[AIX]Emit function descriptor csect in assembly
This patch emits the function descriptor csect for functions with definitions
under both 32-bit/64-bit mode on AIX.
Differential Revision: https://reviews.llvm.org/D66724
llvm-svn: 373009
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 3a53a02..5664a47 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -91,10 +91,12 @@
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCSectionXCOFF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolELF.h"
+#include "llvm/MC/MCSymbolXCOFF.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/SectionKind.h"
@@ -426,7 +428,10 @@
OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
return;
case GlobalValue::PrivateLinkage:
+ return;
case GlobalValue::InternalLinkage:
+ if (MAI->hasDotLGloblDirective())
+ OutStreamer->EmitSymbolAttribute(GVSym, MCSA_LGlobal);
return;
case GlobalValue::AppendingLinkage:
case GlobalValue::AvailableExternallyLinkage:
@@ -662,6 +667,10 @@
OutStreamer->SwitchSection(getObjFileLowering().SectionForGlobal(&F, TM));
EmitVisibility(CurrentFnSym, F.getVisibility());
+ if (MAI->needsFunctionDescriptors() &&
+ F.getLinkage() != GlobalValue::InternalLinkage)
+ EmitLinkage(&F, CurrentFnDescSym);
+
EmitLinkage(&F, CurrentFnSym);
if (MAI->hasFunctionAlignment())
EmitAlignment(MF->getAlignment(), &F);
@@ -697,8 +706,13 @@
}
}
- // Emit the CurrentFnSym. This is a virtual function to allow targets to
- // do their wild and crazy things as required.
+ // Emit the function descriptor. This is a virtual function to allow targets
+ // to emit their specific function descriptor.
+ if (MAI->needsFunctionDescriptors())
+ EmitFunctionDescriptor();
+
+ // Emit the CurrentFnSym. This is a virtual function to allow targets to do
+ // their wild and crazy things as required.
EmitFunctionEntryLabel();
// If the function had address-taken blocks that got deleted, then we have
@@ -1644,8 +1658,27 @@
void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
this->MF = &MF;
+
// Get the function symbol.
- CurrentFnSym = getSymbol(&MF.getFunction());
+ if (MAI->needsFunctionDescriptors()) {
+ assert(TM.getTargetTriple().isOSAIX() && "Function descriptor is only"
+ " supported on AIX.");
+ assert(CurrentFnDescSym && "The function descriptor symbol needs to be"
+ " initalized first.");
+
+ // Get the function entry point symbol.
+ CurrentFnSym =
+ OutContext.getOrCreateSymbol("." + CurrentFnDescSym->getName());
+
+ const Function &F = MF.getFunction();
+ MCSectionXCOFF *FnEntryPointSec =
+ cast<MCSectionXCOFF>(getObjFileLowering().SectionForGlobal(&F, TM));
+ // Set the containing csect.
+ cast<MCSymbolXCOFF>(CurrentFnSym)->setContainingCsect(FnEntryPointSec);
+ } else {
+ CurrentFnSym = getSymbol(&MF.getFunction());
+ }
+
CurrentFnSymForSize = CurrentFnSym;
CurrentFnBegin = nullptr;
CurExceptionSym = nullptr;
diff --git a/llvm/lib/MC/MCAsmInfoXCOFF.cpp b/llvm/lib/MC/MCAsmInfoXCOFF.cpp
index 13939f6..65fe884 100644
--- a/llvm/lib/MC/MCAsmInfoXCOFF.cpp
+++ b/llvm/lib/MC/MCAsmInfoXCOFF.cpp
@@ -20,5 +20,16 @@
UseDotAlignForAlignment = true;
AsciiDirective = nullptr; // not supported
AscizDirective = nullptr; // not supported
+ NeedsFunctionDescriptors = true;
+ HasDotLGloblDirective = true;
Data64bitsDirective = "\t.llong\t";
+ SupportsQuotedNames = false;
+}
+
+bool MCAsmInfoXCOFF::isValidUnquotedName(StringRef Name) const {
+ // FIXME: Remove this function when we stop using "TOC[TC0]" as a symbol name.
