROM_GOT) { fprintf(f, "& from GOT"); print_value(f, tac->src1, 1); }
else if (o == IR_ADD) { print_value(f, tac->src1, 1); fprintf(f, " + "); print_value(f, tac->src2, 1); }
else if (o == IR_SUB) { print_value(f, tac->src1, 1); fprintf(f, " - "); print_value(f, tac->src2, 1); }
else if (o == IR_RSUB) { print_value(f, tac->src2, 1); fprintf(f, " - "); print_value(f, tac->src1, 1); fprintf(f, " [reverse]"); }
else if (o == IR_MUL) { print_value(f, tac->src1, 1); fprintf(f, " * "); print_value(f, tac->src2, 1); }
else if (o == IR_DIV) { print_value(f, tac->src1, 1); fprintf(f, " / "); print_value(f, tac->src2, 1); }
else if (o == IR_MOD) { print_value(f, tac->src1, 1); fprintf(f, " %% "); print_value(f, tac->src2, 1); }
else if (o == IR_BNOT) { fprintf(f, "~"); print_value(f, tac->src1, 1); }
else if (o == IR_EQ) { print_value(f, tac->src1, 1); fprintf(f, " == "); print_value(f, tac->src2, 1); }
else if (o == IR_NE) { print_value(f, tac->src1, 1); fprintf(f, " != "); print_value(f, tac->src2, 1); }
else if (o == IR_GT) { print_value(f, tac->src1, 1); fprintf(f, " > "); print_value(f, tac->src2, 1); }
else if (o == IR_LT) { print_value(f, tac->src1, 1); fprintf(f, " < "); print_value(f, tac->src2, 1); }
else if (o == IR_GE) { print_value(f, tac->src1, 1); fprintf(f, " >= "); print_value(f, tac->src2, 1); }
else if (o == IR_LE) { print_value(f, tac->src1, 1); fprintf(f, " <= "); print_value(f, tac->src2, 1); }
else if (o == IR_BAND) { print_value(f, tac->src1, 1); fprintf(f, " & "); print_value(f, tac->src2, 1); }
else if (o == IR_BOR) { print_value(f, tac->src1, 1); fprintf(f, " | "); print_value(f, tac->src2, 1); }
else if (o == IR_XOR) { print_value(f, tac->src1, 1); fprintf(f, " ^ "); print_value(f, tac->src2, 1); }
else if (o == IR_BSHL) { print_value(f, tac->src1, 1); fprintf(f, " << "); print_value(f, tac->src2, 1); }
else if (o == IR_BSHR) { print_value(f, tac->src1, 1); fprintf(f, " >> "); print_value(f, tac->src2, 1); }
else if (o == IR_ASHR) { print_value(f, tac->src1, 1); fprintf(f, " a>> "); print_value(f, tac->src2, 1); }
else if (o == X_CALL) { fprintf(f, "call " ); print_value(f, tac->src1, 1); if (tac->dst) { printf(" -> "); print_value(f, tac->dst, 1); } }
else if (o == IR_CALL_ARG_REG) { fprintf(f, "call reg arg "); print_value(f, tac->dst ? tac->dst : tac->src1 , 1); }
else if (o == IR_ALLOCATE_STACK){ fprintf(f, "allocate stack "); print_value(f, tac->src1, 1); }
else if (o == X_LEA) { fprintf(f, "lea " ); print_value(f, tac->src1, 1); fprintf(f, ", "); print_value(f, tac->dst, 1); }
else if (o == X_MOV) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); fprintf(f, ", "); print_value(f, tac->dst, 1); }
else if (o == X_MOVS) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); fprintf(f, ", "); print_value(f, tac->dst, 1); }
else if (o == X_MOVZ) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); fprintf(f, ", "); print_value(f, tac->dst, 1); }
else if (o == X_MOVC) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); fprintf(f, ", "); print_value(f, tac->dst, 1); }
else if (o == X_ADD) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); fprintf(f, ", "); print_value(f, tac->dst, 1); }
else if (o == X_MUL) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); fprintf(f, ", "); print_value(f, tac->dst, 1); }
else if (o == X_IDIV) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); fprintf(f, ", "); print_value(f, tac->dst, 1); }
else if (o == X_CQTO) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); fprintf(f, ", "); print_value(f, tac->dst, 1); }
else if (o == X_CMP) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); fprintf(f, ", "); print_value(f, tac->src2, 1); }
else if (o == X_CMPZ) { fprintf(f, "%-6s", operation_string(o)); fprintf(f, "0"); fprintf(f, ", "); print_value(f, tac->src1, 1); }
