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WASM_X64: Support Data Segment #1585

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Merged
merged 8 commits into from
Mar 24, 2023
Merged

WASM_X64: Support Data Segment #1585

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7a6849e
X86Assembler: Fix elf comment
ubaidsk Mar 23, 2023
da04529
WASM_X64: Support text and data segments
ubaidsk Mar 23, 2023
cd769ef
X86Assembler: Update add_var() and add_var64() to use labels
ubaidsk Mar 23, 2023
7e48c49
WASM_X64: Align segments by alignment byte
ubaidsk Mar 23, 2023
aa6c67f
WASM_X64: Remove use of add_var_size()
ubaidsk Mar 23, 2023
ba1da0f
X86Assembler: Remove unused parameter
ubaidsk Mar 23, 2023
7357202
X86Assembler: Use align macro for assembly text format
ubaidsk Mar 24, 2023
1b62e6b
CTEST: Update reference test for x86 asm
ubaidsk Mar 24, 2023
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18 changes: 13 additions & 5 deletions src/libasr/codegen/wasm_to_x64.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -579,7 +579,7 @@ class X64Visitor : public WASMDecoder<X64Visitor>,
void visit_F32Sqrt() { visit_F64Sqrt(); }

void gen_x64_bytes() {
emit_elf64_header(m_a, 7U);
emit_elf64_header(m_a);

// declare compile-time strings
std::string base_memory = " "; /* in wasm backend, memory starts after 4 bytes*/
Expand All @@ -589,6 +589,9 @@ class X64Visitor : public WASMDecoder<X64Visitor>,
label_to_str["base_memory"] = base_memory;

NO_OF_IMPORTS = imports.size();

m_a.align_by_byte(0x1000);
m_a.add_label("text_segment_start");
for (uint32_t idx = 0; idx < type_indices.size(); idx++) {
m_a.add_label(exports[idx + 1].name);
{
Expand All @@ -607,14 +610,18 @@ class X64Visitor : public WASMDecoder<X64Visitor>,

}

for (auto &s : label_to_str) {
emit_data_string(m_a, s.first, s.second);
}

for (auto &d : double_consts) {
emit_double_const(m_a, d.first, d.second);
}

m_a.add_label("text_segment_end");

m_a.align_by_byte(0x1000);
m_a.add_label("data_segment_start");
for (auto &s : label_to_str) {
emit_data_string(m_a, s.first, s.second);
}

for (size_t i = 0; i < globals.size(); i++) {
uint32_t tmp_offset = globals[i].insts_start_idx;
wasm::read_b8(wasm_bytes, tmp_offset); // read byte for i32/i64/f32/f64.const
Expand Down Expand Up @@ -644,6 +651,7 @@ class X64Visitor : public WASMDecoder<X64Visitor>,
default: throw CodeGenError("decode_global_section: Unsupport global type"); break;
}
}
m_a.add_label("data_segment_end");

emit_elf64_footer(m_a);
}
Expand Down
60 changes: 43 additions & 17 deletions src/libasr/codegen/x86_assembler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,6 @@ void emit_elf32_header(X86Assembler &a, uint32_t p_flags) {
a.asm_dw_imm16(0); // e_shnum
a.asm_dw_imm16(0); // e_shstrndx

a.add_var("ehdrsize", a.pos()-a.get_defined_symbol("ehdr").value);

/* Elf32_Phdr */
a.add_label("phdr");
Expand All @@ -74,13 +73,16 @@ void emit_elf32_header(X86Assembler &a, uint32_t p_flags) {
a.asm_dd_label("filesize"); // p_memsz
a.asm_dd_imm32(p_flags); // p_flags
a.asm_dd_imm32(0x1000); // p_align
a.add_label("phdr_end");

a.add_var("phdrsize", a.pos()-a.get_defined_symbol("phdr").value);
a.add_var("e_phoff", a.get_defined_symbol("phdr").value-a.origin());
a.add_var("ehdrsize", "ehdr", "phdr");
a.add_var("phdrsize", "phdr", "phdr_end");
a.add_var("e_phoff", "ehdr", "phdr");
}

void emit_elf32_footer(X86Assembler &a) {
a.add_var_size("filesize");
a.add_label("footer");
a.add_var("filesize", "ehdr", "footer");
}

void emit_exit(X86Assembler &a, const std::string &name,
Expand Down Expand Up @@ -281,8 +283,8 @@ void emit_print_float(X86Assembler &a, const std::string &name) {

