271 lines
10 KiB
C++
271 lines
10 KiB
C++
//===- lib/MC/MCSectionMachO.cpp - MachO Code Section Representation ------===//
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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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#include "llvm/MC/MCSectionMachO.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/Support/raw_ostream.h"
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#include <cctype>
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using namespace llvm;
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/// SectionTypeDescriptors - These are strings that describe the various section
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/// types. This *must* be kept in order with and stay synchronized with the
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/// section type list.
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static const struct {
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StringRef AssemblerName, EnumName;
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} SectionTypeDescriptors[MachO::LAST_KNOWN_SECTION_TYPE+1] = {
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{ "regular", "S_REGULAR" }, // 0x00
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{ StringRef(), "S_ZEROFILL" }, // 0x01
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{ "cstring_literals", "S_CSTRING_LITERALS" }, // 0x02
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{ "4byte_literals", "S_4BYTE_LITERALS" }, // 0x03
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{ "8byte_literals", "S_8BYTE_LITERALS" }, // 0x04
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{ "literal_pointers", "S_LITERAL_POINTERS" }, // 0x05
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{ "non_lazy_symbol_pointers", "S_NON_LAZY_SYMBOL_POINTERS" }, // 0x06
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{ "lazy_symbol_pointers", "S_LAZY_SYMBOL_POINTERS" }, // 0x07
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{ "symbol_stubs", "S_SYMBOL_STUBS" }, // 0x08
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{ "mod_init_funcs", "S_MOD_INIT_FUNC_POINTERS" }, // 0x09
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{ "mod_term_funcs", "S_MOD_TERM_FUNC_POINTERS" }, // 0x0A
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{ "coalesced", "S_COALESCED" }, // 0x0B
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{ StringRef(), /*FIXME??*/ "S_GB_ZEROFILL" }, // 0x0C
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{ "interposing", "S_INTERPOSING" }, // 0x0D
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{ "16byte_literals", "S_16BYTE_LITERALS" }, // 0x0E
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{ StringRef(), /*FIXME??*/ "S_DTRACE_DOF" }, // 0x0F
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{ StringRef(), /*FIXME??*/ "S_LAZY_DYLIB_SYMBOL_POINTERS" }, // 0x10
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{ "thread_local_regular", "S_THREAD_LOCAL_REGULAR" }, // 0x11
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{ "thread_local_zerofill", "S_THREAD_LOCAL_ZEROFILL" }, // 0x12
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{ "thread_local_variables", "S_THREAD_LOCAL_VARIABLES" }, // 0x13
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{ "thread_local_variable_pointers",
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"S_THREAD_LOCAL_VARIABLE_POINTERS" }, // 0x14
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{ "thread_local_init_function_pointers",
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"S_THREAD_LOCAL_INIT_FUNCTION_POINTERS"}, // 0x15
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};
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/// SectionAttrDescriptors - This is an array of descriptors for section
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/// attributes. Unlike the SectionTypeDescriptors, this is not directly indexed
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/// by attribute, instead it is searched.