else if (o == X_JMP) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JZ) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JNZ) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JE) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JNE) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JLT) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JGT) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JLE) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JGE) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JB) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JA) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JBE) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_JAE) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_SETE) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_SETNE) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_SETLT) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_SETGT) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_SETLE) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else if (o == X_SETGE) { fprintf(f, "%-6s", operation_string(o)); print_value(f, tac->src1, 1); }
else
panic("print_instruction(): Unknown operation: %d", tac->operation);
fprintf(f, "\n");
}
void print_ir(Function *function, char* name, int expect_preg) {
if (name) fprintf(stdout, "%s:\n", name);
int i = 0;
for (Tac *tac = function->ir; tac; tac = tac->next) {
fprintf(stdout, "%-4d > ", i++);
print_instruction(stdout, tac, expect_preg);
}
fprintf(stdout, "\n");
}
// Merge tac with the instruction after it. The next instruction is removed from the chain.
static void merge_instructions(Tac *tac, int ir_index, int allow_labelled_next) {
if (!tac->next) panic("merge_instructions called on a tac without next\n");
if (tac->next->label && !allow_labelled_next) panic("merge_instructions called on a tac with a label");
Tac *next = tac->next;
tac->next = next->next;
if (tac->next) tac->next->prev = tac;
// Nuke the references to the removed node to prevent confusion
next->prev = 0;
next->next = 0;
}
int make_function_call_count(Function *function) {
// Need to count this IR's function_call_count
int function_call_count = 0;
for (Tac *tac = function->ir; tac; tac = tac->next)
if (tac->operation == IR_START_CALL) function_call_count++;
return function_call_count;
}
// The arguments are pushed onto the stack right to left, but the ABI requries
// the seventh arg and later to be pushed in reverse order. Easiest is to flip
// all args backwards, so they are pushed left to right.
void reverse_function_argument_order(Function *function) {
const int MAX_ARGS = 256;
typedef struct tac_interval {
Tac *start;
Tac *end;
} TacInterval;
// Need to count this IR's function_call_count
int function_call_count = make_function_call_count(function);
// First index, function_id, second index arg_id
TacInterval *function_args;
function_args = wmalloc(sizeof(TacInterval) * function_call_count * MAX_ARGS);
int *arg_counts = wcalloc(function_call_count, sizeof(int));
Tac **calls = wcalloc(function_call_count, sizeof(Tac *));
Tac **call_starts = wcalloc(function_call_count, sizeof(Tac *));
ir = function->ir;
// Collect function call details in one pass through the IR
Tac *tac = function->ir;
while (tac) {
if (tac->operation == IR_START_CALL) {
int func = tac->src1->int_value;
TacInterval *args = &(function_args[func * MAX_ARGS]);
call_starts[func] = tac;
tac = tac->next;
args[arg_counts[func]].start = tac;
}
else if (tac->operation == IR_END_CALL) {
int func = tac->src1->int_value;
calls[func] = tac->prev;
tac = tac->next;
}
else if (tac->operation == IR_ARG) {
int func = tac->src1->int_value;
TacInterval *args = &(function_args[func * MAX_ARGS]);
