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-rw-r--r--compiler/elf_builder.h141
1 files changed, 55 insertions, 86 deletions
diff --git a/compiler/elf_builder.h b/compiler/elf_builder.h
index 6e8dfd60fb..bb07cc2913 100644
--- a/compiler/elf_builder.h
+++ b/compiler/elf_builder.h
@@ -23,10 +23,10 @@
#include "base/bit_utils.h"
#include "base/casts.h"
#include "base/unix_file/fd_file.h"
-#include "buffered_output_stream.h"
#include "elf_utils.h"
-#include "file_output_stream.h"
#include "leb128.h"
+#include "linker/error_delaying_output_stream.h"
+#include "utils/array_ref.h"
namespace art {
@@ -100,7 +100,7 @@ class ElfBuilder FINAL {
header_.sh_entsize = entsize;
}
- virtual ~Section() {
+ ~Section() OVERRIDE {
if (started_) {
CHECK(finished_);
}
@@ -120,8 +120,8 @@ class ElfBuilder FINAL {
sections.push_back(this);
// Align file position.
if (header_.sh_type != SHT_NOBITS) {
- header_.sh_offset = RoundUp(owner_->Seek(0, kSeekCurrent), header_.sh_addralign);
- owner_->Seek(header_.sh_offset, kSeekSet);
+ header_.sh_offset = RoundUp(owner_->stream_.Seek(0, kSeekCurrent), header_.sh_addralign);
+ owner_->stream_.Seek(header_.sh_offset, kSeekSet);
}
// Align virtual memory address.
if ((header_.sh_flags & SHF_ALLOC) != 0) {
@@ -139,7 +139,7 @@ class ElfBuilder FINAL {
CHECK_GT(header_.sh_size, 0u);
} else {
// Use the current file position to determine section size.
- off_t file_offset = owner_->Seek(0, kSeekCurrent);
+ off_t file_offset = owner_->stream_.Seek(0, kSeekCurrent);
CHECK_GE(file_offset, (off_t)header_.sh_offset);
header_.sh_size = file_offset - header_.sh_offset;
}
@@ -161,7 +161,7 @@ class ElfBuilder FINAL {
} else {
CHECK(started_);
CHECK_NE(header_.sh_type, (Elf_Word)SHT_NOBITS);
- return owner_->Seek(0, kSeekCurrent) - header_.sh_offset;
+ return owner_->stream_.Seek(0, kSeekCurrent) - header_.sh_offset;
}
}
@@ -176,15 +176,20 @@ class ElfBuilder FINAL {
bool WriteFully(const void* buffer, size_t byte_count) OVERRIDE {
CHECK(started_);
CHECK(!finished_);
- owner_->WriteFully(buffer, byte_count);
- return true;
+ return owner_->stream_.WriteFully(buffer, byte_count);
}
// This function always succeeds to simplify code.
// Use builder's Good() to check the actual status.
off_t Seek(off_t offset, Whence whence) OVERRIDE {
// Forward the seek as-is and trust the caller to use it reasonably.
- return owner_->Seek(offset, whence);
+ return owner_->stream_.Seek(offset, whence);
+ }
+
+ // This function flushes the output and returns whether it succeeded.
+ // If there was a previous failure, this does nothing and returns false, i.e. failed.
