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Refactor
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@rui314
rui314 committed Aug 3, 2022
1 parent 8f27689 commit ccf2cda
Showing 1 changed file with 53 additions and 49 deletions.
102 changes: 53 additions & 49 deletions macho/arch-arm64.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -469,25 +469,9 @@ void RangeExtensionThunk<E>::copy_buf(Context<E> &ctx) {
#define ASSERT_RANGE(val, start, size) \
assert((start) <= (val) && (val) < ((start) + (size)))

static void relax_adrp_ldr_got_ldr(Context<E> &ctx, ObjectFile<E> *file,
std::string_view &hints) {
i64 addr1 = read_uleb(hints);
i64 addr2 = read_uleb(hints);
i64 addr3 = read_uleb(hints);

Subsection<E> *subsec = file->find_subsection(ctx, addr1);
if (!subsec || !subsec->is_alive)
return;

ASSERT_RANGE(addr1, subsec->input_addr, subsec->input_size);
ASSERT_RANGE(addr2, subsec->input_addr, subsec->input_size);
ASSERT_RANGE(addr3, subsec->input_addr, subsec->input_size);

i64 offset1 = addr1 - subsec->input_addr;
i64 offset2 = addr2 - subsec->input_addr;
i64 offset3 = addr3 - subsec->input_addr;

u8 *loc = ctx.buf + subsec->isec.osec.hdr.offset + subsec->output_offset;
static void relax_adrp_ldr_got_ldr(Context<E> &ctx, Subsection<E> &subsec,
i64 offset1, i64 offset2, i64 offset3) {
u8 *loc = ctx.buf + subsec.isec.osec.hdr.offset + subsec.output_offset;
ul32 *loc1 = (ul32 *)(loc + offset1);
ul32 *loc2 = (ul32 *)(loc + offset2);
ul32 *loc3 = (ul32 *)(loc + offset3);
Expand All @@ -501,9 +485,9 @@ static void relax_adrp_ldr_got_ldr(Context<E> &ctx, ObjectFile<E> *file,
(*loc2 & 0xffc0'0000) != 0xf940'0000)
return;

u64 got_addr = page(subsec->get_addr(ctx) + offset1) +
(bits(*loc1, 23, 5) << 14) + (bits(*loc1, 30, 29) << 12) +
(bits(*loc2, 21, 10) << 3);
u64 got_addr = page(subsec.get_addr(ctx) + offset1) +
(bits(*loc1, 23, 5) << 14) + (bits(*loc1, 30, 29) << 12) +
(bits(*loc2, 21, 10) << 3);

ASSERT_RANGE(got_addr, ctx.got.hdr.addr, ctx.got.hdr.size);

Expand All @@ -516,7 +500,7 @@ static void relax_adrp_ldr_got_ldr(Context<E> &ctx, ObjectFile<E> *file,
switch (*loc3 & 0xffc0'0000) {
case 0xf940'0000: { // ldr Xc, [Xb, #imm]
u64 imm = bits(*loc3, 21, 10) * 8;
i64 disp = got_value + imm - subsec->get_addr(ctx) - offset3;
i64 disp = got_value + imm - subsec.get_addr(ctx) - offset3;
if (disp == sign_extend(disp, 20) && (disp & 0b11) == 0) {
*loc1 = 0xd503'201f; // nop
*loc2 = 0xd503'201f; // nop
Expand All @@ -527,7 +511,7 @@ static void relax_adrp_ldr_got_ldr(Context<E> &ctx, ObjectFile<E> *file,
}
case 0xb940'0000: { // ldr Wc, [Xb, #imm]
u64 imm = bits(*loc3, 21, 10) * 4;
i64 disp = got_value + imm - subsec->get_addr(ctx) - offset3;
i64 disp = got_value + imm - subsec.get_addr(ctx) - offset3;
if (disp == sign_extend(disp, 20) && (disp & 0b11) == 0) {
*loc1 = 0xd503'201f; // nop
*loc2 = 0xd503'201f; // nop
Expand All @@ -540,30 +524,17 @@ static void relax_adrp_ldr_got_ldr(Context<E> &ctx, ObjectFile<E> *file,
}