args[arg_counts[func]].end = tac;
tac = tac->next;
if (tac->operation == IR_ARG_STACK_PADDING) {
args[arg_counts[func]].end = tac;
tac = tac->next;
}
arg_counts[func]++;
if (tac->operation != IR_END_CALL) args[arg_counts[func]].start = tac;
}
else
tac = tac->next;
}
// Reverse the args for each function call
for (int i = 0; i < function_call_count; i++) {
TacInterval *args = &(function_args[i * MAX_ARGS]);
int arg_count = arg_counts[i];
Tac *call = calls[i];
Tac *call_start = call_starts[i];
if (arg_count > 1) {
call_start->next = args[arg_count - 1].start;
args[arg_count - 1].start->prev = call_start;
args[0].end->next = call;
call->prev = args[0].end;
for (int j = 0; j < arg_count; j++) {
// Rearrange args backwards from this IR
// cs -> p0.start -> p0.end -> p1.start -> p1.end -> cs.end
// cs -> p0.start -> p0.end -> p1.start -> p1.end -> p2.start -> p2.end -> cs.end
if (j < arg_count - 1) {
args[j + 1].end->next = args[j].start;
args[j].start->prev = args[j + 1].end;
}
}
}
}
wfree(function_args);
wfree(arg_counts);
wfree(calls);
wfree(call_starts);
}
// Insert tac instruction before ir
void insert_instruction(Tac *ir, Tac *tac, int move_label) {
Tac *prev = ir->prev;
if (!ir->prev) panic("insert_instruction called with null prev");
tac->origin = ir->origin;
tac->prev = prev;
tac->next = ir;
ir->prev = tac;
prev->next = tac;
if (move_label) {
tac->label = ir->label;
ir->label = 0;
}
}
Tac *insert_instruction_from_operation(Tac *ir, int operation, Value *dst, Value *src1, Value *src2, int move_label) {
Tac *tac = new_instruction(operation);
tac->dst = dst;
tac->src1 = src1;
tac->src2 = src2;
insert_instruction(ir, tac, move_label);
return tac;
}
// Append tac to ir
Tac *insert_instruction_after(Tac *ir, Tac *tac) {
tac->origin = ir->origin;
Tac *next = ir->next;
ir->next = tac;
tac->prev = ir;
tac->next = next;
if (next) next->prev = tac;
return tac;
}
Tac *insert_instruction_after_from_operation(Tac *ir, int operation, Value *dst, Value *src1, Value *src2) {
Tac *tac = new_instruction(operation);
tac->dst = dst;
tac->src1 = src1;
tac->src2 = src2;
Tac *next = ir->next;
ir->next = tac;
tac->prev = ir;
tac->next = next;
if (next) next->prev = tac;
return tac;
}
// Delete an instruction inside a linked list. It cannot be the first instruction.
Tac *delete_instruction(Tac *tac) {
if (!tac->prev) panic("Attempt to delete the first instruction");
if (tac->next && tac->next->label) panic("Deleting an instruction would obliterate the next label");
tac->prev->next = tac->next;
if (tac->next) tac->next->prev = tac->prev;
tac->next->label = tac->label;
return tac->next;
}
// Renumber all labels so they are consecutive. Uses label_count global.
void renumber_labels(Function *function) {
// Find highest label number in the function
int max_label_count = 0;
for (Tac *tac = function->ir; tac; tac = tac->next) {
if (tac->src1 && tac->src1->label && tac->src1->label > max_label_count) max_label_count = tac->src1->label;
if (tac->src2 && tac->src2->label && tac->src2->label > max_label_count) max_label_count = tac->src2->label;
if (tac->label && tac->label > max_label_count) max_label_count = tac->label;
}
if (!max_label_count) return;
int *mapping = wcalloc(max_label_count + 1, sizeof(int));
// Make mapping of old to new label indexes
for (Tac *tac = function->ir; tac; tac = tac->next) {
if (tac->src1 && tac->src1->label && !mapping[tac->src1->label]) mapping[tac->src1->label] = ++label_count;
if (tac->src2 && tac->src2->label && !mapping[tac->src2->label]) mapping[tac->src2->label] = ++label_count;
if (tac->label && !mapping[tac->label]) mapping[tac->label] = ++label_count;
}
// Set int_value to one for renamed labels. This is needed since some Value objects
// are shared, and should not be renamed twice.
