resolve a fixme: the "nonexecutable stack directive" is actually
a .section. Switch to it with SwitchSection.
However, I think that this directive should be safe on any ELF target.
If so, we should hoist it up out of the X86 and SystemZ targets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94298 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/MC/MCAsmInfo.h b/include/llvm/MC/MCAsmInfo.h
index 1a93d75..22939b5 100644
--- a/include/llvm/MC/MCAsmInfo.h
+++ b/include/llvm/MC/MCAsmInfo.h
@@ -20,6 +20,9 @@
#include <cassert>
namespace llvm {
+ class MCSection;
+ class MCContext;
+
/// MCAsmInfo - This class is intended to be used as a base class for asm
/// properties and features specific to the target.
namespace ExceptionHandling { enum ExceptionsType { None, Dwarf, SjLj }; }
@@ -30,11 +33,10 @@
// Properties to be set by the target writer, used to configure asm printer.
//
- /// NonexecutableStackDirective - Directive for declaring to the
- /// linker and beyond that the emitted code does not require stack
- /// memory to be executable.
- const char *NonexecutableStackDirective; // Default is null.
-
+ /// HasSubsectionsViaSymbols - True if this target has the MachO
+ /// .subsections_via_symbols directive.
+ bool HasSubsectionsViaSymbols; // Default is false.
+
/// HasMachoZeroFillDirective - True if this is a MachO target that supports
/// the macho-specific .zerofill directive for emitting BSS Symbols.
bool HasMachoZeroFillDirective; // Default is false.
@@ -288,14 +290,12 @@
explicit MCAsmInfo();
virtual ~MCAsmInfo();
- /// getSLEB128Size - Compute the number of bytes required for a signed
- /// leb128 value.
+ // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
static unsigned getSLEB128Size(int Value);
-
- /// getULEB128Size - Compute the number of bytes required for an unsigned
- /// leb128 value.
static unsigned getULEB128Size(unsigned Value);
+ bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
+
// Data directive accessors.
//
const char *getData8bitsDirective(unsigned AS = 0) const {
@@ -311,6 +311,12 @@
return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
}
+ /// getNonexecutableStackSection - Targets can implement this method to
+ /// specify a section to switch to if the translation unit doesn't have any
+ /// trampolines that require an executable stack.
+ virtual MCSection *getNonexecutableStackSection(MCContext &Ctx) const {
+ return 0;
+ }
bool usesSunStyleELFSectionSwitchSyntax() const {
return SunStyleELFSectionSwitchSyntax;
@@ -326,9 +332,6 @@
bool hasStaticCtorDtorReferenceInStaticMode() const {
return HasStaticCtorDtorReferenceInStaticMode;
}
- const char *getNonexecutableStackDirective() const {
- return NonexecutableStackDirective;
- }
bool needsSet() const {
return NeedsSet;
}
diff --git a/include/llvm/MC/MCSectionELF.h b/include/llvm/MC/MCSectionELF.h
index c48ff03..2dccf5c 100644
--- a/include/llvm/MC/MCSectionELF.h
+++ b/include/llvm/MC/MCSectionELF.h
@@ -31,7 +31,7 @@
unsigned Flags;
/// IsExplicit - Indicates that this section comes from globals with an
- /// explicit section specfied.
+ /// explicit section specified.
bool IsExplicit;
protected:
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 7238a52..fc2c5a0 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -345,11 +345,8 @@
// to be executable. Some targets have a directive to declare this.
Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
- // FIXME: This is actually a section switch on linux/x86 and systemz, use
- // switch section.
- if (MAI->getNonexecutableStackDirective())
- O << MAI->getNonexecutableStackDirective() << '\n';
-
+ if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
+ OutStreamer.SwitchSection(S);
// Allow the target to emit any magic that it wants at the end of the file,
// after everything else has gone out.