/************************* 64-bit functions **************************/

void emit_elf64_header(X86Assembler &a, uint32_t p_flags) {
/* Elf32_Ehdr */
void emit_elf64_header(X86Assembler &a) {
/* Elf64_Ehdr */
a.add_label("ehdr");
// e_ident
a.asm_db_imm8(0x7F);
Expand Down Expand Up @@ -313,30 +315,54 @@ void emit_elf64_header(X86Assembler &a, uint32_t p_flags) {
a.asm_dd_imm32(0); // e_flags
a.asm_dw_label("ehdrsize"); // e_ehsize
a.asm_dw_label("phdrsize"); // e_phentsize
a.asm_dw_imm16(1); // e_phnum
a.asm_dw_imm16(3); // e_phnum
a.asm_dw_imm16(0); // e_shentsize
a.asm_dw_imm16(0); // e_shnum
a.asm_dw_imm16(0); // e_shstrndx

a.add_var("ehdrsize", a.pos()-a.get_defined_symbol("ehdr").value);

/* Elf32_Phdr */
/* Elf64_Phdr */
a.add_label("phdr");
a.asm_dd_imm32(1); // p_type
a.asm_dd_imm32(p_flags); // p_flags
a.asm_dd_imm32(1); // p_type
a.asm_dd_imm32(4); // p_flags (permission to read only)
a.asm_dq_imm64(0); // p_offset
a.asm_dq_imm64(a.origin()); // p_vaddr
a.asm_dq_imm64(a.origin()); // p_paddr
a.asm_dq_label("filesize"); // p_filesz
a.asm_dq_label("filesize"); // p_memsz
a.asm_dq_label("phdr_size"); // p_filesz
a.asm_dq_label("phdr_size"); // p_memsz
a.asm_dq_imm64(0x1000); // p_align

a.add_var("phdrsize", a.pos()-a.get_defined_symbol("phdr").value);
a.add_var64("e_phoff", a.get_defined_symbol("phdr").value-a.origin());
/* text_segment_phdr */
a.add_label("text_phdr");
a.asm_dd_imm32(1); // p_type
a.asm_dd_imm32(5); // p_flags (permission to read and execute)
a.asm_dq_label("text_segment_offset"); // p_offset
a.asm_dq_label("text_segment_start"); // p_vaddr
a.asm_dq_label("text_segment_start"); // p_paddr
a.asm_dq_label("text_segment_size"); // p_filesz
a.asm_dq_label("text_segment_size"); // p_memsz
a.asm_dq_imm64(0x1000); // p_align

/* data_segment_phdr */
a.add_label("data_phdr");
a.asm_dd_imm32(1); // p_type
a.asm_dd_imm32(6); // p_flags (permission to read and write)
a.asm_dq_label("data_segment_offset"); // p_offset
a.asm_dq_label("data_segment_start"); // p_vaddr
a.asm_dq_label("data_segment_start"); // p_paddr
a.asm_dq_label("data_segment_size"); // p_filesz
a.asm_dq_label("data_segment_size"); // p_memsz
a.asm_dq_imm64(0x1000); // p_align
}

void emit_elf64_footer(X86Assembler &a) {
a.add_var_size("filesize");
a.add_var("ehdrsize", "ehdr", "phdr");
a.add_var("phdrsize", "phdr", "text_phdr");
a.add_var64("e_phoff", "ehdr", "phdr");
a.add_var64("phdr_size", "ehdr", "text_segment_start");
a.add_var64("text_segment_offset", "ehdr", "text_segment_start");
a.add_var64("text_segment_size", "text_segment_start", "text_segment_end");
a.add_var64("data_segment_offset", "ehdr", "data_segment_start");
a.add_var64("data_segment_size", "data_segment_start", "data_segment_end");
}

void emit_exit_64(X86Assembler &a, std::string name, int exit_code) {
Expand Down
33 changes: 18 additions & 15 deletions src/libasr/codegen/x86_assembler.h
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,7 @@ Old Link: https://www.systutorials.com/go/intel-x86-64-reference-manual/
#include <sstream>
#include <fstream>
#include <map>
#include <cmath>

