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+//===- ScriptParser.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains a recursive-descendent parser for linker scripts.
+// Parsed results are stored to Config and Script global objects.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ScriptParser.h"
+#include "Config.h"
+#include "Driver.h"
+#include "InputSection.h"
+#include "LinkerScript.h"
+#include "OutputSections.h"
+#include "ScriptLexer.h"
+#include "Symbols.h"
+#include "Target.h"
+#include "lld/Common/Memory.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSet.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include <cassert>
+#include <limits>
+#include <vector>
+
+using namespace llvm;
+using namespace llvm::ELF;
+using namespace llvm::support::endian;
+using namespace lld;
+using namespace lld::elf;
+
+namespace {
+class ScriptParser final : ScriptLexer {
+public:
+ ScriptParser(MemoryBufferRef mb) : ScriptLexer(mb) {
+ // Initialize IsUnderSysroot
+ if (config->sysroot == "")
+ return;
+ StringRef path = mb.getBufferIdentifier();
+ for (; !path.empty(); path = sys::path::parent_path(path)) {
+ if (!sys::fs::equivalent(config->sysroot, path))
+ continue;
+ isUnderSysroot = true;
+ return;
+ }
+ }
+
+ void readLinkerScript();
+ void readVersionScript();
+ void readDynamicList();
+ void readDefsym(StringRef name);
+
+private:
+ void addFile(StringRef path);
+
+ void readAsNeeded();
+ void readEntry();
+ void readExtern();
+ void readGroup();
+ void readInclude();
+ void readInput();
+ void readMemory();
+ void readOutput();
+ void readOutputArch();
+ void readOutputFormat();
+ void readPhdrs();
+ void readRegionAlias();
+ void readSearchDir();
+ void readSections();
+ void readTarget();
+ void readVersion();
+ void readVersionScriptCommand();
+
+ SymbolAssignment *readSymbolAssignment(StringRef name);
+ ByteCommand *readByteCommand(StringRef tok);
+ std::array<uint8_t, 4> readFill();
+ bool readSectionDirective(OutputSection *cmd, StringRef tok1, StringRef tok2);
+ void readSectionAddressType(OutputSection *cmd);
+ OutputSection *readOverlaySectionDescription();
+ OutputSection *readOutputSectionDescription(StringRef outSec);
+ std::vector<BaseCommand *> readOverlay();
+ std::vector<StringRef> readOutputSectionPhdrs();
+ InputSectionDescription *readInputSectionDescription(StringRef tok);
+ StringMatcher readFilePatterns();
+ std::vector<SectionPattern> readInputSectionsList();
+ InputSectionDescription *readInputSectionRules(StringRef filePattern);
+ unsigned readPhdrType();
+ SortSectionPolicy readSortKind();
+ SymbolAssignment *readProvideHidden(bool provide, bool hidden);
+ SymbolAssignment *readAssignment(StringRef tok);
+ void readSort();
+ Expr readAssert();
+ Expr readConstant();
+ Expr getPageSize();
+
+ uint64_t readMemoryAssignment(StringRef, StringRef, StringRef);
+ std::pair<uint32_t, uint32_t> readMemoryAttributes();
+
+ Expr combine(StringRef op, Expr l, Expr r);
+ Expr readExpr();
+ Expr readExpr1(Expr lhs, int minPrec);
+ StringRef readParenLiteral();
+ Expr readPrimary();
+ Expr readTernary(Expr cond);
+ Expr readParenExpr();
+
+ // For parsing version script.
+ std::vector<SymbolVersion> readVersionExtern();
+ void readAnonymousDeclaration();
+ void readVersionDeclaration(StringRef verStr);
+
+ std::pair<std::vector<SymbolVersion>, std::vector<SymbolVersion>>
+ readSymbols();
+
+ // True if a script being read is in a subdirectory specified by -sysroot.
+ bool isUnderSysroot = false;
+
+ // A set to detect an INCLUDE() cycle.
+ StringSet<> seen;
+};
+} // namespace
+
+static StringRef unquote(StringRef s) {
+ if (s.startswith("\""))
+ return s.substr(1, s.size() - 2);
+ return s;
+}
+
+// Some operations only support one non absolute value. Move the
+// absolute one to the right hand side for convenience.
+static void moveAbsRight(ExprValue &a, ExprValue &b) {
+ if (a.sec == nullptr || (a.forceAbsolute && !b.isAbsolute()))
+ std::swap(a, b);
+ if (!b.isAbsolute())
+ error(a.loc + ": at least one side of the expression must be absolute");
+}
+
+static ExprValue add(ExprValue a, ExprValue b) {
+ moveAbsRight(a, b);
+ return {a.sec, a.forceAbsolute, a.getSectionOffset() + b.getValue(), a.loc};
+}
+
+static ExprValue sub(ExprValue a, ExprValue b) {
+ // The distance between two symbols in sections is absolute.
