Add support for pushsection and popsection. Patch by Joerg Sonnenberger.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125629 91177308-0d34-0410-b5e6-96231b3b80d8

9 files changed, 53 insertions, 42 deletions

diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 6aabfe188a..8d0698216f 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -107,7 +107,7 @@ public:
   /// @name MCStreamer Interface
   /// @{
 
-  virtual void SwitchSection(const MCSection *Section);
+  virtual void ChangeSection(const MCSection *Section);
 
   virtual void InitSections() {
     // FIXME, this is MachO specific, but the testsuite
@@ -254,23 +254,19 @@ static inline int64_t truncateToSize(int64_t Value, unsigned Bytes) {
   return Value & ((uint64_t) (int64_t) -1 >> (64 - Bytes * 8));
 }
 
-void MCAsmStreamer::SwitchSection(const MCSection *Section) {
+void MCAsmStreamer::ChangeSection(const MCSection *Section) {
   assert(Section && "Cannot switch to a null section!");
-  if (Section != CurSection) {
-    PrevSection = CurSection;
-    CurSection = Section;
-    Section->PrintSwitchToSection(MAI, OS);
-  }
+  Section->PrintSwitchToSection(MAI, OS);
 }
 
 void MCAsmStreamer::EmitLabel(MCSymbol *Symbol) {
   assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
-  assert(CurSection && "Cannot emit before setting section!");
+  assert(getCurrentSection() && "Cannot emit before setting section!");
 
   OS << *Symbol << MAI.getLabelSuffix();
   EmitEOL();
-  Symbol->setSection(*CurSection);
+  Symbol->setSection(*getCurrentSection());
 }
 
 void MCAsmStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
@@ -486,7 +482,7 @@ static void PrintQuotedString(StringRef Data, raw_ostream &OS) {
 
 
 void MCAsmStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
-  assert(CurSection && "Cannot emit contents before setting section!");
+  assert(getCurrentSection() && "Cannot emit contents before setting section!");
   if (Data.empty()) return;
 
   if (Data.size() == 1) {
@@ -517,7 +513,7 @@ void MCAsmStreamer::EmitIntValue(uint64_t Value, unsigned Size,
 
 void MCAsmStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
                                   bool isPCRel, unsigned AddrSpace) {
-  assert(CurSection && "Cannot emit contents before setting section!");
+  assert(getCurrentSection() && "Cannot emit contents before setting section!");
   assert(!isPCRel && "Cannot emit pc relative relocations!");
   const char *Directive = 0;
   switch (Size) {
@@ -864,7 +860,7 @@ void MCAsmStreamer::AddEncodingComment(const MCInst &Inst) {
 }
 
 void MCAsmStreamer::EmitInstruction(const MCInst &Inst) {
-  assert(CurSection && "Cannot emit contents before setting section!");
+  assert(getCurrentSection() && "Cannot emit contents before setting section!");
 
   if (!UseLoc)
     MCLineEntry::Make(this, getCurrentSection());
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index ac31057065..e49074da39 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -80,12 +80,12 @@ public:
   /// @{
 
   virtual void InitSections();
+  virtual void ChangeSection(const MCSection *Section);
   virtual void EmitLabel(MCSymbol *Symbol);
   virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
   virtual void EmitThumbFunc(MCSymbol *Func);
   virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
   virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
-  virtual void SwitchSection(const MCSection *Section);
   virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
   virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
     assert(0 && "ELF doesn't support this directive");
@@ -222,11 +222,11 @@ void MCELFStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
   Symbol->setVariableValue(AddValueSymbols(Value));
 }
 
-void MCELFStreamer::SwitchSection(const MCSection *Section) {
+void MCELFStreamer::ChangeSection(const MCSection *Section) {
   const MCSymbol *Grp = static_cast<const MCSectionELF *>(Section)->getGroup();
   if (Grp)
     getAssembler().getOrCreateSymbolData(*Grp);
-  this->MCObjectStreamer::SwitchSection(Section);
+  this->MCObjectStreamer::ChangeSection(Section);
 }
 
 void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {
@@ -411,7 +411,7 @@ void MCELFStreamer::EmitCodeAlignment(unsigned ByteAlignment,
 // entry in the module's symbol table (the first being the null symbol).
 void MCELFStreamer::EmitFileDirective(StringRef Filename) {
   MCSymbol *Symbol = getAssembler().getContext().GetOrCreateSymbol(Filename);
-  Symbol->setSection(*CurSection);
+  Symbol->setSection(*getCurrentSection());
   Symbol->setAbsolute();
 
   MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
diff --git a/lib/MC/MCLoggingStreamer.cpp b/lib/MC/MCLoggingStreamer.cpp
index d947481383..012c7f62f8 100644
--- a/lib/MC/MCLoggingStreamer.cpp
+++ b/lib/MC/MCLoggingStreamer.cpp
@@ -48,10 +48,9 @@ public:
     return Child->AddBlankLine();
   }
 
-  virtual void SwitchSection(const MCSection *Section) {
-    CurSection = Section;
-    LogCall("SwitchSection");
-    return Child->SwitchSection(Section);
+  virtual void ChangeSection(const MCSection *Section) {
+    LogCall("ChangeSection");
+    return Child->ChangeSection(Section);
   }
 
   virtual void InitSections() {
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 7e1cda25b6..d1f9f5cd56 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -105,7 +105,7 @@ void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
   assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
 
   // isSymbolLinkerVisible uses the section.
-  Symbol->setSection(*CurSection);
+  Symbol->setSection(*getCurrentSection());
   // We have to create a new fragment if this is an atom defining symbol,
   // fragments cannot span atoms.
   if (getAssembler().isSymbolLinkerVisible(*Symbol))
diff --git a/lib/MC/MCNullStreamer.cpp b/lib/MC/MCNullStreamer.cpp
index b9393ffd2e..08ddf01d1a 100644
--- a/lib/MC/MCNullStreamer.cpp
+++ b/lib/MC/MCNullStreamer.cpp
@@ -28,15 +28,13 @@ namespace {
     virtual void InitSections() {
     }
 
-    virtual void SwitchSection(const MCSection *Section) {
-      PrevSection = CurSection;
-      CurSection = Section;
+    virtual void ChangeSection(const MCSection *Section) {
     }
 
     virtual void EmitLabel(MCSymbol *Symbol) {
       assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
-      assert(CurSection && "Cannot emit before setting section!");
-      Symbol->setSection(*CurSection);
+      assert(getCurrentSection() && "Cannot emit before setting section!");
+      Symbol->setSection(*getCurrentSection());
     }
 
     virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {}
diff --git a/lib/MC/MCObjectStreamer.cpp b/lib/MC/MCObjectStreamer.cpp
index ecd7257c70..035826690c 100644
--- a/lib/MC/MCObjectStreamer.cpp
+++ b/lib/MC/MCObjectStreamer.cpp
@@ -101,9 +101,9 @@ void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
 
 void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
-  assert(CurSection && "Cannot emit before setting section!");
+  assert(getCurrentSection() && "Cannot emit before setting section!");
 
-  Symbol->setSection(*CurSection);
+  Symbol->setSection(*getCurrentSection());
 
   MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
 
@@ -142,14 +142,9 @@ void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
   report_fatal_error("This file format doesn't support weak aliases.");
 }
 
-void MCObjectStreamer::SwitchSection(const MCSection *Section) {
+void MCObjectStreamer::ChangeSection(const MCSection *Section) {
   assert(Section && "Cannot switch to a null section!");
 