// If the GOT slot is close enough to PC, we can eliminate ADRP.
if (i64 disp = got_addr - subsec->get_addr(ctx) - offset2;
if (i64 disp = got_addr - subsec.get_addr(ctx) - offset2;
disp == sign_extend(disp, 20) && (disp & 0b11) == 0) {
*loc1 = 0xd503'201f; // nop
*loc2 = 0x5800'0000 | (bits(disp, 20, 2) << 5) |
bits(*loc2, 4, 0); // ldr Xb, _foo@GOT
}
}

static void relax_adrp_add(Context<E> &ctx, ObjectFile<E> *file,
std::string_view &hints) {
i64 addr1 = read_uleb(hints);
i64 addr2 = read_uleb(hints);

Subsection<E> *subsec = file->find_subsection(ctx, addr1);
if (!subsec || !subsec->is_alive)
return;

ASSERT_RANGE(addr1, subsec->input_addr, subsec->input_size);
ASSERT_RANGE(addr2, subsec->input_addr, subsec->input_size);

i64 offset1 = addr1 - subsec->input_addr;
i64 offset2 = addr2 - subsec->input_addr;

u8 *loc = ctx.buf + subsec->isec.osec.hdr.offset + subsec->output_offset;
static void relax_adrp_add(Context<E> &ctx, Subsection<E> &subsec,
i64 offset1, i64 offset2) {
u8 *loc = ctx.buf + subsec.isec.osec.hdr.offset + subsec.output_offset;
ul32 *loc1 = (ul32 *)(loc + offset1);
ul32 *loc2 = (ul32 *)(loc + offset2);

Expand All @@ -575,10 +546,10 @@ static void relax_adrp_add(Context<E> &ctx, ObjectFile<E> *file,
(*loc2 & 0xffc0'0000) != 0x9100'0000)
return;

u64 addr = page(subsec->get_addr(ctx) + offset1) +
(bits(*loc1, 23, 5) << 14) + (bits(*loc1, 30, 29) << 12) +
bits(*loc2, 21, 10);
i64 disp = addr - subsec->get_addr(ctx) - offset2;
u64 addr = page(subsec.get_addr(ctx) + offset1) +
(bits(*loc1, 23, 5) << 14) + (bits(*loc1, 30, 29) << 12) +
bits(*loc2, 21, 10);
i64 disp = addr - subsec.get_addr(ctx) - offset2;

if (disp == sign_extend(disp, 20)) {
*loc1 = 0xd503'201f; // nop
Expand Down Expand Up @@ -618,12 +589,45 @@ void apply_linker_optimization_hints(Context<E> &ctx) {
i64 nargs = read_uleb(hints);

switch (type) {
case LOH_ARM64_ADRP_LDR_GOT_LDR:
relax_adrp_ldr_got_ldr(ctx, file, hints);
case LOH_ARM64_ADRP_LDR_GOT_LDR: {
assert(nargs == 3);
i64 addr1 = read_uleb(hints);
i64 addr2 = read_uleb(hints);
i64 addr3 = read_uleb(hints);

Subsection<E> *subsec = file->find_subsection(ctx, addr1);
if (!subsec || !subsec->is_alive)
return;

ASSERT_RANGE(addr1, subsec->input_addr, subsec->input_size);
ASSERT_RANGE(addr2, subsec->input_addr, subsec->input_size);
ASSERT_RANGE(addr3, subsec->input_addr, subsec->input_size);

i64 offset1 = addr1 - subsec->input_addr;
i64 offset2 = addr2 - subsec->input_addr;
i64 offset3 = addr3 - subsec->input_addr;

relax_adrp_ldr_got_ldr(ctx, *subsec, offset1, offset2, offset3);
break;
case LOH_ARM64_ADRP_ADD:
relax_adrp_add(ctx, file, hints);
}
case LOH_ARM64_ADRP_ADD: {
assert(nargs == 2);
i64 addr1 = read_uleb(hints);
i64 addr2 = read_uleb(hints);

Subsection<E> *subsec = file->find_subsection(ctx, addr1);
if (!subsec || !subsec->is_alive)
return;

ASSERT_RANGE(addr1, subsec->input_addr, subsec->input_size);
ASSERT_RANGE(addr2, subsec->input_addr, subsec->input_size);

i64 offset1 = addr1 - subsec->input_addr;
i64 offset2 = addr2 - subsec->input_addr;

relax_adrp_add(ctx, *subsec, offset1, offset2);
break;
}
default:
// Skip unsupported optimizations hints.
for (i64 i = 0; i < nargs; i++)
Expand Down

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