+ if (!a.isAbsolute() && !b.isAbsolute())
+ return a.getValue() - b.getValue();
+ return {a.sec, false, a.getSectionOffset() - b.getValue(), a.loc};
+}
+
+static ExprValue bitAnd(ExprValue a, ExprValue b) {
+ moveAbsRight(a, b);
+ return {a.sec, a.forceAbsolute,
+ (a.getValue() & b.getValue()) - a.getSecAddr(), a.loc};
+}
+
+static ExprValue bitOr(ExprValue a, ExprValue b) {
+ moveAbsRight(a, b);
+ return {a.sec, a.forceAbsolute,
+ (a.getValue() | b.getValue()) - a.getSecAddr(), a.loc};
+}
+
+void ScriptParser::readDynamicList() {
+ config->hasDynamicList = true;
+ expect("{");
+ std::vector<SymbolVersion> locals;
+ std::vector<SymbolVersion> globals;
+ std::tie(locals, globals) = readSymbols();
+ expect(";");
+
+ if (!atEOF()) {
+ setError("EOF expected, but got " + next());
+ return;
+ }
+ if (!locals.empty()) {
+ setError("\"local:\" scope not supported in --dynamic-list");
+ return;
+ }
+
+ for (SymbolVersion v : globals)
+ config->dynamicList.push_back(v);
+}
+
+void ScriptParser::readVersionScript() {
+ readVersionScriptCommand();
+ if (!atEOF())
+ setError("EOF expected, but got " + next());
+}
+
+void ScriptParser::readVersionScriptCommand() {
+ if (consume("{")) {
+ readAnonymousDeclaration();
+ return;
+ }
+
+ while (!atEOF() && !errorCount() && peek() != "}") {
+ StringRef verStr = next();
+ if (verStr == "{") {
+ setError("anonymous version definition is used in "
+ "combination with other version definitions");
+ return;
+ }
+ expect("{");
+ readVersionDeclaration(verStr);
+ }
+}
+
+void ScriptParser::readVersion() {
+ expect("{");
+ readVersionScriptCommand();
+ expect("}");
+}
+
+void ScriptParser::readLinkerScript() {
+ while (!atEOF()) {
+ StringRef tok = next();
+ if (tok == ";")
+ continue;
+
+ if (tok == "ENTRY") {
+ readEntry();
+ } else if (tok == "EXTERN") {
+ readExtern();
+ } else if (tok == "GROUP") {
+ readGroup();
+ } else if (tok == "INCLUDE") {
+ readInclude();
+ } else if (tok == "INPUT") {
+ readInput();
+ } else if (tok == "MEMORY") {
+ readMemory();
+ } else if (tok == "OUTPUT") {
+ readOutput();
+ } else if (tok == "OUTPUT_ARCH") {
+ readOutputArch();
+ } else if (tok == "OUTPUT_FORMAT") {
+ readOutputFormat();
+ } else if (tok == "PHDRS") {
+ readPhdrs();
+ } else if (tok == "REGION_ALIAS") {
+ readRegionAlias();
+ } else if (tok == "SEARCH_DIR") {
+ readSearchDir();
+ } else if (tok == "SECTIONS") {
+ readSections();
+ } else if (tok == "TARGET") {
+ readTarget();
+ } else if (tok == "VERSION") {
+ readVersion();
+ } else if (SymbolAssignment *cmd = readAssignment(tok)) {
+ script->sectionCommands.push_back(cmd);
+ } else {
+ setError("unknown directive: " + tok);
+ }
+ }
+}
+
+void ScriptParser::readDefsym(StringRef name) {
+ if (errorCount())
+ return;
+ Expr e = readExpr();
+ if (!atEOF())
+ setError("EOF expected, but got " + next());
+ SymbolAssignment *cmd = make<SymbolAssignment>(name, e, getCurrentLocation());
+ script->sectionCommands.push_back(cmd);
+}
+
+void ScriptParser::addFile(StringRef s) {
+ if (isUnderSysroot && s.startswith("/")) {
+ SmallString<128> pathData;
+ StringRef path = (config->sysroot + s).toStringRef(pathData);
+ if (sys::fs::exists(path)) {
+ driver->addFile(saver.save(path), /*withLOption=*/false);
+ return;
+ }
+ }
+
+ if (s.startswith("/")) {
+ driver->addFile(s, /*withLOption=*/false);
+ } else if (s.startswith("=")) {
+ if (config->sysroot.empty())
+ driver->addFile(s.substr(1), /*withLOption=*/false);
+ else
+ driver->addFile(saver.save(config->sysroot + "/" + s.substr(1)),
+ /*withLOption=*/false);
+ } else if (s.startswith("-l")) {
+ driver->addLibrary(s.substr(2));
+ } else if (sys::fs::exists(s)) {
+ driver->addFile(s, /*withLOption=*/false);
+ } else {
+ if (Optional<std::string> path = findFromSearchPaths(s))
+ driver->addFile(saver.save(*path), /*withLOption=*/true);
+ else
+ setError("unable to find " + s);
+ }
+}
+
+void ScriptParser::readAsNeeded() {
+ expect("(");
+ bool orig = config->asNeeded;
+ config->asNeeded = true;
+ while (!errorCount() && !consume(")"))
+ addFile(unquote(next()));
+ config->asNeeded = orig;
+}
+
+void ScriptParser::readEntry() {
+ // -e <symbol> takes predecence over ENTRY(<symbol>).
+ expect("(");
+ StringRef tok = next();
+ if (config->entry.empty())
+ config->entry = tok;
+ expect(")");
+}
+
+void ScriptParser::readExtern() {
+ expect("(");
+ while (!errorCount() && !consume(")"))
+ config->undefined.push_back(unquote(next()));
+}
+
+void ScriptParser::readGroup() {
+ bool orig = InputFile::isInGroup;
+ InputFile::isInGroup = true;
+ readInput();
+ InputFile::isInGroup = orig;
+ if (!orig)
+ ++InputFile::nextGroupId;
+}
+
+void ScriptParser::readInclude() {
+ StringRef tok = unquote(next());
+
+ if (!seen.insert(tok).second) {
+ setError("there is a cycle in linker script INCLUDEs");
+ return;
+ }
+
+ if (Optional<std::string> path = searchScript(tok)) {
+ if (Optional<MemoryBufferRef> mb = readFile(*path))
+ tokenize(*mb);
+ return;
+ }
+ setError("cannot find linker script " + tok);
+}
+
+void ScriptParser::readInput() {
+ expect("(");
+ while (!errorCount() && !consume(")")) {
+ if (consume("AS_NEEDED"))
+ readAsNeeded();
+ else
+ addFile(unquote(next()));
+ }
+}
+
+void ScriptParser::readOutput() {
+ // -o <file> takes predecence over OUTPUT(<file>).
+ expect("(");
+ StringRef tok = next();
+ if (config->outputFile.empty())
+ config->outputFile = unquote(tok);
+ expect(")");
+}
+
+void ScriptParser::readOutputArch() {
+ // OUTPUT_ARCH is ignored for now.
+ expect("(");
+ while (!errorCount() && !consume(")"))
+ skip();
+}
+
+static std::pair<ELFKind, uint16_t> parseBfdName(StringRef s) {
+ return StringSwitch<std::pair<ELFKind, uint16_t>>(s)
+ .Case("elf32-i386", {ELF32LEKind, EM_386})
+ .Case("elf32-iamcu", {ELF32LEKind, EM_IAMCU})
+ .Case("elf32-littlearm", {ELF32LEKind, EM_ARM})
+ .Case("elf32-x86-64", {ELF32LEKind, EM_X86_64})
+ .Case("elf64-aarch64", {ELF64LEKind, EM_AARCH64})
+ .Case("elf64-littleaarch64", {ELF64LEKind, EM_AARCH64})
+ .Case("elf32-powerpc", {ELF32BEKind, EM_PPC})
+ .Case("elf64-powerpc", {ELF64BEKind, EM_PPC64})
+ .Case("elf64-powerpcle", {ELF64LEKind, EM_PPC64})
+ .Case("elf64-x86-64", {ELF64LEKind, EM_X86_64})
+ .Cases("elf32-tradbigmips", "elf32-bigmips", {ELF32BEKind, EM_MIPS})
+ .Case("elf32-ntradbigmips", {ELF32BEKind, EM_MIPS})
+ .Case("elf32-tradlittlemips", {ELF32LEKind, EM_MIPS})
+ .Case("elf32-ntradlittlemips", {ELF32LEKind, EM_MIPS})
+ .Case("elf64-tradbigmips", {ELF64BEKind, EM_MIPS})
+ .Case("elf64-tradlittlemips", {ELF64LEKind, EM_MIPS})
+ .Case("elf32-littleriscv", {ELF32LEKind, EM_RISCV})
+ .Case("elf64-littleriscv", {ELF64LEKind, EM_RISCV})
+ .Default({ELFNoneKind, EM_NONE});
+}
+
+// Parse OUTPUT_FORMAT(bfdname) or OUTPUT_FORMAT(bfdname, big, little).