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static const struct {
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unsigned AttrFlag;
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StringRef AssemblerName, EnumName;
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} SectionAttrDescriptors[] = {
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#define ENTRY(ASMNAME, ENUM) \
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{ MachO::ENUM, ASMNAME, #ENUM },
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ENTRY("pure_instructions", S_ATTR_PURE_INSTRUCTIONS)
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ENTRY("no_toc", S_ATTR_NO_TOC)
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ENTRY("strip_static_syms", S_ATTR_STRIP_STATIC_SYMS)
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ENTRY("no_dead_strip", S_ATTR_NO_DEAD_STRIP)
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ENTRY("live_support", S_ATTR_LIVE_SUPPORT)
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ENTRY("self_modifying_code", S_ATTR_SELF_MODIFYING_CODE)
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ENTRY("debug", S_ATTR_DEBUG)
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ENTRY(StringRef() /*FIXME*/, S_ATTR_SOME_INSTRUCTIONS)
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ENTRY(StringRef() /*FIXME*/, S_ATTR_EXT_RELOC)
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ENTRY(StringRef() /*FIXME*/, S_ATTR_LOC_RELOC)
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#undef ENTRY
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{ 0, "none", StringRef() }, // used if section has no attributes but has a stub size
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};
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MCSectionMachO::MCSectionMachO(StringRef Segment, StringRef Section,
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unsigned TAA, unsigned reserved2, SectionKind K,
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MCSymbol *Begin)
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: MCSection(SV_MachO, K, Begin), TypeAndAttributes(TAA),
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Reserved2(reserved2) {
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assert(Segment.size() <= 16 && Section.size() <= 16 &&
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"Segment or section string too long");
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for (unsigned i = 0; i != 16; ++i) {
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if (i < Segment.size())
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SegmentName[i] = Segment[i];
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else
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SegmentName[i] = 0;
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if (i < Section.size())
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SectionName[i] = Section[i];
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else
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SectionName[i] = 0;
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}
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}
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void MCSectionMachO::PrintSwitchToSection(const MCAsmInfo &MAI,
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raw_ostream &OS,
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const MCExpr *Subsection) const {
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OS << "\t.section\t" << getSegmentName() << ',' << getSectionName();
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// Get the section type and attributes.
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unsigned TAA = getTypeAndAttributes();
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if (TAA == 0) {
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OS << '\n';
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return;
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}
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MachO::SectionType SectionType = getType();
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assert(SectionType <= MachO::LAST_KNOWN_SECTION_TYPE &&
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"Invalid SectionType specified!");
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if (!SectionTypeDescriptors[SectionType].AssemblerName.empty()) {
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OS << ',';
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OS << SectionTypeDescriptors[SectionType].AssemblerName;
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} else {
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// If we have no name for the attribute, stop here.
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OS << '\n';
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return;
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}
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// If we don't have any attributes, we're done.
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unsigned SectionAttrs = TAA & MachO::SECTION_ATTRIBUTES;
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if (SectionAttrs == 0) {
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// If we have a S_SYMBOL_STUBS size specified, print it along with 'none' as
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// the attribute specifier.
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if (Reserved2 != 0)
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OS << ",none," << Reserved2;
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OS << '\n';
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return;
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}
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// Check each attribute to see if we have it.
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char Separator = ',';
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for (unsigned i = 0;
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SectionAttrs != 0 && SectionAttrDescriptors[i].AttrFlag;
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++i) {
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// Check to see if we have this attribute.
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if ((SectionAttrDescriptors[i].AttrFlag & SectionAttrs) == 0)
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continue;
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// Yep, clear it and print it.
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SectionAttrs &= ~SectionAttrDescriptors[i].AttrFlag;
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OS << Separator;
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if (!SectionAttrDescriptors[i].AssemblerName.empty())
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OS << SectionAttrDescriptors[i].AssemblerName;
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else
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OS << "<<" << SectionAttrDescriptors[i].EnumName << ">>";
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Separator = '+';
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}
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assert(SectionAttrs == 0 && "Unknown section attributes!");
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// If we have a S_SYMBOL_STUBS size specified, print it.
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if (Reserved2 != 0)
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OS << ',' << Reserved2;
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OS << '\n';
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}
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bool MCSectionMachO::UseCodeAlign() const {
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return hasAttribute(MachO::S_ATTR_PURE_INSTRUCTIONS);
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}
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bool MCSectionMachO::isVirtualSection() const {
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return (getType() == MachO::S_ZEROFILL ||
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getType() == MachO::S_GB_ZEROFILL ||
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getType() == MachO::S_THREAD_LOCAL_ZEROFILL);
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}
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/// ParseSectionSpecifier - Parse the section specifier indicated by "Spec".
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/// This is a string that can appear after a .section directive in a mach-o
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/// flavored .s file. If successful, this fills in the specified Out
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/// parameters and returns an empty string. When an invalid section
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/// specifier is present, this returns a string indicating the problem.
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std::string MCSectionMachO::ParseSectionSpecifier(StringRef Spec, // In.
