2009-02-03 15:13:24 +08:00
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//===-- gold-plugin.cpp - Plugin to gold for Link Time Optimization ------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This is a gold plugin for LLVM. It provides an LLVM implementation of the
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// interface described in http://gcc.gnu.org/wiki/whopr/driver .
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//
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//===----------------------------------------------------------------------===//
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#include "plugin-api.h"
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#include "llvm-c/lto.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/System/Path.h"
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2009-02-05 05:00:02 +08:00
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#include <cerrno>
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2009-02-03 15:13:24 +08:00
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#include <cstdlib>
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#include <cstring>
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2009-02-23 06:15:44 +08:00
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#include <fstream>
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2009-02-03 15:13:24 +08:00
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#include <list>
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#include <vector>
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using namespace llvm;
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namespace {
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ld_plugin_status discard_message(int level, const char *format, ...) {
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// Die loudly. Recent versions of Gold pass ld_plugin_message as the first
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// callback in the transfer vector. This should never be called.
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abort();
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}
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ld_plugin_add_symbols add_symbols = NULL;
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ld_plugin_get_symbols get_symbols = NULL;
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ld_plugin_add_input_file add_input_file = NULL;
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ld_plugin_message message = discard_message;
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int api_version = 0;
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int gold_version = 0;
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2009-02-23 06:15:44 +08:00
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bool generate_api_file = false;
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2009-02-03 15:13:24 +08:00
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struct claimed_file {
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lto_module_t M;
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void *handle;
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std::vector<ld_plugin_symbol> syms;
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};
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lto_codegen_model output_type = LTO_CODEGEN_PIC_MODEL_STATIC;
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std::list<claimed_file> Modules;
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std::vector<sys::Path> Cleanup;
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}
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ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
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int *claimed);
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ld_plugin_status all_symbols_read_hook(void);
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ld_plugin_status cleanup_hook(void);
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extern "C" ld_plugin_status onload(ld_plugin_tv *tv);
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ld_plugin_status onload(ld_plugin_tv *tv) {
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// We're given a pointer to the first transfer vector. We read through them
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// until we find one where tv_tag == LDPT_NULL. The REGISTER_* tagged values
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// contain pointers to functions that we need to call to register our own
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// hooks. The others are addresses of functions we can use to call into gold
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// for services.
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bool registeredClaimFile = false;
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bool registeredAllSymbolsRead = false;
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bool registeredCleanup = false;
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for (; tv->tv_tag != LDPT_NULL; ++tv) {
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switch (tv->tv_tag) {
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case LDPT_API_VERSION:
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api_version = tv->tv_u.tv_val;
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break;
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case LDPT_GOLD_VERSION: // major * 100 + minor
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gold_version = tv->tv_u.tv_val;
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break;
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case LDPT_LINKER_OUTPUT:
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switch (tv->tv_u.tv_val) {
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case LDPO_REL: // .o
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case LDPO_DYN: // .so
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output_type = LTO_CODEGEN_PIC_MODEL_DYNAMIC;
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break;
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case LDPO_EXEC: // .exe
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output_type = LTO_CODEGEN_PIC_MODEL_STATIC;
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break;
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default:
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(*message)(LDPL_ERROR, "Unknown output file type %d",
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tv->tv_u.tv_val);
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return LDPS_ERR;
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}
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// TODO: add an option to disable PIC.