+// Currently we ignore big and little parameters.
+void ScriptParser::readOutputFormat() {
+ expect("(");
+
+ StringRef name = unquote(next());
+ StringRef s = name;
+ if (s.consume_back("-freebsd"))
+ config->osabi = ELFOSABI_FREEBSD;
+
+ std::tie(config->ekind, config->emachine) = parseBfdName(s);
+ if (config->emachine == EM_NONE)
+ setError("unknown output format name: " + name);
+ if (s == "elf32-ntradlittlemips" || s == "elf32-ntradbigmips")
+ config->mipsN32Abi = true;
+
+ if (consume(")"))
+ return;
+ expect(",");
+ skip();
+ expect(",");
+ skip();
+ expect(")");
+}
+
+void ScriptParser::readPhdrs() {
+ expect("{");
+
+ while (!errorCount() && !consume("}")) {
+ PhdrsCommand cmd;
+ cmd.name = next();
+ cmd.type = readPhdrType();
+
+ while (!errorCount() && !consume(";")) {
+ if (consume("FILEHDR"))
+ cmd.hasFilehdr = true;
+ else if (consume("PHDRS"))
+ cmd.hasPhdrs = true;
+ else if (consume("AT"))
+ cmd.lmaExpr = readParenExpr();
+ else if (consume("FLAGS"))
+ cmd.flags = readParenExpr()().getValue();
+ else
+ setError("unexpected header attribute: " + next());
+ }
+
+ script->phdrsCommands.push_back(cmd);
+ }
+}
+
+void ScriptParser::readRegionAlias() {
+ expect("(");
+ StringRef alias = unquote(next());
+ expect(",");
+ StringRef name = next();
+ expect(")");
+
+ if (script->memoryRegions.count(alias))
+ setError("redefinition of memory region '" + alias + "'");
+ if (!script->memoryRegions.count(name))
+ setError("memory region '" + name + "' is not defined");
+ script->memoryRegions.insert({alias, script->memoryRegions[name]});
+}
+
+void ScriptParser::readSearchDir() {
+ expect("(");
+ StringRef tok = next();
+ if (!config->nostdlib)
+ config->searchPaths.push_back(unquote(tok));
+ expect(")");
+}
+
+// This reads an overlay description. Overlays are used to describe output
+// sections that use the same virtual memory range and normally would trigger
+// linker's sections sanity check failures.
+// https://sourceware.org/binutils/docs/ld/Overlay-Description.html#Overlay-Description
+std::vector<BaseCommand *> ScriptParser::readOverlay() {
+ // VA and LMA expressions are optional, though for simplicity of
+ // implementation we assume they are not. That is what OVERLAY was designed
+ // for first of all: to allow sections with overlapping VAs at different LMAs.
+ Expr addrExpr = readExpr();
+ expect(":");
+ expect("AT");
+ Expr lmaExpr = readParenExpr();
+ expect("{");
+
+ std::vector<BaseCommand *> v;
+ OutputSection *prev = nullptr;
+ while (!errorCount() && !consume("}")) {
+ // VA is the same for all sections. The LMAs are consecutive in memory
+ // starting from the base load address specified.
+ OutputSection *os = readOverlaySectionDescription();
+ os->addrExpr = addrExpr;
+ if (prev)
+ os->lmaExpr = [=] { return prev->getLMA() + prev->size; };
+ else
+ os->lmaExpr = lmaExpr;
+ v.push_back(os);
+ prev = os;
+ }
+
+ // According to the specification, at the end of the overlay, the location
+ // counter should be equal to the overlay base address plus size of the
+ // largest section seen in the overlay.
+ // Here we want to create the Dot assignment command to achieve that.
+ Expr moveDot = [=] {
+ uint64_t max = 0;
+ for (BaseCommand *cmd : v)
+ max = std::max(max, cast<OutputSection>(cmd)->size);
+ return addrExpr().getValue() + max;
+ };
+ v.push_back(make<SymbolAssignment>(".", moveDot, getCurrentLocation()));
+ return v;
+}
+
+void ScriptParser::readSections() {
+ script->hasSectionsCommand = true;
+
+ // -no-rosegment is used to avoid placing read only non-executable sections in
+ // their own segment. We do the same if SECTIONS command is present in linker
+ // script. See comment for computeFlags().
+ config->singleRoRx = true;
+
+ expect("{");
+ std::vector<BaseCommand *> v;
+ while (!errorCount() && !consume("}")) {
+ StringRef tok = next();
+ if (tok == "OVERLAY") {
+ for (BaseCommand *cmd : readOverlay())
+ v.push_back(cmd);
+ continue;
+ } else if (tok == "INCLUDE") {
+ readInclude();
+ continue;
+ }
+
+ if (BaseCommand *cmd = readAssignment(tok))
+ v.push_back(cmd);
+ else
+ v.push_back(readOutputSectionDescription(tok));
+ }
+
+ if (!atEOF() && consume("INSERT")) {
+ std::vector<BaseCommand *> *dest = nullptr;
+ if (consume("AFTER"))
+ dest = &script->insertAfterCommands[next()];
+ else if (consume("BEFORE"))
+ dest = &script->insertBeforeCommands[next()];
+ else
+ setError("expected AFTER/BEFORE, but got '" + next() + "'");
+ if (dest)
+ dest->insert(dest->end(), v.begin(), v.end());
+ return;
+ }
+
+ script->sectionCommands.insert(script->sectionCommands.end(), v.begin(),
+ v.end());
+}
+
+void ScriptParser::readTarget() {
+ // TARGET(foo) is an alias for "--format foo". Unlike GNU linkers,
+ // we accept only a limited set of BFD names (i.e. "elf" or "binary")
+ // for --format. We recognize only /^elf/ and "binary" in the linker
+ // script as well.