#include <libasr/alloc.h>
#include <libasr/containers.h>
Expand All @@ -40,13 +41,11 @@ Old Link: https://www.systutorials.com/go/intel-x86-64-reference-manual/
#ifdef LFORTRAN_ASM_PRINT
# define EMIT(s) emit(" ", s)
# define EMIT_LABEL(s) emit("", s)
# define EMIT_VAR(a, b) emit("\n", a + " equ " + i2s(b) + "\n")
# define EMIT_VAR_SIZE(a) emit("\n", a + " equ $ - $$\n") // $ is current addr, $$ is start addr
# define EMIT_VAR(a, b, c) emit(" ", a + " equ " + c + " - " + b)
#else
# define EMIT(s)
# define EMIT_LABEL(s)
# define EMIT_VAR(a, b)
# define EMIT_VAR_SIZE(a)
#endif

namespace LCompilers {
Expand Down Expand Up @@ -465,6 +464,15 @@ class X86Assembler {
return m_code;
}

void align_by_byte(uint64_t alignment) {
uint64_t code_size = m_code.size() ;
uint64_t padding_size = (alignment * ceil(code_size / (double)alignment)) - code_size;
for (size_t i = 0; i < padding_size; i++) {
m_code.push_back(m_al, 0);
}
EMIT("\n\talign " + std::to_string(alignment) + ", db 0");
}

void define_symbol(const std::string &name, uint32_t value) {
if (m_symbols.find(name) == m_symbols.end()) {
Symbol s;
Expand Down Expand Up @@ -548,22 +556,17 @@ class X86Assembler {
EMIT_LABEL(label + ":");
}

void add_var_size(const std::string &var) {
uint64_t val = pos() - origin();
// TODO: Support 64-bit or 8 byte parameter val in define_symbol()
define_symbol(var, val);
EMIT_VAR_SIZE(var);
}

void add_var64(const std::string &var, uint64_t val) {
void add_var64(const std::string &var, const std::string &start, const std::string &end) {
// TODO: Support 64-bit or 8 byte parameter val in define_symbol()
uint64_t val = get_defined_symbol(end).value - get_defined_symbol(start).value;
define_symbol(var, val);
EMIT_VAR(var, val);
EMIT_VAR(var, start, end);
}

void add_var(const std::string &var, uint32_t val) {
void add_var(const std::string &var, const std::string &start, const std::string &end) {
uint32_t val = get_defined_symbol(end).value - get_defined_symbol(start).value;
define_symbol(var, val);
EMIT_VAR(var, val);
EMIT_VAR(var, start, end);
}

uint32_t pos() {
Expand Down Expand Up @@ -1539,7 +1542,7 @@ void emit_print_float(X86Assembler &a, const std::string &name);
// Generate an ELF 64 bit header and footer
// With these two functions, one only must generate a `_start` assembly
// function to have a working binary on Linux.
void emit_elf64_header(X86Assembler &a, uint32_t p_flags=5);
void emit_elf64_header(X86Assembler &a);
void emit_elf64_footer(X86Assembler &a);

void emit_exit_64(X86Assembler &a, std::string label, int exit_code);
Expand Down
18 changes: 6 additions & 12 deletions src/lpython/tests/test_asm.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -403,9 +403,6 @@ BITS 32
dw 0x0000
dw 0x0000
dw 0x0000

ehdrsize equ 0x00000034

phdr:
dd 0x00000001
dd 0x00000000
Expand All @@ -415,12 +412,10 @@ ehdrsize equ 0x00000034
dd filesize
dd 0x00000005
dd 0x00001000

phdrsize equ 0x00000020


e_phoff equ 0x00000034

phdr_end:
ehdrsize equ phdr - ehdr
phdrsize equ phdr_end - phdr
e_phoff equ phdr - ehdr
msg:
db 0x48
db 0x65
Expand All @@ -446,9 +441,8 @@ e_phoff equ 0x00000034
mov eax, 0x00000001
mov ebx, 0x00000000
int 0x80

filesize equ $ - $$

footer:
filesize equ footer - ehdr
)""");
CHECK(asm_code == ref);
#endif
Expand Down