+ bool Flush() OVERRIDE {
+ return owner_->stream_.Flush();
}
Elf_Word GetSectionIndex() const {
@@ -270,26 +275,24 @@ class ElfBuilder FINAL {
};
ElfBuilder(InstructionSet isa, OutputStream* output)
- : isa_(isa),
- output_(output),
- output_good_(true),
- output_offset_(0),
- rodata_(this, ".rodata", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, kPageSize, 0),
- text_(this, ".text", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR, nullptr, 0, kPageSize, 0),
- bss_(this, ".bss", SHT_NOBITS, SHF_ALLOC, nullptr, 0, kPageSize, 0),
- dynstr_(this, ".dynstr", SHF_ALLOC, kPageSize),
- dynsym_(this, ".dynsym", SHT_DYNSYM, SHF_ALLOC, &dynstr_),
- hash_(this, ".hash", SHT_HASH, SHF_ALLOC, &dynsym_, 0, sizeof(Elf_Word), sizeof(Elf_Word)),
- dynamic_(this, ".dynamic", SHT_DYNAMIC, SHF_ALLOC, &dynstr_, 0, kPageSize, sizeof(Elf_Dyn)),
- eh_frame_(this, ".eh_frame", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, kPageSize, 0),
- eh_frame_hdr_(this, ".eh_frame_hdr", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, 4, 0),
- strtab_(this, ".strtab", 0, kPageSize),
- symtab_(this, ".symtab", SHT_SYMTAB, 0, &strtab_),
- debug_frame_(this, ".debug_frame", SHT_PROGBITS, 0, nullptr, 0, sizeof(Elf_Addr), 0),
- debug_info_(this, ".debug_info", SHT_PROGBITS, 0, nullptr, 0, 1, 0),
- debug_line_(this, ".debug_line", SHT_PROGBITS, 0, nullptr, 0, 1, 0),
- shstrtab_(this, ".shstrtab", 0, 1),
- virtual_address_(0) {
+ : isa_(isa),
+ stream_(output),
+ rodata_(this, ".rodata", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, kPageSize, 0),
+ text_(this, ".text", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR, nullptr, 0, kPageSize, 0),
+ bss_(this, ".bss", SHT_NOBITS, SHF_ALLOC, nullptr, 0, kPageSize, 0),
+ dynstr_(this, ".dynstr", SHF_ALLOC, kPageSize),
+ dynsym_(this, ".dynsym", SHT_DYNSYM, SHF_ALLOC, &dynstr_),
+ hash_(this, ".hash", SHT_HASH, SHF_ALLOC, &dynsym_, 0, sizeof(Elf_Word), sizeof(Elf_Word)),
+ dynamic_(this, ".dynamic", SHT_DYNAMIC, SHF_ALLOC, &dynstr_, 0, kPageSize, sizeof(Elf_Dyn)),
+ eh_frame_(this, ".eh_frame", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, kPageSize, 0),
+ eh_frame_hdr_(this, ".eh_frame_hdr", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, 4, 0),
+ strtab_(this, ".strtab", 0, kPageSize),
+ symtab_(this, ".symtab", SHT_SYMTAB, 0, &strtab_),
+ debug_frame_(this, ".debug_frame", SHT_PROGBITS, 0, nullptr, 0, sizeof(Elf_Addr), 0),
+ debug_info_(this, ".debug_info", SHT_PROGBITS, 0, nullptr, 0, 1, 0),
+ debug_line_(this, ".debug_line", SHT_PROGBITS, 0, nullptr, 0, 1, 0),
+ shstrtab_(this, ".shstrtab", 0, 1),
+ virtual_address_(0) {
text_.phdr_flags_ = PF_R | PF_X;
bss_.phdr_flags_ = PF_R | PF_W;
dynamic_.phdr_flags_ = PF_R | PF_W;
@@ -312,7 +315,7 @@ class ElfBuilder FINAL {
// Encode patch locations as LEB128 list of deltas between consecutive addresses.
// (exposed publicly for tests)
- static void EncodeOatPatches(const std::vector<uintptr_t>& locations,
+ static void EncodeOatPatches(const ArrayRef<const uintptr_t>& locations,
std::vector<uint8_t>* buffer) {
buffer->reserve(buffer->size() + locations.size() * 2); // guess 2 bytes per ULEB128.
uintptr_t address = 0; // relative to start of section.
@@ -323,9 +326,9 @@ class ElfBuilder FINAL {
}
}
- void WritePatches(const char* name, const std::vector<uintptr_t>* patch_locations) {
+ void WritePatches(const char* name, const ArrayRef<const uintptr_t>& patch_locations) {
std::vector<uint8_t> buffer;
- EncodeOatPatches(*patch_locations, &buffer);
+ EncodeOatPatches(patch_locations, &buffer);
std::unique_ptr<Section> s(new Section(this, name, SHT_OAT_PATCH, 0, nullptr, 0, 1, 0));
s->Start();
s->WriteFully(buffer.data(), buffer.size());
@@ -346,7 +349,7 @@ class ElfBuilder FINAL {
// We do not know the number of headers until later, so
// it is easiest to just reserve a fixed amount of space.
