From 5d0bfc8f875e3be46c44fcebf6d567480b483716 Mon Sep 17 00:00:00 2001 From: David Majnemer Date: Mon, 10 Mar 2014 00:55:07 +0000 Subject: [PATCH] MC: Cleanup MCSectionMachO::ParseSectionSpecifier Split by comma once instead of multiple times. Moving this upfront makes the rest of the code considerably simpler. No functional change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203429 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/MC/MCSectionMachO.cpp | 116 ++++++++++++++------------------------ 1 file changed, 41 insertions(+), 75 deletions(-) diff --git a/lib/MC/MCSectionMachO.cpp b/lib/MC/MCSectionMachO.cpp index 29829463c18..6f8802c9599 100644 --- a/lib/MC/MCSectionMachO.cpp +++ b/lib/MC/MCSectionMachO.cpp @@ -48,8 +48,7 @@ static const struct { /// SectionAttrDescriptors - This is an array of descriptors for section /// attributes. Unlike the SectionTypeDescriptors, this is not directly indexed -/// by attribute, instead it is searched. The last entry has an AttrFlagEnd -/// AttrFlag value. +/// by attribute, instead it is searched. static const struct { unsigned AttrFlag; const char *AssemblerName, *EnumName; @@ -68,8 +67,6 @@ ENTRY(0 /*FIXME*/, S_ATTR_EXT_RELOC) ENTRY(0 /*FIXME*/, S_ATTR_LOC_RELOC) #undef ENTRY { 0, "none", 0 }, // used if section has no attributes but has a stub size -#define AttrFlagEnd 0xffffffff // non-legal value, multiple attribute bits set - { AttrFlagEnd, 0, 0 } }; MCSectionMachO::MCSectionMachO(StringRef Segment, StringRef Section, @@ -164,14 +161,6 @@ bool MCSectionMachO::isVirtualSection() const { getType() == MachO::S_THREAD_LOCAL_ZEROFILL); } -/// StripSpaces - This removes leading and trailing spaces from the StringRef. -static void StripSpaces(StringRef &Str) { - while (!Str.empty() && isspace(static_cast(Str[0]))) - Str = Str.substr(1); - while (!Str.empty() && isspace(static_cast(Str.back()))) - Str = Str.substr(0, Str.size()-1); -} - /// ParseSectionSpecifier - Parse the section specifier indicated by "Spec". /// This is a string that can appear after a .section directive in a mach-o /// flavored .s file. If successful, this fills in the specified Out @@ -184,65 +173,57 @@ std::string MCSectionMachO::ParseSectionSpecifier(StringRef Spec, // In. bool &TAAParsed, // Out. unsigned &StubSize) { // Out. TAAParsed = false; - // Find the first comma. - std::pair Comma = Spec.split(','); - // If there is no comma, we fail. - if (Comma.second.empty()) - return "mach-o section specifier requires a segment and section " - "separated by a comma"; - - // Capture segment, remove leading and trailing whitespace. - Segment = Comma.first; - StripSpaces(Segment); + SmallVector SplitSpec; + Spec.split(SplitSpec, ","); + // Remove leading and trailing whitespace. + auto GetEmptyOrTrim = [&SplitSpec](size_t Idx) -> StringRef { + return SplitSpec.size() > Idx ? SplitSpec[Idx].trim() : StringRef(); + }; + Segment = GetEmptyOrTrim(0); + Section = GetEmptyOrTrim(1); + StringRef SectionType = GetEmptyOrTrim(2); + StringRef Attrs = GetEmptyOrTrim(3); + StringRef StubSizeStr = GetEmptyOrTrim(4); // Verify that the segment is present and not too long. if (Segment.empty() || Segment.size() > 16) return "mach-o section specifier requires a segment whose length is " "between 1 and 16 characters"; - // Split the section name off from any attributes if present. - Comma = Comma.second.split(','); - - // Capture section, remove leading and trailing whitespace. - Section = Comma.first; - StripSpaces(Section); - // Verify that the section is present and not too long. - if (Section.empty() || Section.size() > 16) + if (Section.empty()) + return "mach-o section specifier requires a segment and section " + "separated by a comma"; + + if (Section.size() > 16) return "mach-o section specifier