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Bulk file reads in INCBIN
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Again, this should improve performance, notably from bypassing
stdio's buffering layer (we are generally able to use more
appropriate buffer sizes, and also to write bytes directly to
their final destination).
And perhaps it might also improve reliability somewhat.
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@ISSOtm @Rangi42
ISSOtm authored and Rangi42 committed Aug 27, 2024
1 parent 7553241 commit 0ac8cf2
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Showing 3 changed files with 101 additions and 78 deletions.
175 changes: 99 additions & 76 deletions src/asm/section.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3,8 +3,10 @@
#include "asm/section.hpp"

#include <algorithm>
#include <cerrno>
#include <cstdint>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <optional>
#include <stack>
Expand All @@ -14,6 +16,7 @@

#include "helpers.hpp"
#include "linkdefs.hpp"
#include "platform.hpp"

#include "asm/fstack.hpp"
#include "asm/lexer.hpp"
Expand Down Expand Up @@ -839,54 +842,83 @@ void sect_BinaryFile(std::string const &name, int32_t startPos) {
if (!requireCodeSection())
return;

FILE *file = nullptr;
int file = -1;
if (std::optional<std::string> fullPath = fstk_FindFile(name); fullPath)
file = fopen(fullPath->c_str(), "rb");
if (!file) {
file = open(fullPath->c_str(), O_RDONLY | O_BINARY);
if (file < 0) {
if (generatedMissingIncludes) {
if (verbose)
printf("Aborting (-MG) on INCBIN file '%s' (%s)\n", name.c_str(), strerror(errno));
printf("Aborting (-MG) on INCBIN file \"%s\" (%s)\n", name.c_str(), strerror(errno));
failedOnMissingInclude = true;
} else {
error("Error opening INCBIN file '%s': %s\n", name.c_str(), strerror(errno));
error("Error opening INCBIN file \"%s\": %s\n", name.c_str(), strerror(errno));
}
return;
}
Defer closeFile{[&] { fclose(file); }};
Defer closeFile{[&] { close(file); }};

if (fseek(file, 0, SEEK_END) != -1) {
if (startPos > ftell(file)) {
error("Specified start position is greater than length of file '%s'\n", name.c_str());
return;
}
// The file is seekable; skip to the specified start position
fseek(file, startPos, SEEK_SET);
} else {
if (errno != ESPIPE)
char buf[BUFSIZ];
// The file isn't seekable, so we'll just skip bytes one at a time
while (startPos) {
int nbRead = read(file, buf, std::min(startPos + size_t(0), sizeof(buf)));
if (nbRead == 0) { // EOF
error(
"Error determining size of INCBIN file '%s': %s\n", name.c_str(), strerror(errno)
"Starting offset is %" PRIu32 " bytes past the end of INCBIN file \"%s\"",
startPos,
name.c_str()
);
// The file isn't seekable, so we'll just skip bytes one at a time
while (startPos--) {
if (fgetc(file) == EOF) {
error(
"Specified start position is greater than length of file '%s'\n", name.c_str()
);
return;
} else if (nbRead == -1 && errno != EINTR) {
error("Error reading INCBIN file \"%s\": %s\n", name.c_str(), strerror(errno));
return;
} else if (nbRead != -1) {
startPos -= nbRead;
}
// Just discard the bytes that were just read.
}

// Try to bulk reads from the file, to maximise efficiency.
// To that effect, we'll set the section to its maximum size, and read as many bytes as possible
uint16_t const maxSize = sectionTypeInfo[currentSection->type].size;
if (currentSection->size < maxSize) {
// Set the section to its maximum size possible, to give the file a chance to fill up as
// much as reasonably feasible.
currentSection->data.resize(maxSize);
uint8_t *bytes = &currentSection->data[currentSection->size];
uint16_t len = maxSize - currentSection->size; // How many bytes have been made available.
for (;;) {
int nbRead = read(file, bytes, len);
if (nbRead == 0) { // EOF
break;
} else if (nbRead == -1 && errno != EINTR) {
error("Error reading INCBIN file \"%s\": %s\n", name.c_str(), strerror(errno));
return;
} else if (nbRead != -1) {
len -= nbRead;
if (len == 0) {
break;
}
bytes += nbRead;
}
}
growSection(maxSize - currentSection->size - len);
currentSection->data.resize(currentSection->size);
}

for (int byte; (byte = fgetc(file)) != EOF;) {
uint8_t *bytes = reserveBytes(1);
if (bytes == nullptr)
return;
*bytes = byte;
growSection(1);
if (currentSection->size >= maxSize) {
// If we read even just a single byte more, the section will overflow!
for (;;) {
int nbRead = read(file, buf, sizeof(buf));
if (nbRead == 0) { // EOF
break;
} else if (nbRead == -1 && errno != EINTR) {
error("Error reading INCBIN file \"%s\": %s\n", name.c_str(), strerror(errno));
return;
} else if (nbRead != -1) {
growSection(nbRead);
}
}
}

if (ferror(file))
error("Error reading INCBIN file '%s': %s\n", name.c_str(), strerror(errno));
}