+ if (Name.equals("TOC[TC0]"))
+ return true;
+
+ return MCAsmInfo::isValidUnquotedName(Name);
}
diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index 55bcc91..dd27d0b 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -650,6 +650,7 @@
case MCSA_Global: // .globl/.global
OS << MAI->getGlobalDirective();
break;
+ case MCSA_LGlobal: OS << "\t.lglobl\t"; break;
case MCSA_Hidden: OS << "\t.hidden\t"; break;
case MCSA_IndirectSymbol: OS << "\t.indirect_symbol\t"; break;
case MCSA_Internal: OS << "\t.internal\t"; break;
diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp
index 816e742..e411e24 100644
--- a/llvm/lib/MC/MCELFStreamer.cpp
+++ b/llvm/lib/MC/MCELFStreamer.cpp
@@ -277,6 +277,9 @@
case MCSA_AltEntry:
llvm_unreachable("ELF doesn't support the .alt_entry attribute");
+
+ case MCSA_LGlobal:
+ llvm_unreachable("ELF doesn't support the .lglobl attribute");
}
return true;
diff --git a/llvm/lib/MC/MCMachOStreamer.cpp b/llvm/lib/MC/MCMachOStreamer.cpp
index 613f255..8e558a3 100644
--- a/llvm/lib/MC/MCMachOStreamer.cpp
+++ b/llvm/lib/MC/MCMachOStreamer.cpp
@@ -330,6 +330,7 @@
case MCSA_Protected:
case MCSA_Weak:
case MCSA_Local:
+ case MCSA_LGlobal:
return false;
case MCSA_Global:
diff --git a/llvm/lib/MC/MCSectionXCOFF.cpp b/llvm/lib/MC/MCSectionXCOFF.cpp
index db27752..d52959f 100644
--- a/llvm/lib/MC/MCSectionXCOFF.cpp
+++ b/llvm/lib/MC/MCSectionXCOFF.cpp
@@ -15,26 +15,46 @@
MCSectionXCOFF::~MCSectionXCOFF() = default;
+static StringRef getMappingClassString(XCOFF::StorageMappingClass SMC) {
+ switch (SMC) {
+ case XCOFF::XMC_DS:
+ return "DS";
+ case XCOFF::XMC_RW:
+ return "RW";
+ case XCOFF::XMC_PR:
+ return "PR";
+ default:
+ report_fatal_error("Unhandled storage-mapping class.");
+ }
+}
+
void MCSectionXCOFF::PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
raw_ostream &OS,
const MCExpr *Subsection) const {
if (getKind().isText()) {
if (getMappingClass() != XCOFF::XMC_PR)
- llvm_unreachable("Unsupported storage-mapping class for .text csect");
+ report_fatal_error("Unhandled storage-mapping class for .text csect");
OS << "\t.csect " << getSectionName() << "["
- << "PR"
+ << getMappingClassString(getMappingClass())
<< "]" << '\n';
return;
}
if (getKind().isData()) {
- assert(getMappingClass() == XCOFF::XMC_RW &&
- "Unhandled storage-mapping class for data section.");
-
- OS << "\t.csect " << getSectionName() << "["
- << "RW"
- << "]" << '\n';
+ switch (getMappingClass()) {
+ case XCOFF::XMC_RW:
+ case XCOFF::XMC_DS:
+ OS << "\t.csect " << getSectionName() << "["
+ << getMappingClassString(getMappingClass()) << "]" << '\n';
+ break;
+ case XCOFF::XMC_TC0:
+ OS << "\t.toc\n";
+ break;
+ default:
+ report_fatal_error(
+ "Unhandled storage-mapping class for .data csect.");
+ }
return;
}
diff --git a/llvm/lib/MC/XCOFFObjectWriter.cpp b/llvm/lib/MC/XCOFFObjectWriter.cpp
index e831d3e..5d8735b 100644
--- a/llvm/lib/MC/XCOFFObjectWriter.cpp
+++ b/llvm/lib/MC/XCOFFObjectWriter.cpp
@@ -235,6 +235,9 @@
break;
}
report_fatal_error("Unhandled mapping of read-write csect to section.");
+ case XCOFF::XMC_TC0:
+ // TODO FIXME Handle emiting the TOC base.