for (Tac *tac = function->ir; tac; tac = tac->next) {
if (tac->src1 && tac->src1->label && !tac->src1->int_value) { tac->src1->label = mapping[tac->src1->label]; tac->src1->int_value = 1; }
if (tac->src2 && tac->src2->label && !tac->src2->int_value) { tac->src2->label = mapping[tac->src2->label]; tac->src2->int_value = 1; }
if (tac->label) tac->label = mapping[tac->label];
}
for (Tac *tac = function->ir; tac; tac = tac->next) {
if (tac->src1 && tac->src1->label) tac->src1->int_value = 0;
if (tac->src2 && tac->src2->label) tac->src2->int_value = 0;
}
wfree(mapping);
}
#define renumber_value(v) { \
if (v && v->label) { \
int replacement = (long) longmap_get(renumbers, v->label); \
if (replacement) v->label = replacement; \
} \
}
// When the parser completes, each jmp target is a nop with its own label. This can lead
// to consecutive nops with different labels. Merge those nops and labels into one.
// Gather all renumbers in one pass and apply them in a second pass.
void merge_consecutive_labels(Function *function) {
LongMap *renumbers = new_longmap();
int i = 0;
for (Tac *tac = function->ir; tac; tac = tac->next) {
while(1) {
if (!tac->label || !tac->next || !tac->next->label) break;
Tac *deleted_tac = tac->next;
merge_instructions(tac, i, 1);
int src = deleted_tac->label;
int dst = tac->label;
int renumbered_src = (long) longmap_get(renumbers, src); if (renumbered_src) src = renumbered_src;
int renumbered_dst = (long) longmap_get(renumbers, dst); if (renumbered_dst) dst = renumbered_dst;
longmap_put(renumbers, src, (void *) (long) dst);
}
i++;
}
for (Tac *tac = function->ir; tac; tac = tac->next) {
renumber_value(tac->dst);
renumber_value(tac->src1);
renumber_value(tac->src2);
}
free_longmap(renumbers);
}
static void assign_local_to_register(Value *v, int vreg) {
v->local_index = 0;
v->is_lvalue = 0;
v->vreg = vreg;
}
// Set on_stack to one if the value is a long double, struct/union or array
static void set_on_stack(Value *v, char *on_stack) {
int type = v->type->type;
if (type == TYPE_LONG_DOUBLE || type == TYPE_STRUCT_OR_UNION || type == TYPE_ARRAY)
on_stack[-v->local_index] = 1;
}
// The parser allocates a local_index for temporaries and local variables. Allocate
// vregs for them unless any of them is used with an & operator, or are long doubles, in
// which case, they must be on the stack.
// Function parameters aren't touched in this function
void allocate_value_vregs(Function *function) {
char *on_stack = wcalloc(function->local_symbol_count + 1, sizeof(char));
for (Tac *tac = function->ir; tac; tac = tac->next) {
// Keep variables that are used with the & operator on the stack
if (tac->operation == IR_ADDRESS_OF && tac->src1->local_index < 0) on_stack[-tac->src1->local_index] = 1;
// Keep long doubles, struct/unions and arrays on the stack
if (tac->dst && tac->dst ->type && tac->dst ->local_index < 0) set_on_stack(tac->dst, on_stack);
if (tac->src1 && tac->src1->type && tac->src1->local_index < 0) set_on_stack(tac->src1, on_stack);
if (tac->src2 && tac->src2->type && tac->src2->local_index < 0) set_on_stack(tac->src2, on_stack);
}
for (int i = 1; i <= function->local_symbol_count; i++) {
if (on_stack[i]) continue;
int vreg = ++function->vreg_count;
for (Tac *tac = function->ir; tac; tac = tac->next) {
if (tac->dst && tac->dst ->local_index == -i) assign_local_to_register(tac->dst , vreg);
if (tac->src1 && tac->src1->local_index == -i) assign_local_to_register(tac->src1, vreg);
if (tac->src2 && tac->src2->local_index == -i) assign_local_to_register(tac->src2, vreg);
}
}
wfree(on_stack);
}
// IR_JZ and IR_JNZ aren't implemented in the backend for SSE & long doubles.