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//output_type = LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC;
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break;
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case LDPT_OPTION:
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2009-02-23 06:15:44 +08:00
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if (strcmp("generate-api-file", tv->tv_u.tv_string) == 0) {
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generate_api_file = true;
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} else {
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(*message)(LDPL_WARNING, "Ignoring flag %s", tv->tv_u.tv_string);
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}
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2009-02-03 15:13:24 +08:00
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break;
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case LDPT_REGISTER_CLAIM_FILE_HOOK: {
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ld_plugin_register_claim_file callback;
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callback = tv->tv_u.tv_register_claim_file;
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if ((*callback)(claim_file_hook) != LDPS_OK)
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return LDPS_ERR;
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registeredClaimFile = true;
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} break;
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case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK: {
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ld_plugin_register_all_symbols_read callback;
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callback = tv->tv_u.tv_register_all_symbols_read;
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if ((*callback)(all_symbols_read_hook) != LDPS_OK)
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return LDPS_ERR;
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registeredAllSymbolsRead = true;
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} break;
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case LDPT_REGISTER_CLEANUP_HOOK: {
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ld_plugin_register_cleanup callback;
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callback = tv->tv_u.tv_register_cleanup;
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if ((*callback)(cleanup_hook) != LDPS_OK)
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return LDPS_ERR;
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registeredCleanup = true;
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} break;
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case LDPT_ADD_SYMBOLS:
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add_symbols = tv->tv_u.tv_add_symbols;
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break;
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case LDPT_GET_SYMBOLS:
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get_symbols = tv->tv_u.tv_get_symbols;
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break;
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case LDPT_ADD_INPUT_FILE:
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add_input_file = tv->tv_u.tv_add_input_file;
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break;
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case LDPT_MESSAGE:
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message = tv->tv_u.tv_message;
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break;
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default:
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break;
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}
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}
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2009-02-18 16:30:15 +08:00
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if (!registeredClaimFile) {
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2009-02-19 01:49:06 +08:00
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(*message)(LDPL_ERROR, "register_claim_file not passed to LLVMgold.");
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return LDPS_ERR;
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}
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2009-02-18 16:30:15 +08:00
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if (!add_symbols) {
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2009-02-19 01:49:06 +08:00
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(*message)(LDPL_ERROR, "add_symbols not passed to LLVMgold.");
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return LDPS_ERR;
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}
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2009-02-03 15:13:24 +08:00
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return LDPS_OK;
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}
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/// claim_file_hook - called by gold to see whether this file is one that
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/// our plugin can handle. We'll try to open it and register all the symbols
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/// with add_symbol if possible.
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ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
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int *claimed) {
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2009-02-05 01:39:30 +08:00
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void *buf = NULL;
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if (file->offset) {
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2009-02-05 12:14:23 +08:00
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// Gold has found what might be IR part-way inside of a file, such as
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// an .a archive.
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2009-02-05 01:39:30 +08:00
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if (lseek(file->fd, file->offset, SEEK_SET) == -1) {
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2009-02-07 11:15:01 +08:00
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(*message)(LDPL_ERROR,
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2009-02-05 01:39:30 +08:00
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"Failed to seek to archive member of %s at offset %d: %s\n",
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file->name,
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file->offset, strerror(errno));
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return LDPS_ERR;
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}
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buf = malloc(file->filesize);
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if (!buf) {
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2009-02-07 11:15:01 +08:00
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(*message)(LDPL_ERROR,
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2009-02-05 01:39:30 +08:00
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"Failed to allocate buffer for archive member of size: %d\n",
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file->filesize);
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return LDPS_ERR;
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}
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if (read(file->fd, buf, file->filesize) != file->filesize) {
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2009-02-07 11:15:01 +08:00
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(*message)(LDPL_ERROR,
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"Failed to read archive member of %s at offset %d: %s\n",
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2009-02-05 01:39:30 +08:00
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file->name,
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2009-02-07 11:15:01 +08:00
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file->offset,
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2009-02-05 01:39:30 +08:00
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strerror(errno));
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2009-02-07 11:15:01 +08:00
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free(buf);
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2009-02-05 01:39:30 +08:00
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return LDPS_ERR;
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}