+ expect("(");
+ StringRef tok = next();
+ expect(")");
+
+ if (tok.startswith("elf"))
+ config->formatBinary = false;
+ else if (tok == "binary")
+ config->formatBinary = true;
+ else
+ setError("unknown target: " + tok);
+}
+
+static int precedence(StringRef op) {
+ return StringSwitch<int>(op)
+ .Cases("*", "/", "%", 8)
+ .Cases("+", "-", 7)
+ .Cases("<<", ">>", 6)
+ .Cases("<", "<=", ">", ">=", "==", "!=", 5)
+ .Case("&", 4)
+ .Case("|", 3)
+ .Case("&&", 2)
+ .Case("||", 1)
+ .Default(-1);
+}
+
+StringMatcher ScriptParser::readFilePatterns() {
+ std::vector<StringRef> v;
+ while (!errorCount() && !consume(")"))
+ v.push_back(next());
+ return StringMatcher(v);
+}
+
+SortSectionPolicy ScriptParser::readSortKind() {
+ if (consume("SORT") || consume("SORT_BY_NAME"))
+ return SortSectionPolicy::Name;
+ if (consume("SORT_BY_ALIGNMENT"))
+ return SortSectionPolicy::Alignment;
+ if (consume("SORT_BY_INIT_PRIORITY"))
+ return SortSectionPolicy::Priority;
+ if (consume("SORT_NONE"))
+ return SortSectionPolicy::None;
+ return SortSectionPolicy::Default;
+}
+
+// Reads SECTIONS command contents in the following form:
+//
+// <contents> ::= <elem>*
+// <elem> ::= <exclude>? <glob-pattern>
+// <exclude> ::= "EXCLUDE_FILE" "(" <glob-pattern>+ ")"
+//
+// For example,
+//
+// *(.foo EXCLUDE_FILE (a.o) .bar EXCLUDE_FILE (b.o) .baz)
+//
+// is parsed as ".foo", ".bar" with "a.o", and ".baz" with "b.o".
+// The semantics of that is section .foo in any file, section .bar in
+// any file but a.o, and section .baz in any file but b.o.
+std::vector<SectionPattern> ScriptParser::readInputSectionsList() {
+ std::vector<SectionPattern> ret;
+ while (!errorCount() && peek() != ")") {
+ StringMatcher excludeFilePat;
+ if (consume("EXCLUDE_FILE")) {
+ expect("(");
+ excludeFilePat = readFilePatterns();
+ }
+
+ std::vector<StringRef> v;
+ while (!errorCount() && peek() != ")" && peek() != "EXCLUDE_FILE")
+ v.push_back(unquote(next()));
+
+ if (!v.empty())
+ ret.push_back({std::move(excludeFilePat), StringMatcher(v)});
+ else
+ setError("section pattern is expected");
+ }
+ return ret;
+}
+
+// Reads contents of "SECTIONS" directive. That directive contains a
+// list of glob patterns for input sections. The grammar is as follows.
+//
+// <patterns> ::= <section-list>
+// | <sort> "(" <section-list> ")"
+// | <sort> "(" <sort> "(" <section-list> ")" ")"
+//
+// <sort> ::= "SORT" | "SORT_BY_NAME" | "SORT_BY_ALIGNMENT"
+// | "SORT_BY_INIT_PRIORITY" | "SORT_NONE"
+//
+// <section-list> is parsed by readInputSectionsList().
+InputSectionDescription *
+ScriptParser::readInputSectionRules(StringRef filePattern) {
+ auto *cmd = make<InputSectionDescription>(filePattern);
+ expect("(");
+
+ while (!errorCount() && !consume(")")) {
+ SortSectionPolicy outer = readSortKind();
+ SortSectionPolicy inner = SortSectionPolicy::Default;
+ std::vector<SectionPattern> v;
+ if (outer != SortSectionPolicy::Default) {
+ expect("(");
+ inner = readSortKind();
+ if (inner != SortSectionPolicy::Default) {
+ expect("(");
+ v = readInputSectionsList();
+ expect(")");
+ } else {
+ v = readInputSectionsList();
+ }
+ expect(")");
+ } else {
+ v = readInputSectionsList();
+ }
+
+ for (SectionPattern &pat : v) {
+ pat.sortInner = inner;
+ pat.sortOuter = outer;
+ }
+
+ std::move(v.begin(), v.end(), std::back_inserter(cmd->sectionPatterns));
+ }
+ return cmd;
+}
+
+InputSectionDescription *
+ScriptParser::readInputSectionDescription(StringRef tok) {
+ // Input section wildcard can be surrounded by KEEP.
+ // https://sourceware.org/binutils/docs/ld/Input-Section-Keep.html#Input-Section-Keep
+ if (tok == "KEEP") {
+ expect("(");
+ StringRef filePattern = next();
+ InputSectionDescription *cmd = readInputSectionRules(filePattern);
+ expect(")");
+ script->keptSections.push_back(cmd);
+ return cmd;
+ }
+ return readInputSectionRules(tok);
+}
+
+void ScriptParser::readSort() {
+ expect("(");
+ expect("CONSTRUCTORS");
+ expect(")");
+}
+
+Expr ScriptParser::readAssert() {
+ expect("(");
+ Expr e = readExpr();
+ expect(",");
+ StringRef msg = unquote(next());
+ expect(")");
+
+ return [=] {
+ if (!e().getValue())
+ error(msg);
+ return script->getDot();
+ };
+}
+
+// Tries to read the special directive for an output section definition which
+// can be one of following: "(NOLOAD)", "(COPY)", "(INFO)" or "(OVERLAY)".
+// Tok1 and Tok2 are next 2 tokens peeked. See comment for readSectionAddressType below.
+bool ScriptParser::readSectionDirective(OutputSection *cmd, StringRef tok1, StringRef tok2) {
+ if (tok1 != "(")
+ return false;
+ if (tok2 != "NOLOAD" && tok2 != "COPY" && tok2 != "INFO" && tok2 != "OVERLAY")
+ return false;
+
+ expect("(");
+ if (consume("NOLOAD")) {
+ cmd->noload = true;
+ } else {
+ skip(); // This is "COPY", "INFO" or "OVERLAY".
+ cmd->nonAlloc = true;
+ }
+ expect(")");
+ return true;
+}
+
+// Reads an expression and/or the special directive for an output
+// section definition. Directive is one of following: "(NOLOAD)",
+// "(COPY)", "(INFO)" or "(OVERLAY)".
+//
+// An output section name can be followed by an address expression
+// and/or directive. This grammar is not LL(1) because "(" can be
+// interpreted as either the beginning of some expression or beginning
+// of directive.
+//
+// https://sourceware.org/binutils/docs/ld/Output-Section-Address.html
+// https://sourceware.org/binutils/docs/ld/Output-Section-Type.html
+void ScriptParser::readSectionAddressType(OutputSection *cmd) {
+ if (readSectionDirective(cmd, peek(), peek2()))
+ return;
+
+ cmd->addrExpr = readExpr();
+ if (peek() == "(" && !readSectionDirective(cmd, "(", peek2()))
+ setError("unknown section directive: " + peek2());
+}
+
+static Expr checkAlignment(Expr e, std::string &loc) {
+ return [=] {
+ uint64_t alignment = std::max((uint64_t)1, e().getValue());
+ if (!isPowerOf2_64(alignment)) {
+ error(loc + ": alignment must be power of 2");
+ return (uint64_t)1; // Return a dummy value.