// Convert:
// - IR_JZ => IR_EQ with 0.0 & IR_JNZ
// - IR_JNZ => IR_NE with 0.0 & IR_JNZ
void convert_long_doubles_jz_and_jnz(Function *function) {
make_vreg_count(function, 0);
for (Tac *ir = function->ir; ir; ir = ir->next) {
if ((ir->operation == IR_JZ || ir->operation == IR_JNZ) && is_floating_point_type(ir->src1->type)) {
ir->operation = ir->operation == IR_JZ ? IR_EQ : IR_NE;
Tac *tac = new_instruction(IR_JNZ);
tac->operation = IR_JNZ;
ir->dst = new_value();
ir->dst->type = new_type(TYPE_INT);
ir->dst->vreg = ++function->vreg_count;
tac->src1 = ir->dst;
tac->src2 = ir->src2;
ir->src2 = new_floating_point_constant(ir->src1->type->type, 0.0L);
ir = insert_instruction_after(ir, tac);
}
}
}
// Long double rvalues never live in registers, ensure all of them are on the stack
void move_long_doubles_to_the_stack(Function *function) {
make_vreg_count(function, 0);
int *local_indexes = wcalloc(function->vreg_count + 1, sizeof(int));
for (Tac *tac = function->ir; tac; tac = tac->next) {
// Long doubles in vregs are moved to the stack
if (tac->dst && tac->dst ->vreg && tac->dst ->type && tac->dst ->type->type == TYPE_LONG_DOUBLE && !tac->dst ->is_lvalue && !local_indexes[tac->dst ->vreg])
local_indexes[tac->dst ->vreg] = new_local_index(function);
if (tac->src1 && tac->src1->vreg && tac->src1->type && tac->src1->type->type == TYPE_LONG_DOUBLE && !tac->src1->is_lvalue && !local_indexes[tac->src1->vreg])
local_indexes[tac->src1->vreg] = new_local_index(function);
if (tac->src2 && tac->src2->vreg && tac->src2->type && tac->src2->type->type == TYPE_LONG_DOUBLE && !tac->src2->is_lvalue && !local_indexes[tac->src2->vreg])
local_indexes[tac->src2->vreg] = new_local_index(function);
}
for (Tac *tac = function->ir; tac; tac = tac->next) {
if (tac-> dst && tac-> dst->vreg && local_indexes[tac-> dst->vreg]) { tac-> dst->local_index = local_indexes[tac-> dst->vreg]; tac-> dst->vreg = 0; }
if (tac->src1 && tac->src1->vreg && local_indexes[tac->src1->vreg]) { tac->src1->local_index = local_indexes[tac->src1->vreg]; tac->src1->vreg = 0; }
if (tac->src2 && tac->src2->vreg && local_indexes[tac->src2->vreg]) { tac->src2->local_index = local_indexes[tac->src2->vreg]; tac->src2->vreg = 0; }
}
wfree(local_indexes);
}
void make_stack_register_count(Function *function) {
int min = 0;
for (Tac *tac = function->ir; tac; tac = tac->next) {
// Map registers forced onto the stack due to use of &
if (tac-> dst && tac-> dst->stack_index < 0 && tac-> dst->stack_index < min) min = tac-> dst->stack_index;
if (tac->src1 && tac->src1->stack_index < 0 && tac->src1->stack_index < min) min = tac->src1->stack_index;
if (tac->src2 && tac->src2->stack_index < 0 && tac->src2->stack_index < min) min = tac->src2->stack_index;
}
function->stack_register_count = -min;
}
// allocate a stack_index values:
// - without a vreg,
// - used in a & expression,
// - are long double
//
// Pushed variables by the caller have local_index >= 2 and are mapped through.