-  // If already in this section, then this is a noop.
-  if (Section == CurSection) return;
-
-  PrevSection = CurSection;
-  CurSection = Section;
   CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
 }
 
diff --git a/lib/MC/MCParser/ELFAsmParser.cpp b/lib/MC/MCParser/ELFAsmParser.cpp
index 7b88ea2d1d..bfaf36a451 100644
--- a/lib/MC/MCParser/ELFAsmParser.cpp
+++ b/lib/MC/MCParser/ELFAsmParser.cpp
@@ -49,6 +49,8 @@ public:
     AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveDataRelRoLocal>(".data.rel.ro.local");
     AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveEhFrame>(".eh_frame");
     AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSection>(".section");
+    AddDirectiveHandler<&ELFAsmParser::ParseDirectivePushSection>(".pushsection");
+    AddDirectiveHandler<&ELFAsmParser::ParseDirectivePopSection>(".popsection");
     AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSize>(".size");
     AddDirectiveHandler<&ELFAsmParser::ParseDirectivePrevious>(".previous");
     AddDirectiveHandler<&ELFAsmParser::ParseDirectiveType>(".type");
@@ -115,6 +117,8 @@ public:
                               ELF::SHF_WRITE,
                               SectionKind::getDataRel());
   }
+  bool ParseDirectivePushSection(StringRef, SMLoc);
+  bool ParseDirectivePopSection(StringRef, SMLoc);
   bool ParseDirectiveSection(StringRef, SMLoc);
   bool ParseDirectiveSize(StringRef, SMLoc);
   bool ParseDirectivePrevious(StringRef, SMLoc);
@@ -253,6 +257,23 @@ static int parseSectionFlags(StringRef flagsStr) {
   return flags;
 }
 
+bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) {
+  getStreamer().PushSection();
+
+  if (ParseDirectiveSection(s, loc)) {
+    getStreamer().PopSection();
+    return true;
+  }
+
+  return false;
+}
+
+bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
+  if (!getStreamer().PopSection())
+    return TokError(".popsection without corresponding .pushsection");
+  return false;
+}
+
 // FIXME: This is a work in progress.
 bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
   StringRef SectionName;
@@ -364,8 +385,9 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
 
 bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
   const MCSection *PreviousSection = getStreamer().getPreviousSection();
-  if (PreviousSection != NULL)
-    getStreamer().SwitchSection(PreviousSection);
+  if (PreviousSection == NULL)
+      return TokError(".previous without corresponding .section");
+  getStreamer().SwitchSection(PreviousSection);
 
   return false;
 }
@@ -427,7 +449,6 @@ bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
 
   Lex();
 
-  const MCSection *OldSection = getStreamer().getCurrentSection();
   const MCSection *Comment =
     getContext().getELFSection(".comment", ELF::SHT_PROGBITS,
                                ELF::SHF_MERGE |
@@ -437,13 +458,14 @@ bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
 
   static bool First = true;
 
+  getStreamer().PushSection();
   getStreamer().SwitchSection(Comment);
   if (First)
     getStreamer().EmitIntValue(0, 1);
   First = false;
   getStreamer().EmitBytes(Data, 0);
   getStreamer().EmitIntValue(0, 1);
-  getStreamer().SwitchSection(OldSection);
+  getStreamer().PopSection();
   return false;
 }
 
diff --git a/lib/MC/MCPureStreamer.cpp b/lib/MC/MCPureStreamer.cpp
index 5341844f74..6098e6b8f3 100644
--- a/lib/MC/MCPureStreamer.cpp
+++ b/lib/MC/MCPureStreamer.cpp
@@ -113,9 +113,9 @@ void MCPureStreamer::InitSections() {
 void MCPureStreamer::EmitLabel(MCSymbol *Symbol) {
   assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
-  assert(CurSection && "Cannot emit before setting section!");
+  assert(getCurrentSection() && "Cannot emit before setting section!");
 
-  Symbol->setSection(*CurSection);
+  Symbol->setSection(*getCurrentSection());
 
   MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
 
diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp
index 1cb5165e6d..3dcdba1313 100644
--- a/lib/MC/MCStreamer.cpp
+++ b/lib/MC/MCStreamer.cpp
@@ -19,8 +19,9 @@
 #include <cstdlib>
 using namespace llvm;
 
-MCStreamer::MCStreamer(MCContext &Ctx) : Context(Ctx), CurSection(0),
-                                         PrevSection(0) {
+MCStreamer::MCStreamer(MCContext &Ctx) : Context(Ctx) {
+  PrevSectionStack.push_back(NULL);
+  CurSectionStack.push_back(NULL);
 }
 
 MCStreamer::~MCStreamer() {