+ }
+ return alignment;
+ };
+}
+
+OutputSection *ScriptParser::readOverlaySectionDescription() {
+ OutputSection *cmd =
+ script->createOutputSection(next(), getCurrentLocation());
+ cmd->inOverlay = true;
+ expect("{");
+ while (!errorCount() && !consume("}"))
+ cmd->sectionCommands.push_back(readInputSectionRules(next()));
+ cmd->phdrs = readOutputSectionPhdrs();
+ return cmd;
+}
+
+OutputSection *ScriptParser::readOutputSectionDescription(StringRef outSec) {
+ OutputSection *cmd =
+ script->createOutputSection(outSec, getCurrentLocation());
+
+ size_t symbolsReferenced = script->referencedSymbols.size();
+
+ if (peek() != ":")
+ readSectionAddressType(cmd);
+ expect(":");
+
+ std::string location = getCurrentLocation();
+ if (consume("AT"))
+ cmd->lmaExpr = readParenExpr();
+ if (consume("ALIGN"))
+ cmd->alignExpr = checkAlignment(readParenExpr(), location);
+ if (consume("SUBALIGN"))
+ cmd->subalignExpr = checkAlignment(readParenExpr(), location);
+
+ // Parse constraints.
+ if (consume("ONLY_IF_RO"))
+ cmd->constraint = ConstraintKind::ReadOnly;
+ if (consume("ONLY_IF_RW"))
+ cmd->constraint = ConstraintKind::ReadWrite;
+ expect("{");
+
+ while (!errorCount() && !consume("}")) {
+ StringRef tok = next();
+ if (tok == ";") {
+ // Empty commands are allowed. Do nothing here.
+ } else if (SymbolAssignment *assign = readAssignment(tok)) {
+ cmd->sectionCommands.push_back(assign);
+ } else if (ByteCommand *data = readByteCommand(tok)) {
+ cmd->sectionCommands.push_back(data);
+ } else if (tok == "CONSTRUCTORS") {
+ // CONSTRUCTORS is a keyword to make the linker recognize C++ ctors/dtors
+ // by name. This is for very old file formats such as ECOFF/XCOFF.
+ // For ELF, we should ignore.
+ } else if (tok == "FILL") {
+ // We handle the FILL command as an alias for =fillexp section attribute,
+ // which is different from what GNU linkers do.
+ // https://sourceware.org/binutils/docs/ld/Output-Section-Data.html
+ expect("(");
+ cmd->filler = readFill();
+ expect(")");
+ } else if (tok == "SORT") {
+ readSort();
+ } else if (tok == "INCLUDE") {
+ readInclude();
+ } else if (peek() == "(") {
+ cmd->sectionCommands.push_back(readInputSectionDescription(tok));
+ } else {
+ // We have a file name and no input sections description. It is not a
+ // commonly used syntax, but still acceptable. In that case, all sections
+ // from the file will be included.
+ auto *isd = make<InputSectionDescription>(tok);
+ isd->sectionPatterns.push_back({{}, StringMatcher({"*"})});
+ cmd->sectionCommands.push_back(isd);
+ }
+ }
+
+ if (consume(">"))
+ cmd->memoryRegionName = next();
+
+ if (consume("AT")) {
+ expect(">");
+ cmd->lmaRegionName = next();
+ }
+
+ if (cmd->lmaExpr && !cmd->lmaRegionName.empty())
+ error("section can't have both LMA and a load region");
+
+ cmd->phdrs = readOutputSectionPhdrs();
+
+ if (peek() == "=" || peek().startswith("=")) {
+ inExpr = true;
+ consume("=");
+ cmd->filler = readFill();
+ inExpr = false;
+ }
+
+ // Consume optional comma following output section command.
+ consume(",");
+
+ if (script->referencedSymbols.size() > symbolsReferenced)
+ cmd->expressionsUseSymbols = true;
+ return cmd;
+}
+
+// Reads a `=<fillexp>` expression and returns its value as a big-endian number.
+// https://sourceware.org/binutils/docs/ld/Output-Section-Fill.html
+// We do not support using symbols in such expressions.
+//
+// When reading a hexstring, ld.bfd handles it as a blob of arbitrary
+// size, while ld.gold always handles it as a 32-bit big-endian number.
+// We are compatible with ld.gold because it's easier to implement.
+std::array<uint8_t, 4> ScriptParser::readFill() {
+ uint64_t value = readExpr()().val;
+ if (value > UINT32_MAX)
+ setError("filler expression result does not fit 32-bit: 0x" +
+ Twine::utohexstr(value));
+
+ std::array<uint8_t, 4> buf;
+ write32be(buf.data(), (uint32_t)value);
+ return buf;
+}
+
+SymbolAssignment *ScriptParser::readProvideHidden(bool provide, bool hidden) {
+ expect("(");
+ SymbolAssignment *cmd = readSymbolAssignment(next());
+ cmd->provide = provide;
+ cmd->hidden = hidden;
+ expect(")");
+ return cmd;
+}
+
+SymbolAssignment *ScriptParser::readAssignment(StringRef tok) {
+ // Assert expression returns Dot, so this is equal to ".=."
+ if (tok == "ASSERT")
+ return make<SymbolAssignment>(".", readAssert(), getCurrentLocation());
+
+ size_t oldPos = pos;
+ SymbolAssignment *cmd = nullptr;
+ if (peek() == "=" || peek() == "+=")
+ cmd = readSymbolAssignment(tok);
+ else if (tok == "PROVIDE")
+ cmd = readProvideHidden(true, false);
+ else if (tok == "HIDDEN")
+ cmd = readProvideHidden(false, true);
+ else if (tok == "PROVIDE_HIDDEN")
+ cmd = readProvideHidden(true, true);
+
+ if (cmd) {
+ cmd->commandString =
+ tok.str() + " " +
+ llvm::join(tokens.begin() + oldPos, tokens.begin() + pos, " ");
+ expect(";");
+ }
+ return cmd;
+}
+
+SymbolAssignment *ScriptParser::readSymbolAssignment(StringRef name) {
+ StringRef op = next();
+ assert(op == "=" || op == "+=");
+ Expr e = readExpr();
+ if (op == "+=") {
+ std::string loc = getCurrentLocation();
+ e = [=] { return add(script->getSymbolValue(name, loc), e()); };
+ }
+ return make<SymbolAssignment>(name, e, getCurrentLocation());
+}
+
+// This is an operator-precedence parser to parse a linker
+// script expression.
+Expr ScriptParser::readExpr() {
+ // Our lexer is context-aware. Set the in-expression bit so that
+ // they apply different tokenization rules.
