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[PowerPC] Generate little-endian object files

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As a first step towards real little-endian code generation, this patch
changes the PowerPC MC layer to actually generate little-endian object
files.  This involves passing the little-endian flag through the various
layers, including down to createELFObjectWriter so we actually get basic
little-endian ELF objects, emitting instructions in little-endian order,
and handling fixups and relocations as appropriate for little-endian.

The bulk of the patch is to update most test cases in test/MC/PowerPC
to verify both big- and little-endian encodings.  (The only test cases
*not* updated are those that create actual big-endian ABI code, like
the TLS tests.)

Note that while the object files are now little-endian, the generated
code itself is not yet updated, in particular, it still does not adhere
to the ELFv2 ABI.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204634 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Ulrich Weigand
2014-03-24 18:16:09 +00:00
parent 4768df00c4
commit 47eac58333
24 changed files with 6426 additions and 4098 deletions
Download Patch File Download Diff File Expand all files Collapse all files

41
lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
View File

@@ -71,14 +71,16 @@ static unsigned getFixupKindNumBytes(unsigned Kind) {
namespace {
class PPCAsmBackend : public MCAsmBackend {
const Target &TheTarget;
const Target &TheTarget;
bool IsLittleEndian;
public:
PPCAsmBackend(const Target &T) : MCAsmBackend(), TheTarget(T) {}
PPCAsmBackend(const Target &T, bool isLittle) : MCAsmBackend(), TheTarget(T),
IsLittleEndian(isLittle) {}
unsigned getNumFixupKinds() const { return PPC::NumTargetFixupKinds; }
const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const {
const static MCFixupKindInfo Infos[PPC::NumTargetFixupKinds] = {
const static MCFixupKindInfo InfosBE[PPC::NumTargetFixupKinds] = {
// name offset bits flags
{ "fixup_ppc_br24", 6, 24, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_ppc_brcond14", 16, 14, MCFixupKindInfo::FKF_IsPCRel },
@@ -88,13 +90,23 @@ public:
{ "fixup_ppc_half16ds", 0, 14, 0 },
{ "fixup_ppc_nofixup", 0, 0, 0 }
};
const static MCFixupKindInfo InfosLE[PPC::NumTargetFixupKinds] = {
// name offset bits flags
{ "fixup_ppc_br24", 2, 24, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_ppc_brcond14", 2, 14, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_ppc_br24abs", 2, 24, 0 },
{ "fixup_ppc_brcond14abs", 2, 14, 0 },
{ "fixup_ppc_half16", 0, 16, 0 },
{ "fixup_ppc_half16ds", 2, 14, 0 },
{ "fixup_ppc_nofixup", 0, 0, 0 }
};
if (Kind < FirstTargetFixupKind)
return MCAsmBackend::getFixupKindInfo(Kind);
assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
"Invalid kind!");
return Infos[Kind - FirstTargetFixupKind];
return (IsLittleEndian? InfosLE : InfosBE)[Kind - FirstTargetFixupKind];
}
void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
@@ -108,8 +120,10 @@ public:
// For each byte of the fragment that the fixup touches, mask in the bits
// from the fixup value. The Value has been "split up" into the appropriate
// bitfields above.
for (unsigned i = 0; i != NumBytes; ++i)
Data[Offset + i] |= uint8_t((Value >> ((NumBytes - i - 1)*8)) & 0xff);
for (unsigned i = 0; i != NumBytes; ++i) {
unsigned Idx = IsLittleEndian ? i : (NumBytes - 1 - i);
Data[Offset + i] |= uint8_t((Value >> (Idx * 8)) & 0xff);
}
}
bool mayNeedRelaxation(const MCInst &Inst) const {
@@ -152,6 +166,10 @@ public:
assert(Name == "ppc32" && "Unknown target name!");
return 4;
}
bool isLittleEndian() const {
return IsLittleEndian;
}
};
} // end anonymous namespace
@@ -160,7 +178,7 @@ public:
namespace {
class DarwinPPCAsmBackend : public PPCAsmBackend {
public:
DarwinPPCAsmBackend(const Target &T) : PPCAsmBackend(T) { }
DarwinPPCAsmBackend(const Target &T) : PPCAsmBackend(T, false) { }
MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
bool is64 = getPointerSize() == 8;
@@ -175,13 +193,13 @@ namespace {
class ELFPPCAsmBackend : public PPCAsmBackend {
uint8_t OSABI;
public:
ELFPPCAsmBackend(const Target &T, uint8_t OSABI) :
PPCAsmBackend(T), OSABI(OSABI) { }
ELFPPCAsmBackend(const Target &T, bool IsLittleEndian, uint8_t OSABI) :
PPCAsmBackend(T, IsLittleEndian), OSABI(OSABI) { }
MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
bool is64 = getPointerSize() == 8;
return createPPCELFObjectWriter(OS, is64, OSABI);
return createPPCELFObjectWriter(OS, is64, isLittleEndian(), OSABI);
}
};
@@ -194,5 +212,6 @@ MCAsmBackend *llvm::createPPCAsmBackend(const Target &T,
return new DarwinPPCAsmBackend(T);
uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS());
return new ELFPPCAsmBackend(T, OSABI);
bool IsLittleEndian = Triple(TT).getArch() == Triple::ppc64le;
return new ELFPPCAsmBackend(T, IsLittleEndian, OSABI);
}