int size = sizeof(Elf_Ehdr) + sizeof(Elf_Phdr) * kMaxProgramHeaders;
- Seek(size, kSeekSet);
+ stream_.Seek(size, kSeekSet);
virtual_address_ += size;
}
@@ -370,9 +373,14 @@ class ElfBuilder FINAL {
shdrs.push_back(section->header_);
}
Elf_Off section_headers_offset;
- section_headers_offset = RoundUp(Seek(0, kSeekCurrent), sizeof(Elf_Off));
- Seek(section_headers_offset, kSeekSet);
- WriteFully(shdrs.data(), shdrs.size() * sizeof(shdrs[0]));
+ section_headers_offset = RoundUp(stream_.Seek(0, kSeekCurrent), sizeof(Elf_Off));
+ stream_.Seek(section_headers_offset, kSeekSet);
+ stream_.WriteFully(shdrs.data(), shdrs.size() * sizeof(shdrs[0]));
+
+ // Flush everything else before writing the program headers. This should prevent
+ // the OS from reordering writes, so that we don't end up with valid headers
+ // and partially written data if we suddenly lose power, for example.
+ stream_.Flush();
// Write the initial file headers.
std::vector<Elf_Phdr> phdrs = MakeProgramHeaders();
@@ -382,9 +390,10 @@ class ElfBuilder FINAL {
elf_header.e_phnum = phdrs.size();
elf_header.e_shnum = shdrs.size();
elf_header.e_shstrndx = shstrtab_.GetSectionIndex();
- Seek(0, kSeekSet);
- WriteFully(&elf_header, sizeof(elf_header));
- WriteFully(phdrs.data(), phdrs.size() * sizeof(phdrs[0]));
+ stream_.Seek(0, kSeekSet);
+ stream_.WriteFully(&elf_header, sizeof(elf_header));
+ stream_.WriteFully(phdrs.data(), phdrs.size() * sizeof(phdrs[0]));
+ stream_.Flush();
}
// The running program does not have access to section headers
@@ -462,53 +471,15 @@ class ElfBuilder FINAL {
// Returns true if all writes and seeks on the output stream succeeded.
bool Good() {
- return output_good_;
- }
-
- private:
- // This function always succeeds to simplify code.
- // Use Good() to check the actual status of the output stream.
- void WriteFully(const void* buffer, size_t byte_count) {
- if (output_good_) {
- if (!output_->WriteFully(buffer, byte_count)) {
- PLOG(ERROR) << "Failed to write " << byte_count
- << " bytes to ELF file at offset " << output_offset_;
- output_good_ = false;
- }
- }
- output_offset_ += byte_count;
+ return stream_.Good();
}
- // This function always succeeds to simplify code.
- // Use Good() to check the actual status of the output stream.
- off_t Seek(off_t offset, Whence whence) {
- // We keep shadow copy of the offset so that we return
- // the expected value even if the output stream failed.
- off_t new_offset;
- switch (whence) {
- case kSeekSet:
- new_offset = offset;
- break;
- case kSeekCurrent:
- new_offset = output_offset_ + offset;
- break;
- default:
- LOG(FATAL) << "Unsupported seek type: " << whence;
- UNREACHABLE();
- }
- if (output_good_) {
- off_t actual_offset = output_->Seek(offset, whence);
- if (actual_offset == (off_t)-1) {
- PLOG(ERROR) << "Failed to seek in ELF file. Offset=" << offset
- << " whence=" << whence << " new_offset=" << new_offset;
- output_good_ = false;
- }
- DCHECK_EQ(actual_offset, new_offset);
- }
- output_offset_ = new_offset;
- return new_offset;
+ // Returns the builder's internal stream.
+ OutputStream* GetStream() {
+ return &stream_;
}
+ private:
static Elf_Ehdr MakeElfHeader(InstructionSet isa) {
Elf_Ehdr elf_header = Elf_Ehdr();
switch (isa) {
@@ -660,9 +631,7 @@ class ElfBuilder FINAL {
InstructionSet isa_;
- OutputStream* output_;
- bool output_good_; // True if all writes to output succeeded.
- off_t output_offset_; // Keep track of the current position in the stream.
+ ErrorDelayingOutputStream stream_;
Section rodata_;
Section text_;
generated by cgit v1.2.3-59-g8ed1b (git 2.39.0) at 2025-12-06 12:42:29 +0000