void allocate_value_stack_indexes(Function *function) {
int stack_register_count = 0;
int *stack_index_map = wmalloc((function->local_symbol_count + 1) * sizeof(int));
memset(stack_index_map, -1, (function->local_symbol_count + 1) * sizeof(int));
if (debug_ssa_mapping_local_stack_indexes) print_ir(function, 0, 0);
// Make stack_index_map
for (Tac *tac = function->ir; tac; tac = tac->next) {
// Map registers forced onto the stack
if (tac->dst && tac->dst->local_index < 0 && stack_index_map[-tac->dst->local_index] == -1)
stack_index_map[-tac->dst->local_index] = stack_register_count++;
if (tac->src1 && tac->src1->local_index < 0 && stack_index_map[-tac->src1->local_index] == -1)
stack_index_map[-tac->src1->local_index] = stack_register_count++;
if (tac->src2 && tac->src2->local_index < 0 && stack_index_map[-tac->src2->local_index] == -1)
stack_index_map[-tac->src2->local_index] = stack_register_count++;
}
for (Tac *tac = function->ir; tac; tac = tac->next) {
// Map registers forced onto the stack
if (tac->dst && tac->dst->local_index < 0)
tac->dst->stack_index = -stack_index_map[-tac->dst->local_index] - 1;
if (tac->src1 && tac->src1->local_index < 0)
tac->src1->stack_index = -stack_index_map[-tac->src1->local_index] - 1;
if (tac->src2 && tac->src2->local_index < 0)
tac->src2->stack_index = -stack_index_map[-tac->src2->local_index] - 1;
// Map function call parameters
if (tac->dst && tac->dst ->local_index > 0) tac->dst ->stack_index = tac->dst ->local_index;
if (tac->src1 && tac->src1->local_index > 0) tac->src1->stack_index = tac->src1->local_index;
if (tac->src2 && tac->src2->local_index > 0) tac->src2->stack_index = tac->src2->local_index;
}
// From this point onwards, local_index has no meaning and downstream code must not use it.
for (Tac *tac = function->ir; tac; tac = tac->next) {
if (tac->dst ) tac->dst ->local_index = 0;
if (tac->src1) tac->src1->local_index = 0;
if (tac->src2) tac->src2->local_index = 0;
}
function->stack_register_count = stack_register_count;
if (debug_ssa_mapping_local_stack_indexes)
printf("Moved %d registers to stack\n", stack_register_count);
if (debug_ssa_mapping_local_stack_indexes) print_ir(function, 0, 0);
wfree(stack_index_map);
}
// If a function returns a value and it's called, the parser will always allocate a
// vreg for the result. This function removes the vreg if it's not used anywhere further
// on.
