MC: Add .section directive to COFF
Supports GAS flags "abdnrswxy". No support for alignment or subsections.
Fixes PR16366.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185669 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCParser/COFFAsmParser.cpp b/lib/MC/MCParser/COFFAsmParser.cpp
index ad8f84c..c2a2261 100644
--- a/lib/MC/MCParser/COFFAsmParser.cpp
+++ b/lib/MC/MCParser/COFFAsmParser.cpp
@@ -35,6 +35,9 @@
unsigned Characteristics,
SectionKind Kind);
+ bool ParseSectionName(StringRef &SectionName);
+ bool ParseSectionFlags(StringRef FlagsString, unsigned* Flags);
+
virtual void Initialize(MCAsmParser &Parser) {
// Call the base implementation.
MCAsmParserExtension::Initialize(Parser);
@@ -42,6 +45,7 @@
addDirectiveHandler<&COFFAsmParser::ParseSectionDirectiveText>(".text");
addDirectiveHandler<&COFFAsmParser::ParseSectionDirectiveData>(".data");
addDirectiveHandler<&COFFAsmParser::ParseSectionDirectiveBSS>(".bss");
+ addDirectiveHandler<&COFFAsmParser::ParseDirectiveSection>(".section");
addDirectiveHandler<&COFFAsmParser::ParseDirectiveDef>(".def");
addDirectiveHandler<&COFFAsmParser::ParseDirectiveScl>(".scl");
addDirectiveHandler<&COFFAsmParser::ParseDirectiveType>(".type");
@@ -100,6 +104,7 @@
SectionKind::getBSS());
}
+ bool ParseDirectiveSection(StringRef, SMLoc);
bool ParseDirectiveDef(StringRef, SMLoc);
bool ParseDirectiveScl(StringRef, SMLoc);
bool ParseDirectiveType(StringRef, SMLoc);
@@ -130,6 +135,119 @@
} // end annonomous namespace.
+static SectionKind computeSectionKind(unsigned Flags) {
+ if (Flags & COFF::IMAGE_SCN_MEM_EXECUTE)
+ return SectionKind::getText();
+ if (Flags & COFF::IMAGE_SCN_MEM_READ &&
+ (Flags & COFF::IMAGE_SCN_MEM_WRITE) == 0)
+ return SectionKind::getReadOnly();
+ return SectionKind::getDataRel();
+}
+
+bool COFFAsmParser::ParseSectionFlags(StringRef FlagsString, unsigned* Flags) {
+ enum {
+ None = 0,
+ Alloc = 1 << 0,
+ Code = 1 << 1,
+ Load = 1 << 2,
+ InitData = 1 << 3,
+ Shared = 1 << 4,
+ NoLoad = 1 << 5,
+ NoRead = 1 << 6,
+ NoWrite = 1 << 7
+ };
+
+ bool ReadOnlyRemoved = false;
+ unsigned SecFlags = None;
+
+ for (unsigned i = 0; i < FlagsString.size(); ++i) {
+ switch (FlagsString[i]) {
+ case 'a':
+ // Ignored.
+ break;
+
+ case 'b': // bss section
+ SecFlags |= Alloc;
+ if (SecFlags & InitData)
+ return TokError("conflicting section flags 'b' and 'd'.");
+ SecFlags &= ~Load;
+ break;
+
+ case 'd': // data section
+ SecFlags |= InitData;
+ if (SecFlags & Alloc)
+ return TokError("conflicting section flags 'b' and 'd'.");
+ SecFlags &= ~NoWrite;
+ if ((SecFlags & NoLoad) == 0)
+ SecFlags |= Load;
+ break;
+
+ case 'n': // section is not loaded
+ SecFlags |= NoLoad;
+ SecFlags &= ~Load;
+ break;
+
+ case 'r': // read-only
+ ReadOnlyRemoved = false;
+ SecFlags |= NoWrite;
+ if ((SecFlags & Code) == 0)
+ SecFlags |= InitData;
+ if ((SecFlags & NoLoad) == 0)
+ SecFlags |= Load;
+ break;
+
+ case 's': // shared section
+ SecFlags |= Shared | InitData;
+ SecFlags &= ~NoWrite;
+ if ((SecFlags & NoLoad) == 0)
+ SecFlags |= Load;
+ break;
+
+ case 'w': // writable
+ SecFlags &= ~NoWrite;
+ ReadOnlyRemoved = true;
+ break;
+
+ case 'x': // executable section
+ SecFlags |= Code;
+ if ((SecFlags & NoLoad) == 0)
+ SecFlags |= Load;
+ if (!ReadOnlyRemoved)
+ SecFlags |= NoWrite;
+ break;
+
+ case 'y': // not readable
+ SecFlags |= NoRead | NoWrite;
+ break;
+
+ default:
+ return TokError("unknown flag");
+ }
+ }
+
+ *Flags = 0;
+
+ if (SecFlags == None)
+ SecFlags = InitData;
+
+ if (SecFlags & Code)
+ *Flags |= COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE;
+ if (SecFlags & InitData)
+ *Flags |= COFF::IMAGE_SCN_CNT_INITIALIZED_DATA;
+ if ((SecFlags & Alloc) && (SecFlags & Load) == 0)
+ *Flags |= COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
+ if (SecFlags & NoLoad)
+ *Flags |= COFF::IMAGE_SCN_LNK_REMOVE;
+ if ((SecFlags & NoRead) == 0)
+ *Flags |= COFF::IMAGE_SCN_MEM_READ;
+ if ((SecFlags & NoWrite) == 0)
+ *Flags |= COFF::IMAGE_SCN_MEM_WRITE;
+ if (SecFlags & Shared)
+ *Flags |= COFF::IMAGE_SCN_MEM_SHARED;
+
+ return false;
+}
+
/// ParseDirectiveSymbolAttribute
/// ::= { ".weak", ... } [ identifier ( , identifier )* ]
bool COFFAsmParser::ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
@@ -174,6 +292,60 @@
return false;
}
+bool COFFAsmParser::ParseSectionName(StringRef &SectionName) {
+ if (!getLexer().is(AsmToken::Identifier))
+ return true;
+
+ SectionName = getTok().getIdentifier();
+ Lex();
+ return false;
+}
+
+// .section name [, "flags"]
+//
+// Supported flags:
+// a: Ignored.
+// b: BSS section (uninitialized data)
+// d: data section (initialized data)
+// n: Discardable section
+// r: Readable section
+// s: Shared section
+// w: Writable section
+// x: Executable section
+// y: Not-readable section (clears 'r')
+//
+// Subsections are not supported.
+bool COFFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
+ StringRef SectionName;
+
+ if (ParseSectionName(SectionName))
+ return TokError("expected identifier in directive");
+
+ unsigned Flags = COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
+ COFF::IMAGE_SCN_MEM_READ |
+ COFF::IMAGE_SCN_MEM_WRITE;
+
+ if (getLexer().is(AsmToken::Comma)) {
+ Lex();
+
+ if (getLexer().isNot(AsmToken::String))
+ return TokError("expected string in directive");
+
+ StringRef FlagsStr = getTok().getStringContents();
+ Lex();
+
+ if (ParseSectionFlags(FlagsStr, &Flags))
+ return true;
+ }
+
+ if (getLexer().isNot(AsmToken::EndOfStatement))
+ return TokError("unexpected token in directive");
+
+ SectionKind Kind = computeSectionKind(Flags);
+ ParseSectionSwitch(SectionName, Flags, Kind);
+ return false;
+}
+
bool COFFAsmParser::ParseDirectiveDef(StringRef, SMLoc) {
StringRef SymbolName;