+ bool orig = inExpr;
+ inExpr = true;
+ Expr e = readExpr1(readPrimary(), 0);
+ inExpr = orig;
+ return e;
+}
+
+Expr ScriptParser::combine(StringRef op, Expr l, Expr r) {
+ if (op == "+")
+ return [=] { return add(l(), r()); };
+ if (op == "-")
+ return [=] { return sub(l(), r()); };
+ if (op == "*")
+ return [=] { return l().getValue() * r().getValue(); };
+ if (op == "/") {
+ std::string loc = getCurrentLocation();
+ return [=]() -> uint64_t {
+ if (uint64_t rv = r().getValue())
+ return l().getValue() / rv;
+ error(loc + ": division by zero");
+ return 0;
+ };
+ }
+ if (op == "%") {
+ std::string loc = getCurrentLocation();
+ return [=]() -> uint64_t {
+ if (uint64_t rv = r().getValue())
+ return l().getValue() % rv;
+ error(loc + ": modulo by zero");
+ return 0;
+ };
+ }
+ if (op == "<<")
+ return [=] { return l().getValue() << r().getValue(); };
+ if (op == ">>")
+ return [=] { return l().getValue() >> r().getValue(); };
+ if (op == "<")
+ return [=] { return l().getValue() < r().getValue(); };
+ if (op == ">")
+ return [=] { return l().getValue() > r().getValue(); };
+ if (op == ">=")
+ return [=] { return l().getValue() >= r().getValue(); };
+ if (op == "<=")
+ return [=] { return l().getValue() <= r().getValue(); };
+ if (op == "==")
+ return [=] { return l().getValue() == r().getValue(); };
+ if (op == "!=")
+ return [=] { return l().getValue() != r().getValue(); };
+ if (op == "||")
+ return [=] { return l().getValue() || r().getValue(); };
+ if (op == "&&")
+ return [=] { return l().getValue() && r().getValue(); };
+ if (op == "&")
+ return [=] { return bitAnd(l(), r()); };
+ if (op == "|")
+ return [=] { return bitOr(l(), r()); };
+ llvm_unreachable("invalid operator");
+}
+
+// This is a part of the operator-precedence parser. This function
+// assumes that the remaining token stream starts with an operator.
+Expr ScriptParser::readExpr1(Expr lhs, int minPrec) {
+ while (!atEOF() && !errorCount()) {
+ // Read an operator and an expression.
+ if (consume("?"))
+ return readTernary(lhs);
+ StringRef op1 = peek();
+ if (precedence(op1) < minPrec)
+ break;
+ skip();
+ Expr rhs = readPrimary();
+
+ // Evaluate the remaining part of the expression first if the
+ // next operator has greater precedence than the previous one.
+ // For example, if we have read "+" and "3", and if the next
+ // operator is "*", then we'll evaluate 3 * ... part first.
+ while (!atEOF()) {
+ StringRef op2 = peek();
+ if (precedence(op2) <= precedence(op1))
+ break;
+ rhs = readExpr1(rhs, precedence(op2));
+ }
+
+ lhs = combine(op1, lhs, rhs);
+ }
+ return lhs;
+}
+
+Expr ScriptParser::getPageSize() {
+ std::string location = getCurrentLocation();
+ return [=]() -> uint64_t {
+ if (target)
+ return config->commonPageSize;
+ error(location + ": unable to calculate page size");
+ return 4096; // Return a dummy value.
+ };
+}
+
+Expr ScriptParser::readConstant() {
+ StringRef s = readParenLiteral();
+ if (s == "COMMONPAGESIZE")
+ return getPageSize();
+ if (s == "MAXPAGESIZE")
+ return [] { return config->maxPageSize; };
+ setError("unknown constant: " + s);
+ return [] { return 0; };
+}
+
+// Parses Tok as an integer. It recognizes hexadecimal (prefixed with
+// "0x" or suffixed with "H") and decimal numbers. Decimal numbers may
+// have "K" (Ki) or "M" (Mi) suffixes.
+static Optional<uint64_t> parseInt(StringRef tok) {
+ // Hexadecimal
+ uint64_t val;
+ if (tok.startswith_lower("0x")) {
+ if (!to_integer(tok.substr(2), val, 16))
+ return None;
+ return val;
+ }
+ if (tok.endswith_lower("H")) {
+ if (!to_integer(tok.drop_back(), val, 16))
+ return None;
+ return val;
+ }
+
+ // Decimal
+ if (tok.endswith_lower("K")) {
+ if (!to_integer(tok.drop_back(), val, 10))
+ return None;
+ return val * 1024;
+ }
+ if (tok.endswith_lower("M")) {
+ if (!to_integer(tok.drop_back(), val, 10))
+ return None;
+ return val * 1024 * 1024;
+ }
+ if (!to_integer(tok, val, 10))
+ return None;
+ return val;
+}
+
+ByteCommand *ScriptParser::readByteCommand(StringRef tok) {
+ int size = StringSwitch<int>(tok)
+ .Case("BYTE", 1)
+ .Case("SHORT", 2)
+ .Case("LONG", 4)
+ .Case("QUAD", 8)
+ .Default(-1);
+ if (size == -1)
+ return nullptr;
+
+ size_t oldPos = pos;
+ Expr e = readParenExpr();
+ std::string commandString =
+ tok.str() + " " +
+ llvm::join(tokens.begin() + oldPos, tokens.begin() + pos, " ");
+ return make<ByteCommand>(e, size, commandString);
+}
+
+StringRef ScriptParser::readParenLiteral() {
+ expect("(");
+ bool orig = inExpr;
+ inExpr = false;
+ StringRef tok = next();
+ inExpr = orig;
+ expect(")");
+ return tok;
+}
+
+static void checkIfExists(OutputSection *cmd, StringRef location) {
+ if (cmd->location.empty() && script->errorOnMissingSection)
+ error(location + ": undefined section " + cmd->name);
+}
+
+Expr ScriptParser::readPrimary() {
+ if (peek() == "(")
+ return readParenExpr();
+
+ if (consume("~")) {
+ Expr e = readPrimary();
+ return [=] { return ~e().getValue(); };
+ }
+ if (consume("!")) {
+ Expr e = readPrimary();
+ return [=] { return !e().getValue(); };
+ }
+ if (consume("-")) {
+ Expr e = readPrimary();
+ return [=] { return -e().getValue(); };
+ }
+
+ StringRef tok = next();
+ std::string location = getCurrentLocation();
+
+ // Built-in functions are parsed here.
+ // https://sourceware.org/binutils/docs/ld/Builtin-Functions.html.