void remove_unused_function_call_results(Function *function) {
int vreg_count = 0;
for (Tac *tac = function->ir; tac; tac = tac->next) {
if (tac->dst && tac->dst ->vreg && tac->dst ->vreg > vreg_count) vreg_count = tac->dst ->vreg;
if (tac->src1 && tac->src1->vreg && tac->src1->vreg > vreg_count) vreg_count = tac->src1->vreg;
if (tac->src2 && tac->src2->vreg && tac->src2->vreg > vreg_count) vreg_count = tac->src2->vreg;
}
char *used_vregs = wcalloc(vreg_count + 1, sizeof(char));
Tac *tac = function->ir;
while (tac->next) tac = tac->next;
while (tac) {
if (tac->src1 && tac->src1->vreg) used_vregs[tac->src1->vreg] = 1;
if (tac->src2 && tac->src2->vreg) used_vregs[tac->src2->vreg] = 1;
if (tac->operation == IR_MOVE && tac->dst->vreg && tac->dst->is_lvalue) used_vregs[tac->dst->vreg] = 1;
if (tac->operation == IR_CALL && tac->dst && tac->dst->vreg && !used_vregs[tac->dst->vreg]) tac->dst = 0;
tac = tac->prev;
}
wfree(used_vregs);
}
static Value *insert_address_of_instruction_after(Function *function, Tac **ir, Value *src) {
Value *v = new_value();
v->vreg = ++function->vreg_count;
v->type = make_pointer_to_void();
*ir = insert_instruction_after_from_operation(*ir, IR_ADDRESS_OF, v, src, 0);
return v;
}
static Tac *insert_arg_instruction_after(Tac *ir, Value *function_call_value, Value *v, int int_arg_index) {
Value *arg_value = dup_value(function_call_value);
arg_value->function_call_arg_index = int_arg_index;
FunctionParamAllocation *fpa = init_function_param_allocaton(NULL);
FunctionParamLocations *fpl = wmalloc(sizeof(FunctionParamLocations));
append_to_list(fpa->param_locations, fpl);
arg_value->function_call_arg_locations = fpl;
fpl->locations = wmalloc(sizeof(FunctionParamLocation));
memset(fpl->locations, -1, sizeof(FunctionParamLocation));
fpl->count = 1;
fpl->locations[0].int_register = int_arg_index;
fpl->locations[0].sse_register = -1;
return insert_instruction_after_from_operation(ir, IR_ARG, 0, arg_value, v);
}
static Tac *insert_function_call_instructions_after(Tac *ir, Value *call_value, Symbol *symbol) {
// Add call instruction
Value *function_value = new_value();
function_value->int_value = call_value->int_value;
function_value->function_symbol = symbol;
function_value->type = symbol->type;
function_value->function_call_arg_push_count = 0;
function_value->function_call_sse_register_arg_count = 0;
call_value->function_call_arg_push_count = 0;
call_value->function_call_arg_stack_padding = 0;
ir = insert_instruction_after_from_operation(ir, IR_CALL, 0, function_value, 0);
// Add end call instruction
ir = insert_instruction_after_from_operation(ir, IR_END_CALL, 0, call_value, 0);
}
// Add memcpy calls for struct/union -> struct/union copies
Tac *add_memory_copy_with_memcpy(Function *function, Tac *ir, Value *dst, Value *src1, int size) {
int function_call_count = make_function_call_count(function);
// Add start call instruction
Value *call_value = make_function_call_value(function_call_count++);
ir = insert_instruction_after_from_operation(ir, IR_START_CALL, 0, call_value, 0);
// Load of addresses of src1, dst & make size value
Value *src1_value;
if (src1->is_lvalue && src1->vreg)
src1_value = src1;
else
src1_value = insert_address_of_instruction_after(function, &ir, src1);
Value *dst_value;
if (dst->is_lvalue && dst->vreg)
dst_value = dst;
else
dst_value = insert_address_of_instruction_after(function, &ir, dst);
Value *size_value = new_integral_constant(TYPE_LONG, size);
// Add arg instructions
ir = insert_arg_instruction_after(ir, call_value, dst_value, 0);
ir = insert_arg_instruction_after(ir, call_value, src1_value, 1);
ir = insert_arg_instruction_after(ir, call_value, size_value, 2);
// Add function call
ir = insert_function_call_instructions_after(ir, call_value, memcpy_symbol);
return ir;
}
// Copy struct/unions using registers
//
// splay_offsets is used when copying a struct with SSE values from the vararg register
// save area. The SSE registers are saved with an annoying offset of 16 instead of 8.