// Output a slice of a binary file
Expand All @@ -899,74 +931,65 @@ void sect_BinaryFileSlice(std::string const &name, int32_t startPos, int32_t len
error("Number of bytes to read cannot be negative (%" PRId32 ")\n", length);
length = 0;
}
if (!requireCodeSection())
uint8_t *bytes = reserveBytes(length);
if (bytes == nullptr)
return;
growSection(length); // We are able to immediately grow the section accordingly.
if (length == 0) // Don't even bother with 0-byte slices
return;

FILE *file = nullptr;
int file = -1;
if (std::optional<std::string> fullPath = fstk_FindFile(name); fullPath)
file = fopen(fullPath->c_str(), "rb");
if (!file) {
file = open(fullPath->c_str(), O_RDONLY | O_BINARY);
if (file < 0) {
if (generatedMissingIncludes) {
if (verbose)
printf("Aborting (-MG) on INCBIN file '%s' (%s)\n", name.c_str(), strerror(errno));
printf("Aborting (-MG) on INCBIN file \"%s\" (%s)\n", name.c_str(), strerror(errno));
failedOnMissingInclude = true;
} else {
error("Error opening INCBIN file '%s': %s\n", name.c_str(), strerror(errno));
error("Error opening INCBIN file \"%s\": %s\n", name.c_str(), strerror(errno));
}
return;
}
Defer closeFile{[&] { fclose(file); }};
Defer closeFile{[&] { close(file); }};

if (fseek(file, 0, SEEK_END) != -1) {
if (int32_t fsize = ftell(file); startPos > fsize) {
error("Specified start position is greater than length of file '%s'\n", name.c_str());
return;
} else if (startPos + length > fsize) {
char buf[BUFSIZ];
// The file isn't seekable, so we'll just skip bytes one at a time
while (startPos) {
int nbRead = read(file, buf, std::min(startPos + size_t(0), sizeof(buf)));
if (nbRead == 0) { // EOF
error(
"Specified range in INCBIN file '%s' is out of bounds (%" PRIu32 " + %" PRIu32
" > %" PRIu32 ")\n",
name.c_str(),
"Starting offset is %" PRIu32 " byte%s past the end of INCBIN file \"%s\"",
startPos,
length,
fsize
startPos == 1 ? "" : "s",
name.c_str()
);
return;
} else if (nbRead == -1 && errno != EINTR) {
error("Error reading INCBIN file \"%s\": %s\n", name.c_str(), strerror(errno));
return;
} else if (nbRead != -1) {
startPos -= nbRead;
}
// The file is seekable; skip to the specified start position
fseek(file, startPos, SEEK_SET);
} else {
if (errno != ESPIPE)
error(
"Error determining size of INCBIN file '%s': %s\n", name.c_str(), strerror(errno)
);
// The file isn't seekable, so we'll just skip bytes one at a time
while (startPos--) {
if (fgetc(file) == EOF) {
error(
"Specified start position is greater than length of file '%s'\n", name.c_str()
);
return;
}
}
// Just discard the bytes that were just read.
}

while (length--) {
if (int byte = fgetc(file); byte != EOF) {
uint8_t *bytes = reserveBytes(1);
if (bytes == nullptr)
return;
*bytes = byte;
growSection(1);
} else if (ferror(file)) {
error("Error reading INCBIN file '%s': %s\n", name.c_str(), strerror(errno));
} else {
while (length) {
int nbRead = read(file, bytes, length);
if (nbRead == 0) { // EOF
error(
"Premature end of INCBIN file '%s' (%" PRId32 " bytes left to read)\n",
"Premature end of INCBIN file \"%s\" (%" PRId32 " byte%s left to read)\n",
name.c_str(),
length + 1
length,
length == 1 ? "" : "s"
);
return;
} else if (nbRead == -1 && errno != EINTR) {
error("Error reading INCBIN file \"%s\": %s\n", name.c_str(), strerror(errno));
return;
} else if (nbRead != -1) {
length -= nbRead;
bytes += nbRead;
}
}
}
Expand Down
2 changes: 1 addition & 1 deletion test/asm/incbin-empty-bad.err
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Original file line number Diff line number Diff line change
@@ -1,3 +1,3 @@
error: incbin-empty-bad.asm(3):
Specified range in INCBIN file 'empty.bin' is out of bounds (0 + 1 > 0)
Premature end of INCBIN file "empty.bin" (1 byte left to read)
error: Assembly aborted (1 error)!
2 changes: 1 addition & 1 deletion test/asm/incbin-end-bad.err
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Original file line number Diff line number Diff line change
@@ -1,3 +1,3 @@
error: incbin-end-bad.asm(3):
Specified range in INCBIN file 'data.bin' is out of bounds (123 + 1 > 123)
Premature end of INCBIN file "data.bin" (1 byte left to read)
error: Assembly aborted (1 error)!

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