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StringRef &Segment, // Out.
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StringRef &Section, // Out.
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unsigned &TAA, // Out.
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bool &TAAParsed, // Out.
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unsigned &StubSize) { // Out.
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TAAParsed = false;
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SmallVector<StringRef, 5> SplitSpec;
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Spec.split(SplitSpec, ',');
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// Remove leading and trailing whitespace.
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auto GetEmptyOrTrim = [&SplitSpec](size_t Idx) -> StringRef {
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return SplitSpec.size() > Idx ? SplitSpec[Idx].trim() : StringRef();
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};
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Segment = GetEmptyOrTrim(0);
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Section = GetEmptyOrTrim(1);
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StringRef SectionType = GetEmptyOrTrim(2);
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StringRef Attrs = GetEmptyOrTrim(3);
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StringRef StubSizeStr = GetEmptyOrTrim(4);
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// Verify that the segment is present and not too long.
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if (Segment.empty() || Segment.size() > 16)
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return "mach-o section specifier requires a segment whose length is "
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"between 1 and 16 characters";
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// Verify that the section is present and not too long.
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if (Section.empty())
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return "mach-o section specifier requires a segment and section "
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"separated by a comma";
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if (Section.size() > 16)
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return "mach-o section specifier requires a section whose length is "
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"between 1 and 16 characters";
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// If there is no comma after the section, we're done.
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TAA = 0;
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StubSize = 0;
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if (SectionType.empty())
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return "";
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// Figure out which section type it is.
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auto TypeDescriptor = std::find_if(
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std::begin(SectionTypeDescriptors), std::end(SectionTypeDescriptors),
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[&](decltype(*SectionTypeDescriptors) &Descriptor) {
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return SectionType == Descriptor.AssemblerName;
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});
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// If we didn't find the section type, reject it.
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if (TypeDescriptor == std::end(SectionTypeDescriptors))
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return "mach-o section specifier uses an unknown section type";
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// Remember the TypeID.
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TAA = TypeDescriptor - std::begin(SectionTypeDescriptors);
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TAAParsed = true;
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// If we have no comma after the section type, there are no attributes.
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if (Attrs.empty()) {
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// S_SYMBOL_STUBS always require a symbol stub size specifier.
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if (TAA == MachO::S_SYMBOL_STUBS)
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return "mach-o section specifier of type 'symbol_stubs' requires a size "
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"specifier";
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return "";
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}
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// The attribute list is a '+' separated list of attributes.
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SmallVector<StringRef, 1> SectionAttrs;
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Attrs.split(SectionAttrs, '+', /*MaxSplit=*/-1, /*KeepEmpty=*/false);
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for (StringRef &SectionAttr : SectionAttrs) {
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auto AttrDescriptorI = std::find_if(
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std::begin(SectionAttrDescriptors), std::end(SectionAttrDescriptors),
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[&](decltype(*SectionAttrDescriptors) &Descriptor) {
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return SectionAttr.trim() == Descriptor.AssemblerName;
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});
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if (AttrDescriptorI == std::end(SectionAttrDescriptors))
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return "mach-o section specifier has invalid attribute";
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TAA |= AttrDescriptorI->AttrFlag;
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}
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// Okay, we've parsed the section attributes, see if we have a stub size spec.
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if (StubSizeStr.empty()) {
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// S_SYMBOL_STUBS always require a symbol stub size specifier.
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if (TAA == MachO::S_SYMBOL_STUBS)
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return "mach-o section specifier of type 'symbol_stubs' requires a size "
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"specifier";
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return "";
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}
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// If we have a stub size spec, we must have a sectiontype of S_SYMBOL_STUBS.
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if ((TAA & MachO::SECTION_TYPE) != MachO::S_SYMBOL_STUBS)
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return "mach-o section specifier cannot have a stub size specified because "
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"it does not have type 'symbol_stubs'";
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// Convert the stub size from a string to an integer.
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if (StubSizeStr.getAsInteger(0, StubSize))
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return "mach-o section specifier has a malformed stub size";
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return "";
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}
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