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2009-02-07 11:15:01 +08:00
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if (!lto_module_is_object_file_in_memory(buf, file->filesize)) {
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free(buf);
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2009-02-05 01:39:30 +08:00
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return LDPS_OK;
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2009-02-07 11:15:01 +08:00
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}
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2009-02-05 01:39:30 +08:00
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} else if (!lto_module_is_object_file(file->name))
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2009-02-03 15:13:24 +08:00
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return LDPS_OK;
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*claimed = 1;
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Modules.resize(Modules.size() + 1);
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claimed_file &cf = Modules.back();
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2009-02-05 12:14:23 +08:00
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cf.M = buf ? lto_module_create_from_memory(buf, file->filesize) :
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lto_module_create(file->name);
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2009-02-06 09:58:34 +08:00
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free(buf);
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2009-02-03 15:13:24 +08:00
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if (!cf.M) {
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(*message)(LDPL_ERROR, "Failed to create LLVM module: %s",
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lto_get_error_message());
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return LDPS_ERR;
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}
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cf.handle = file->handle;
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unsigned sym_count = lto_module_get_num_symbols(cf.M);
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cf.syms.reserve(sym_count);
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for (unsigned i = 0; i != sym_count; ++i) {
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lto_symbol_attributes attrs = lto_module_get_symbol_attribute(cf.M, i);
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if ((attrs & LTO_SYMBOL_SCOPE_MASK) == LTO_SYMBOL_SCOPE_INTERNAL)
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continue;
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cf.syms.push_back(ld_plugin_symbol());
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ld_plugin_symbol &sym = cf.syms.back();
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sym.name = const_cast<char *>(lto_module_get_symbol_name(cf.M, i));
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sym.version = NULL;
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int scope = attrs & LTO_SYMBOL_SCOPE_MASK;
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switch (scope) {
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case LTO_SYMBOL_SCOPE_HIDDEN:
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sym.visibility = LDPV_HIDDEN;
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break;
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case LTO_SYMBOL_SCOPE_PROTECTED:
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sym.visibility = LDPV_PROTECTED;
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break;
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case 0: // extern
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case LTO_SYMBOL_SCOPE_DEFAULT:
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sym.visibility = LDPV_DEFAULT;
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break;
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default:
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(*message)(LDPL_ERROR, "Unknown scope attribute: %d", scope);
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return LDPS_ERR;
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}
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int definition = attrs & LTO_SYMBOL_DEFINITION_MASK;
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switch (definition) {
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case LTO_SYMBOL_DEFINITION_REGULAR:
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sym.def = LDPK_DEF;
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break;
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case LTO_SYMBOL_DEFINITION_UNDEFINED:
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sym.def = LDPK_UNDEF;
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break;
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case LTO_SYMBOL_DEFINITION_TENTATIVE:
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sym.def = LDPK_COMMON;
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break;
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case LTO_SYMBOL_DEFINITION_WEAK:
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sym.def = LDPK_WEAKDEF;
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break;
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default:
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(*message)(LDPL_ERROR, "Unknown definition attribute: %d", definition);
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return LDPS_ERR;
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}
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// LLVM never emits COMDAT.
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sym.size = 0;
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sym.comdat_key = NULL;
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sym.resolution = LDPR_UNKNOWN;
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}
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cf.syms.reserve(cf.syms.size());
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if (!cf.syms.empty()) {
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if ((*add_symbols)(cf.handle, cf.syms.size(), &cf.syms[0]) != LDPS_OK) {
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(*message)(LDPL_ERROR, "Unable to add symbols!");
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return LDPS_ERR;
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}
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}
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return LDPS_OK;
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}
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/// all_symbols_read_hook - gold informs us that all symbols have been read.
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/// At this point, we use get_symbols to see if any of our definitions have
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/// been overridden by a native object file. Then, perform optimization and
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/// codegen.
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ld_plugin_status all_symbols_read_hook(void) {
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lto_code_gen_t cg = lto_codegen_create();
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for (std::list<claimed_file>::iterator I = Modules.begin(),
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E = Modules.end(); I != E; ++I)
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lto_codegen_add_module(cg, I->M);
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2009-02-23 06:15:44 +08:00
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std::ofstream api_file;
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if (generate_api_file) {
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api_file.open("apifile.txt", std::ofstream::out | std::ofstream::trunc);
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if (!api_file.is_open()) {
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(*message)(LDPL_FATAL, "Unable to open apifile.txt for writing.");
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abort();
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}
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}
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2009-02-03 15:13:24 +08:00
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// If we don't preserve any symbols, libLTO will assume that all symbols are
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// needed. Keep all symbols unless we're producing a final executable.