Tac *add_memory_copy_with_registers(Function *function, Tac *ir, Value *dst, Value *src1, int size, int splay_offsets) {
int dst_offset = dst->offset;
int src1_offset = src1->offset;
// Do moves of size 8, 4, 2, 1 in order until there are no moves left
for (int i = 3; i >= 0; i -= 1) {
int step = 1 << i;
while (size >= step) {
Value *temp_value = new_value();
temp_value->type = new_type(TYPE_CHAR + i);
temp_value->vreg = ++function->vreg_count;
Value *offsetted_dst = dup_value(dst);
offsetted_dst->offset = dst_offset;
offsetted_dst->type = temp_value->type;
Value *offsetted_src1 = dup_value(src1);
int splayed_offset = (splay_offsets && src1_offset >= 8) ? src1_offset + 8 : src1_offset;
offsetted_src1->offset = splayed_offset;
offsetted_src1->type = temp_value->type;
if (src1->is_lvalue && src1->vreg) {
// Make it a pointer and add an indirect instruction
Value *indirect_src1 = dup_value(offsetted_src1);
indirect_src1->type = make_pointer(temp_value->type);
indirect_src1->is_lvalue = 0;
ir = insert_instruction_after_from_operation(ir, IR_INDIRECT, temp_value, indirect_src1, 0);
} else
ir = insert_instruction_after_from_operation(ir, IR_MOVE, temp_value, offsetted_src1, 0);
ir = insert_instruction_after_from_operation(ir, IR_MOVE, offsetted_dst, temp_value, 0);
size -= step;
dst_offset += step;
src1_offset += step;
}
}
return ir;
}
Tac *add_memory_copy(Function *function, Tac *ir, Value *dst, Value *src1, int size) {
// If either src or dst is an lvalue in a register, or the struct size > 32,
// use a memory copy. Otherwise use temporary registers to do the copy.
if (size > 32)
ir = add_memory_copy_with_memcpy(function, ir, dst, src1, size);
else
ir = add_memory_copy_with_registers(function, ir, dst, src1, size, 0);
return ir;
}
// Add memcpy calls for struct/union -> struct/union copies
void process_struct_and_union_copies(Function *function) {
for (Tac *ir = function->ir; ir; ir = ir->next) {
if (ir->operation != IR_MOVE) continue;
if (ir->src1->type->type != TYPE_STRUCT_OR_UNION) continue;
if (ir->dst->type->type != ir->src1->type->type) panic("Mismatched struct/union copy type");
int size = get_type_size(ir->dst->type);
Value *dst = ir->dst;
Value *src1 = ir->src1;
ir->operation = IR_NOP;
ir->dst = 0;
ir->src1 = 0;
add_memory_copy(function, ir, dst, src1, size);
}
}
// Determine offset (in bytes), which has integer alignment.
// Within the alignment, determine the offset (in bits) and size (in bits)
void determine_bit_field_params(Value *v, int *offset, int *bit_offset, int *bit_size) {
*offset = v->offset & (~3); // Align to the nearest integer boundary
*bit_offset = v->bit_field_offset - (*offset << 3);
*bit_size = v->bit_field_size;
}
// Load a bit field by loading the entire integer from a struct and bit shifting
static void add_load_bit_field(Function *function, Tac *ir) {
int offset, bit_offset, bit_size;
determine_bit_field_params(ir->src1, &offset, &bit_offset, &bit_size);
Value *src1 = dup_value(ir->src1);
src1->offset = offset;
src1->bit_field_offset = 0;
src1->bit_field_size = 0;
Value *dst = ir->dst;
Value *loaded_value = dup_value(ir->dst);
loaded_value->vreg = ++function->vreg_count;
ir->operation = IR_NOP;
ir->dst = 0;
ir->src1 = 0;
ir->src2 = 0;
if (src1->is_lvalue && src1->vreg) {
// Make it a pointer and add an indirect instruction