requires a section whose length is " "between 1 and 16 characters"; // If there is no comma after the section, we're done. TAA = 0; StubSize = 0; - if (Comma.second.empty()) + if (SectionType.empty()) return ""; - // Otherwise, we need to parse the section type and attributes. - Comma = Comma.second.split(','); - - // Get the section type. - StringRef SectionType = Comma.first; - StripSpaces(SectionType); - // Figure out which section type it is. - unsigned TypeID; - for (TypeID = 0; TypeID != MachO::LAST_KNOWN_SECTION_TYPE + 1; ++TypeID) - if (SectionTypeDescriptors[TypeID].AssemblerName && - SectionType == SectionTypeDescriptors[TypeID].AssemblerName) - break; + auto TypeDescriptor = std::find_if( + std::begin(SectionTypeDescriptors), std::end(SectionTypeDescriptors), + [&](const decltype(*SectionTypeDescriptors) &Descriptor) { + return Descriptor.AssemblerName && + SectionType == Descriptor.AssemblerName; + }); // If we didn't find the section type, reject it. - if (TypeID > MachO::LAST_KNOWN_SECTION_TYPE) + if (TypeDescriptor == std::end(SectionTypeDescriptors)) return "mach-o section specifier uses an unknown section type"; // Remember the TypeID. - TAA = TypeID; + TAA = TypeDescriptor - std::begin(SectionTypeDescriptors); TAAParsed = true; // If we have no comma after the section type, there are no attributes. - if (Comma.second.empty()) { + if (Attrs.empty()) { // S_SYMBOL_STUBS always require a symbol stub size specifier. if (TAA == MachO::S_SYMBOL_STUBS) return "mach-o section specifier of type 'symbol_stubs' requires a size " @@ -250,36 +231,25 @@ std::string MCSectionMachO::ParseSectionSpecifier(StringRef Spec, // In. return ""; } - // Otherwise, we do have some attributes. Split off the size specifier if - // present. - Comma = Comma.second.split(','); - StringRef Attrs = Comma.first; - // The attribute list is a '+' separated list of attributes. - std::pair Plus = Attrs.split('+'); + SmallVector SectionAttrs; + Attrs.split(SectionAttrs, "+", /*MaxSplit=*/-1, /*KeepEmpty=*/false); - while (1) { - StringRef Attr = Plus.first; - StripSpaces(Attr); + for (StringRef &SectionAttr : SectionAttrs) { + auto AttrDescriptorI = std::find_if( + std::begin(SectionAttrDescriptors), std::end(SectionAttrDescriptors), + [&](const decltype(*SectionAttrDescriptors) &Descriptor) { + return Descriptor.AssemblerName && + SectionAttr.trim() == Descriptor.AssemblerName; + }); + if (AttrDescriptorI == std::end(SectionAttrDescriptors)) + return "mach-o section specifier has invalid attribute"; - // Look up the attribute. - for (unsigned i = 0; ; ++i) { - if (SectionAttrDescriptors[i].AttrFlag == AttrFlagEnd) - return "mach-o section specifier has invalid attribute"; - - if (SectionAttrDescriptors[i].AssemblerName && - Attr == SectionAttrDescriptors[i].AssemblerName) { - TAA |= SectionAttrDescriptors[i].AttrFlag; - break; - } - } - - if (Plus.second.empty()) break; - Plus = Plus.second.split('+'); - }; + TAA |= AttrDescriptorI->AttrFlag; + } // Okay, we've parsed the section attributes, see if we have a stub size spec. - if (Comma.second.empty()) { + if (StubSizeStr.empty()) { // S_SYMBOL_STUBS always require a symbol stub size specifier. if (TAA == MachO::S_SYMBOL_STUBS) return "mach-o section specifier of type 'symbol_stubs' requires a size " @@ -292,10 +262,6 @@ std::string MCSectionMachO::ParseSectionSpecifier(StringRef Spec, // In. return "mach-o section specifier cannot have a stub size specified because " "it does not have type 'symbol_stubs'"; - // Okay, if we do, it must be a number. - StringRef StubSizeStr = Comma.second; - StripSpaces(StubSizeStr); - // Convert the stub size from a string to an integer. if (StubSizeStr.getAsInteger(0, StubSize)) return "mach-o section specifier has a malformed stub size";