+ break;
case XCOFF::XMC_BS:
assert(XCOFF::XTY_CM == MCSec->getCSectType() &&
"Mapping invalid csect. CSECT with bss storage class must be "
diff --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 6e0fdd8..124c182 100644
--- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -167,7 +167,13 @@
StringRef getPassName() const override { return "AIX PPC Assembly Printer"; }
+ void SetupMachineFunction(MachineFunction &MF) override;
+
void EmitGlobalVariable(const GlobalVariable *GV) override;
+
+ void EmitFunctionDescriptor() override;
+
+ void EmitEndOfAsmFile(Module &) override;
};
} // end anonymous namespace
@@ -1669,6 +1675,18 @@
return AsmPrinter::doFinalization(M);
}
+void PPCAIXAsmPrinter::SetupMachineFunction(MachineFunction &MF) {
+ // Get the function descriptor symbol.
+ CurrentFnDescSym = getSymbol(&MF.getFunction());
+ // Set the containing csect.
+ MCSectionXCOFF *FnDescSec = OutStreamer->getContext().getXCOFFSection(
+ CurrentFnDescSym->getName(), XCOFF::XMC_DS, XCOFF::XTY_SD,
+ XCOFF::C_HIDEXT, SectionKind::getData());
+ cast<MCSymbolXCOFF>(CurrentFnDescSym)->setContainingCsect(FnDescSec);
+
+ return AsmPrinter::SetupMachineFunction(MF);
+}
+
void PPCAIXAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
// Early error checking limiting what is supported.
if (GV->isThreadLocal())
@@ -1718,6 +1736,45 @@
EmitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer());
}
+void PPCAIXAsmPrinter::EmitFunctionDescriptor() {
+ const DataLayout &DL = getDataLayout();
+ const unsigned PointerSize = DL.getPointerSizeInBits() == 64 ? 8 : 4;
+
+ MCSectionSubPair Current = OutStreamer->getCurrentSection();
+ // Emit function descriptor.
+ OutStreamer->SwitchSection(
+ cast<MCSymbolXCOFF>(CurrentFnDescSym)->getContainingCsect());
+ OutStreamer->EmitLabel(CurrentFnDescSym);
+ // Emit function entry point address.
+ OutStreamer->EmitValue(MCSymbolRefExpr::create(CurrentFnSym, OutContext),
+ PointerSize);
+ // Emit TOC base address.
+ MCSymbol *TOCBaseSym = OutContext.getOrCreateSymbol(StringRef("TOC[TC0]"));
+ OutStreamer->EmitValue(MCSymbolRefExpr::create(TOCBaseSym, OutContext),
+ PointerSize);
+ // Emit a null environment pointer.
+ OutStreamer->EmitIntValue(0, PointerSize);
+
+ OutStreamer->SwitchSection(Current.first, Current.second);
+}
+
+void PPCAIXAsmPrinter::EmitEndOfAsmFile(Module &M) {
+ // If there are no functions in this module, we will never need to reference
+ // the TOC base.
+ if (M.empty())
+ return;
+
+ // Emit TOC base.
+ MCSymbol *TOCBaseSym = OutContext.getOrCreateSymbol(StringRef("TOC[TC0]"));
+ MCSectionXCOFF *TOCBaseSection = OutStreamer->getContext().getXCOFFSection(
+ StringRef("TOC"), XCOFF::XMC_TC0, XCOFF::XTY_SD, XCOFF::C_HIDEXT,
+ SectionKind::getData());
+ cast<MCSymbolXCOFF>(TOCBaseSym)->setContainingCsect(TOCBaseSection);
+ // Switch to section to emit TOC base.
+ OutStreamer->SwitchSection(TOCBaseSection);
+}
+
+
/// createPPCAsmPrinterPass - Returns a pass that prints the PPC assembly code
/// for a MachineFunction to the given output stream, in a format that the
/// Darwin assembler can deal with.