+ if (tok == "ABSOLUTE") {
+ Expr inner = readParenExpr();
+ return [=] {
+ ExprValue i = inner();
+ i.forceAbsolute = true;
+ return i;
+ };
+ }
+ if (tok == "ADDR") {
+ StringRef name = readParenLiteral();
+ OutputSection *sec = script->getOrCreateOutputSection(name);
+ sec->usedInExpression = true;
+ return [=]() -> ExprValue {
+ checkIfExists(sec, location);
+ return {sec, false, 0, location};
+ };
+ }
+ if (tok == "ALIGN") {
+ expect("(");
+ Expr e = readExpr();
+ if (consume(")")) {
+ e = checkAlignment(e, location);
+ return [=] { return alignTo(script->getDot(), e().getValue()); };
+ }
+ expect(",");
+ Expr e2 = checkAlignment(readExpr(), location);
+ expect(")");
+ return [=] {
+ ExprValue v = e();
+ v.alignment = e2().getValue();
+ return v;
+ };
+ }
+ if (tok == "ALIGNOF") {
+ StringRef name = readParenLiteral();
+ OutputSection *cmd = script->getOrCreateOutputSection(name);
+ return [=] {
+ checkIfExists(cmd, location);
+ return cmd->alignment;
+ };
+ }
+ if (tok == "ASSERT")
+ return readAssert();
+ if (tok == "CONSTANT")
+ return readConstant();
+ if (tok == "DATA_SEGMENT_ALIGN") {
+ expect("(");
+ Expr e = readExpr();
+ expect(",");
+ readExpr();
+ expect(")");
+ return [=] {
+ return alignTo(script->getDot(), std::max((uint64_t)1, e().getValue()));
+ };
+ }
+ if (tok == "DATA_SEGMENT_END") {
+ expect("(");
+ expect(".");
+ expect(")");
+ return [] { return script->getDot(); };
+ }
+ if (tok == "DATA_SEGMENT_RELRO_END") {
+ // GNU linkers implements more complicated logic to handle
+ // DATA_SEGMENT_RELRO_END. We instead ignore the arguments and
+ // just align to the next page boundary for simplicity.
+ expect("(");
+ readExpr();
+ expect(",");
+ readExpr();
+ expect(")");
+ Expr e = getPageSize();
+ return [=] { return alignTo(script->getDot(), e().getValue()); };
+ }
+ if (tok == "DEFINED") {
+ StringRef name = readParenLiteral();
+ return [=] { return symtab->find(name) ? 1 : 0; };
+ }
+ if (tok == "LENGTH") {
+ StringRef name = readParenLiteral();
+ if (script->memoryRegions.count(name) == 0) {
+ setError("memory region not defined: " + name);
+ return [] { return 0; };
+ }
+ return [=] { return script->memoryRegions[name]->length; };
+ }
+ if (tok == "LOADADDR") {
+ StringRef name = readParenLiteral();
+ OutputSection *cmd = script->getOrCreateOutputSection(name);
+ cmd->usedInExpression = true;
+ return [=] {
+ checkIfExists(cmd, location);
+ return cmd->getLMA();
+ };
+ }
+ if (tok == "MAX" || tok == "MIN") {
+ expect("(");
+ Expr a = readExpr();
+ expect(",");
+ Expr b = readExpr();
+ expect(")");
+ if (tok == "MIN")
+ return [=] { return std::min(a().getValue(), b().getValue()); };
+ return [=] { return std::max(a().getValue(), b().getValue()); };
+ }
+ if (tok == "ORIGIN") {
+ StringRef name = readParenLiteral();
+ if (script->memoryRegions.count(name) == 0) {
+ setError("memory region not defined: " + name);
+ return [] { return 0; };
+ }
+ return [=] { return script->memoryRegions[name]->origin; };
+ }
+ if (tok == "SEGMENT_START") {
+ expect("(");
+ skip();
+ expect(",");
+ Expr e = readExpr();
+ expect(")");
+ return [=] { return e(); };
+ }
+ if (tok == "SIZEOF") {
+ StringRef name = readParenLiteral();
+ OutputSection *cmd = script->getOrCreateOutputSection(name);
+ // Linker script does not create an output section if its content is empty.
+ // We want to allow SIZEOF(.foo) where .foo is a section which happened to
+ // be empty.
+ return [=] { return cmd->size; };
+ }
+ if (tok == "SIZEOF_HEADERS")
+ return [=] { return elf::getHeaderSize(); };
+
+ // Tok is the dot.
+ if (tok == ".")
+ return [=] { return script->getSymbolValue(tok, location); };
+
+ // Tok is a literal number.
+ if (Optional<uint64_t> val = parseInt(tok))
+ return [=] { return *val; };
+
+ // Tok is a symbol name.
+ if (!isValidCIdentifier(tok))
+ setError("malformed number: " + tok);
+ script->referencedSymbols.push_back(tok);
+ return [=] { return script->getSymbolValue(tok, location); };
+}
+
+Expr ScriptParser::readTernary(Expr cond) {
+ Expr l = readExpr();
+ expect(":");
+ Expr r = readExpr();
+ return [=] { return cond().getValue() ? l() : r(); };
+}
+
+Expr ScriptParser::readParenExpr() {
+ expect("(");
+ Expr e = readExpr();
+ expect(")");
+ return e;
+}
+
+std::vector<StringRef> ScriptParser::readOutputSectionPhdrs() {
+ std::vector<StringRef> phdrs;
+ while (!errorCount() && peek().startswith(":")) {
+ StringRef tok = next();
+ phdrs.push_back((tok.size() == 1) ? next() : tok.substr(1));
+ }
+ return phdrs;
+}
+
+// Read a program header type name. The next token must be a
+// name of a program header type or a constant (e.g. "0x3").
+unsigned ScriptParser::readPhdrType() {
+ StringRef tok = next();
+ if (Optional<uint64_t> val = parseInt(tok))
+ return *val;
+
+ unsigned ret = StringSwitch<unsigned>(tok)
+ .Case("PT_NULL", PT_NULL)
+ .Case("PT_LOAD", PT_LOAD)
+ .Case("PT_DYNAMIC", PT_DYNAMIC)
+ .Case("PT_INTERP", PT_INTERP)
+ .Case("PT_NOTE", PT_NOTE)
+ .Case("PT_SHLIB", PT_SHLIB)
+ .Case("PT_PHDR", PT_PHDR)
+ .Case("PT_TLS", PT_TLS)
+ .Case("PT_GNU_EH_FRAME", PT_GNU_EH_FRAME)
+ .Case("PT_GNU_STACK", PT_GNU_STACK)
+ .Case("PT_GNU_RELRO", PT_GNU_RELRO)
+ .Case("PT_OPENBSD_RANDOMIZE", PT_OPENBSD_RANDOMIZE)
+ .Case("PT_OPENBSD_WXNEEDED", PT_OPENBSD_WXNEEDED)
+ .Case("PT_OPENBSD_BOOTDATA", PT_OPENBSD_BOOTDATA)
+ .Default(-1);
+
+ if (ret == (unsigned)-1) {
+ setError("invalid program header type: " + tok);
+ return PT_NULL;
+ }
+ return ret;
+}
+
+// Reads an anonymous version declaration.