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if (output_type == LTO_CODEGEN_PIC_MODEL_STATIC) {
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bool anySymbolsPreserved = false;
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for (std::list<claimed_file>::iterator I = Modules.begin(),
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E = Modules.end(); I != E; ++I) {
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(*get_symbols)(I->handle, I->syms.size(), &I->syms[0]);
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for (unsigned i = 0, e = I->syms.size(); i != e; i++) {
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2009-02-16 06:49:17 +08:00
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if (I->syms[i].resolution == LDPR_PREVAILING_DEF ||
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(I->syms[i].def == LDPK_COMMON &&
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I->syms[i].resolution == LDPR_RESOLVED_IR)) {
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2009-02-03 15:13:24 +08:00
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lto_codegen_add_must_preserve_symbol(cg, I->syms[i].name);
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anySymbolsPreserved = true;
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2009-02-23 06:15:44 +08:00
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if (generate_api_file)
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api_file << I->syms[i].name << "\n";
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2009-02-03 15:13:24 +08:00
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}
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}
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}
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2009-02-23 06:15:44 +08:00
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if (generate_api_file)
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api_file.close();
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2009-02-03 15:13:24 +08:00
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if (!anySymbolsPreserved) {
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// This entire file is unnecessary!
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lto_codegen_dispose(cg);
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return LDPS_OK;
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}
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}
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lto_codegen_set_pic_model(cg, output_type);
|
|
|
|
lto_codegen_set_debug_model(cg, LTO_DEBUG_MODEL_DWARF);
|
|
|
|
|
|
|
|
size_t bufsize = 0;
|
|
|
|
const char *buffer = static_cast<const char *>(lto_codegen_compile(cg,
|
|
|
|
&bufsize));
|
|
|
|
|
|
|
|
std::string ErrMsg;
|
|
|
|
|
|
|
|
sys::Path uniqueObjPath("/tmp/llvmgold.o");
|
|
|
|
if (uniqueObjPath.createTemporaryFileOnDisk(true, &ErrMsg)) {
|
|
|
|
(*message)(LDPL_ERROR, "%s", ErrMsg.c_str());
|
|
|
|
return LDPS_ERR;
|
|
|
|
}
|
|
|
|
raw_fd_ostream *objFile = new raw_fd_ostream(uniqueObjPath.c_str(), true,
|
|
|
|
ErrMsg);
|
|
|
|
if (!ErrMsg.empty()) {
|
|
|
|
delete objFile;
|
|
|
|
(*message)(LDPL_ERROR, "%s", ErrMsg.c_str());
|
|
|
|
return LDPS_ERR;
|
|
|
|
}
|
|
|
|
|
|
|
|
objFile->write(buffer, bufsize);
|
|
|
|
objFile->close();
|
|
|
|
|
|
|
|
lto_codegen_dispose(cg);
|
|
|
|
|
|
|
|
if ((*add_input_file)(const_cast<char*>(uniqueObjPath.c_str())) != LDPS_OK) {
|
|
|
|
(*message)(LDPL_ERROR, "Unable to add .o file to the link.");
|
|
|
|
(*message)(LDPL_ERROR, "File left behind in: %s", uniqueObjPath.c_str());
|
|
|
|
return LDPS_ERR;
|
|
|
|
}
|
|
|
|
|
|
|
|
Cleanup.push_back(uniqueObjPath);
|
|
|
|
|
|
|
|
return LDPS_OK;
|
|
|
|
}
|
|
|
|
|
|
|
|
ld_plugin_status cleanup_hook(void) {
|
|
|
|
std::string ErrMsg;
|
|
|
|
|
|
|
|
for (int i = 0, e = Cleanup.size(); i != e; ++i)
|
|
|
|
if (Cleanup[i].eraseFromDisk(false, &ErrMsg))
|
|
|
|
(*message)(LDPL_ERROR, "Failed to delete '%s': %s", Cleanup[i].c_str(),
|
|
|
|
ErrMsg.c_str());
|
|
|
|
|
|
|
|
return LDPS_OK;
|
|
|
|
}
|