diff --git a/lib/MC/MCAsmInfo.cpp b/lib/MC/MCAsmInfo.cpp
index debccaf..b96b4e9 100644
--- a/lib/MC/MCAsmInfo.cpp
+++ b/lib/MC/MCAsmInfo.cpp
@@ -19,9 +19,9 @@
using namespace llvm;
MCAsmInfo::MCAsmInfo() {
+ HasSubsectionsViaSymbols = false;
HasMachoZeroFillDirective = false;
HasStaticCtorDtorReferenceInStaticMode = false;
- NonexecutableStackDirective = 0;
NeedsSet = false;
MaxInstLength = 4;
PCSymbol = "$";
diff --git a/lib/MC/MCAsmInfoDarwin.cpp b/lib/MC/MCAsmInfoDarwin.cpp
index 8495aa4..9902f50 100644
--- a/lib/MC/MCAsmInfoDarwin.cpp
+++ b/lib/MC/MCAsmInfoDarwin.cpp
@@ -24,6 +24,7 @@
NeedsSet = true;
AllowQuotesInName = true;
HasSingleParameterDotFile = false;
+ HasSubsectionsViaSymbols = true;
AlignmentIsInBytes = false;
InlineAsmStart = " InlineAsm Start";
diff --git a/lib/Target/SystemZ/SystemZMCAsmInfo.cpp b/lib/Target/SystemZ/SystemZMCAsmInfo.cpp
index 8ea11c9..ba392bb 100644
--- a/lib/Target/SystemZ/SystemZMCAsmInfo.cpp
+++ b/lib/Target/SystemZ/SystemZMCAsmInfo.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "SystemZMCAsmInfo.h"
+#include "llvm/MC/MCSectionELF.h"
using namespace llvm;
SystemZMCAsmInfo::SystemZMCAsmInfo(const Target &T, const StringRef &TT) {
@@ -21,6 +22,9 @@
WeakRefDirective = "\t.weak\t";
SetDirective = "\t.set\t";
PCSymbol = ".";
+}
- NonexecutableStackDirective = "\t.section\t.note.GNU-stack,\"\",@progbits";
+MCSection *SystemZMCAsmInfo::getNonexecutableStackSection(MCContext &Ctx) const{
+ return MCSectionELF::Create(".note.GNU-stack", MCSectionELF::SHT_PROGBITS,
+ 0, SectionKind::getMetadata(), false, Ctx);
}
diff --git a/lib/Target/SystemZ/SystemZMCAsmInfo.h b/lib/Target/SystemZ/SystemZMCAsmInfo.h
index 3bebcb7..00cb99b 100644
--- a/lib/Target/SystemZ/SystemZMCAsmInfo.h
+++ b/lib/Target/SystemZ/SystemZMCAsmInfo.h
@@ -22,8 +22,9 @@
struct SystemZMCAsmInfo : public MCAsmInfo {
explicit SystemZMCAsmInfo(const Target &T, const StringRef &TT);
+ virtual MCSection *getNonexecutableStackSection(MCContext &Ctx) const;
};
-
+
} // namespace llvm
#endif
diff --git a/lib/Target/X86/X86MCAsmInfo.cpp b/lib/Target/X86/X86MCAsmInfo.cpp
index 001ce80..1738d49 100644
--- a/lib/Target/X86/X86MCAsmInfo.cpp
+++ b/lib/Target/X86/X86MCAsmInfo.cpp
@@ -14,6 +14,7 @@
#include "X86MCAsmInfo.h"
#include "X86TargetMachine.h"
#include "llvm/ADT/Triple.h"
+#include "llvm/MC/MCSectionELF.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
@@ -87,10 +88,11 @@
// Exceptions handling
ExceptionsType = ExceptionHandling::Dwarf;
AbsoluteEHSectionOffsets = false;
+}
- // On Linux we must declare when we can use a non-executable stack.
- if (Triple.getOS() == Triple::Linux)
- NonexecutableStackDirective = "\t.section\t.note.GNU-stack,\"\",@progbits";
+MCSection *X86ELFMCAsmInfo::getNonexecutableStackSection(MCContext &Ctx) const {
+ return MCSectionELF::Create(".note.GNU-stack", MCSectionELF::SHT_PROGBITS,
+ 0, SectionKind::getMetadata(), false, Ctx);
}
X86MCAsmInfoCOFF::X86MCAsmInfoCOFF(const Triple &Triple) {
diff --git a/lib/Target/X86/X86MCAsmInfo.h b/lib/Target/X86/X86MCAsmInfo.h
index 18e2bdb..ca227b7 100644
--- a/lib/Target/X86/X86MCAsmInfo.h
+++ b/lib/Target/X86/X86MCAsmInfo.h
@@ -27,6 +27,7 @@
struct X86ELFMCAsmInfo : public MCAsmInfo {
explicit X86ELFMCAsmInfo(const Triple &Triple);
+ virtual MCSection *getNonexecutableStackSection(MCContext &Ctx) const;
};
struct X86MCAsmInfoCOFF : public MCAsmInfoCOFF {