+void ScriptParser::readAnonymousDeclaration() {
+ std::vector<SymbolVersion> locals;
+ std::vector<SymbolVersion> globals;
+ std::tie(locals, globals) = readSymbols();
+
+ for (SymbolVersion v : locals) {
+ if (v.name == "*")
+ config->defaultSymbolVersion = VER_NDX_LOCAL;
+ else
+ config->versionScriptLocals.push_back(v);
+ }
+
+ for (SymbolVersion v : globals)
+ config->versionScriptGlobals.push_back(v);
+
+ expect(";");
+}
+
+// Reads a non-anonymous version definition,
+// e.g. "VerStr { global: foo; bar; local: *; };".
+void ScriptParser::readVersionDeclaration(StringRef verStr) {
+ // Read a symbol list.
+ std::vector<SymbolVersion> locals;
+ std::vector<SymbolVersion> globals;
+ std::tie(locals, globals) = readSymbols();
+
+ for (SymbolVersion v : locals) {
+ if (v.name == "*")
+ config->defaultSymbolVersion = VER_NDX_LOCAL;
+ else
+ config->versionScriptLocals.push_back(v);
+ }
+
+ // Create a new version definition and add that to the global symbols.
+ VersionDefinition ver;
+ ver.name = verStr;
+ ver.globals = globals;
+
+ // User-defined version number starts from 2 because 0 and 1 are
+ // reserved for VER_NDX_LOCAL and VER_NDX_GLOBAL, respectively.
+ ver.id = config->versionDefinitions.size() + 2;
+ config->versionDefinitions.push_back(ver);
+
+ // Each version may have a parent version. For example, "Ver2"
+ // defined as "Ver2 { global: foo; local: *; } Ver1;" has "Ver1"
+ // as a parent. This version hierarchy is, probably against your
+ // instinct, purely for hint; the runtime doesn't care about it
+ // at all. In LLD, we simply ignore it.
+ if (peek() != ";")
+ skip();
+ expect(";");
+}
+
+static bool hasWildcard(StringRef s) {
+ return s.find_first_of("?*[") != StringRef::npos;
+}
+
+// Reads a list of symbols, e.g. "{ global: foo; bar; local: *; };".
+std::pair<std::vector<SymbolVersion>, std::vector<SymbolVersion>>
+ScriptParser::readSymbols() {
+ std::vector<SymbolVersion> locals;
+ std::vector<SymbolVersion> globals;
+ std::vector<SymbolVersion> *v = &globals;
+
+ while (!errorCount()) {
+ if (consume("}"))
+ break;
+ if (consumeLabel("local")) {
+ v = &locals;
+ continue;
+ }
+ if (consumeLabel("global")) {
+ v = &globals;
+ continue;
+ }
+
+ if (consume("extern")) {
+ std::vector<SymbolVersion> ext = readVersionExtern();
+ v->insert(v->end(), ext.begin(), ext.end());
+ } else {
+ StringRef tok = next();
+ v->push_back({unquote(tok), false, hasWildcard(tok)});
+ }
+ expect(";");
+ }
+ return {locals, globals};
+}
+
+// Reads an "extern C++" directive, e.g.,
+// "extern "C++" { ns::*; "f(int, double)"; };"
+//
+// The last semicolon is optional. E.g. this is OK:
+// "extern "C++" { ns::*; "f(int, double)" };"
+std::vector<SymbolVersion> ScriptParser::readVersionExtern() {
+ StringRef tok = next();
+ bool isCXX = tok == "\"C++\"";
+ if (!isCXX && tok != "\"C\"")
+ setError("Unknown language");
+ expect("{");
+
+ std::vector<SymbolVersion> ret;
+ while (!errorCount() && peek() != "}") {
+ StringRef tok = next();
+ ret.push_back(
+ {unquote(tok), isCXX, !tok.startswith("\"") && hasWildcard(tok)});
+ if (consume("}"))
+ return ret;
+ expect(";");
+ }
+
+ expect("}");
+ return ret;
+}
+
+uint64_t ScriptParser::readMemoryAssignment(StringRef s1, StringRef s2,
+ StringRef s3) {
+ if (!consume(s1) && !consume(s2) && !consume(s3)) {
+ setError("expected one of: " + s1 + ", " + s2 + ", or " + s3);
+ return 0;
+ }
+ expect("=");
+ return readExpr()().getValue();
+}
+
+// Parse the MEMORY command as specified in:
+// https://sourceware.org/binutils/docs/ld/MEMORY.html
+//
+// MEMORY { name [(attr)] : ORIGIN = origin, LENGTH = len ... }
+void ScriptParser::readMemory() {
+ expect("{");
+ while (!errorCount() && !consume("}")) {
+ StringRef tok = next();
+ if (tok == "INCLUDE") {
+ readInclude();
+ continue;
+ }
+
+ uint32_t flags = 0;
+ uint32_t negFlags = 0;
+ if (consume("(")) {
+ std::tie(flags, negFlags) = readMemoryAttributes();
+ expect(")");
+ }
+ expect(":");
+
+ uint64_t origin = readMemoryAssignment("ORIGIN", "org", "o");
+ expect(",");
+ uint64_t length = readMemoryAssignment("LENGTH", "len", "l");
+
+ // Add the memory region to the region map.
+ MemoryRegion *mr = make<MemoryRegion>(tok, origin, length, flags, negFlags);
+ if (!script->memoryRegions.insert({tok, mr}).second)
+ setError("region '" + tok + "' already defined");
+ }
+}
+
+// This function parses the attributes used to match against section
+// flags when placing output sections in a memory region. These flags
+// are only used when an explicit memory region name is not used.
+std::pair<uint32_t, uint32_t> ScriptParser::readMemoryAttributes() {
+ uint32_t flags = 0;
+ uint32_t negFlags = 0;
+ bool invert = false;
+
+ for (char c : next().lower()) {
+ uint32_t flag = 0;
+ if (c == '!')
+ invert = !invert;
+ else if (c == 'w')
+ flag = SHF_WRITE;
+ else if (c == 'x')
+ flag = SHF_EXECINSTR;
+ else if (c == 'a')
+ flag = SHF_ALLOC;
+ else if (c != 'r')
+ setError("invalid memory region attribute");
+
+ if (invert)
+ negFlags |= flag;
+ else
+ flags |= flag;
+ }
+ return {flags, negFlags};
+}
+
+void elf::readLinkerScript(MemoryBufferRef mb) {
+ ScriptParser(mb).readLinkerScript();
+}
+
+void elf::readVersionScript(MemoryBufferRef mb) {
+ ScriptParser(mb).readVersionScript();
+}
+
+void elf::readDynamicList(MemoryBufferRef mb) {
+ ScriptParser(mb).readDynamicList();
+}
+
+void elf::readDefsym(StringRef name, MemoryBufferRef mb) {
+ ScriptParser(mb).readDefsym(name);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-09 04:20:07 +0000