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[SPARC][MC] Fix %gdop_hix22() and %gdop_lox10() to use correct relocations (#137915)

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1bfc5e7 introduced support for `%gdop_hix22()` and `%gdop_lox10()`.
However, it incorrectly mapped them to `R_SPARC_GOTDATA_HIX22` and
`R_SPARC_GOTDATA_LOX10`. They should in fact emit
`R_SPARC_GOTDATA_OP_HIX22` and `R_SPARC_GOTDATA_OP_LOX10`.

This became a problem when assembling glibc's PIC startup code:

```asm
sethi %gdop_hix22(main), %o0
xor %o0, %gdop_lox10(main), %o0
ldx [%l7 + %o0], %o0, %gdop(main)
```

After the `xor`, `%o0` should contain the GOT offset for `main`, but
because of the incorrect relocations, it actually ends up containing the
address of `main`, which of course makes the following `ldx` fail.
This commit is contained in:
Alex Rønne Petersen
2025-05-04 21:32:17 +02:00
committed by GitHub
parent 4c587f549c
commit c3ff3b2ba3
6 changed files with 18 additions and 33 deletions
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13
llvm/lib/Target/Sparc/MCTargetDesc/SparcAsmBackend.cpp
View File

@@ -82,11 +82,6 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
case Sparc::fixup_sparc_hm:
return (Value >> 32) & 0x3ff;
case Sparc::fixup_sparc_gotdata_lox10:
case Sparc::fixup_sparc_gotdata_hix22:
case Sparc::fixup_sparc_gotdata_op:
return 0;
}
}
@@ -137,6 +132,7 @@ namespace {
}
MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override {
// clang-format off
const static MCFixupKindInfo InfosBE[Sparc::NumTargetFixupKinds] = {
// name offset bits flags
{ "fixup_sparc_call30", 2, 30, MCFixupKindInfo::FKF_IsPCRel },
@@ -157,9 +153,6 @@ namespace {
{ "fixup_sparc_wplt30", 2, 30, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_sparc_hix22", 10, 22, 0 },
{ "fixup_sparc_lox10", 19, 13, 0 },
{ "fixup_sparc_gotdata_hix22", 0, 0, 0 },
{ "fixup_sparc_gotdata_lox10", 0, 0, 0 },
{ "fixup_sparc_gotdata_op", 0, 0, 0 },
};
const static MCFixupKindInfo InfosLE[Sparc::NumTargetFixupKinds] = {
@@ -182,10 +175,8 @@ namespace {
{ "fixup_sparc_wplt30", 0, 30, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_sparc_hix22", 0, 22, 0 },
{ "fixup_sparc_lox10", 0, 13, 0 },
{ "fixup_sparc_gotdata_hix22", 0, 0, 0 },
{ "fixup_sparc_gotdata_lox10", 0, 0, 0 },
{ "fixup_sparc_gotdata_op", 0, 0, 0 },
};
// clang-format on
// Fixup kinds from .reloc directive are like R_SPARC_NONE. They do
// not require any extra processing.

5
llvm/lib/Target/Sparc/MCTargetDesc/SparcELFObjectWriter.cpp
View File

@@ -98,6 +98,7 @@ unsigned SparcELFObjectWriter::getRelocType(MCContext &Ctx,
}
}
// clang-format off
switch(Fixup.getTargetKind()) {
default:
llvm_unreachable("Unimplemented fixup -> relocation");
@@ -127,10 +128,8 @@ unsigned SparcELFObjectWriter::getRelocType(MCContext &Ctx,
case Sparc::fixup_sparc_lm: return ELF::R_SPARC_LM22;
case Sparc::fixup_sparc_hix22: return ELF::R_SPARC_HIX22;
case Sparc::fixup_sparc_lox10: return ELF::R_SPARC_LOX10;
case Sparc::fixup_sparc_gotdata_hix22: return ELF::R_SPARC_GOTDATA_HIX22;
case Sparc::fixup_sparc_gotdata_lox10: return ELF::R_SPARC_GOTDATA_LOX10;
case Sparc::fixup_sparc_gotdata_op: return ELF::R_SPARC_GOTDATA_OP;
}
// clang-format on
return ELF::R_SPARC_NONE;
}

9
llvm/lib/Target/Sparc/MCTargetDesc/SparcFixupKinds.h
View File

@@ -13,6 +13,7 @@
namespace llvm {
namespace Sparc {
// clang-format off
enum Fixups {
// fixup_sparc_call30 - 30-bit PC relative relocation for call
fixup_sparc_call30 = FirstTargetFixupKind,
@@ -70,17 +71,11 @@ namespace llvm {
/// 13-bit fixup corresponding to %lox(foo)
fixup_sparc_lox10,
/// 22-bit fixup corresponding to %gdop_hix22(foo)
fixup_sparc_gotdata_hix22,
/// 13-bit fixup corresponding to %gdop_lox10(foo)
fixup_sparc_gotdata_lox10,
/// 32-bit fixup corresponding to %gdop(foo)
fixup_sparc_gotdata_op,
// Marker
LastTargetFixupKind,
NumTargetFixupKinds = LastTargetFixupKind - FirstTargetFixupKind
};
// clang-format on
}
}

16
llvm/lib/Target/Sparc/MCTargetDesc/SparcMCExpr.cpp
View File

@@ -80,9 +80,9 @@ StringRef SparcMCExpr::getSpecifierName(SparcMCExpr::Specifier S) {
case VK_TLS_LE_LOX10: return "tle_lox10";
case VK_HIX22: return "hix";
case VK_LOX10: return "lox";
case VK_GOTDATA_HIX22: return "gdop_hix22";
case VK_GOTDATA_LOX10: return "gdop_lox10";
case VK_GOTDATA_OP: return "gdop";
case VK_GOTDATA_OP_HIX22: return "gdop_hix22";
case VK_GOTDATA_OP_LOX10: return "gdop_lox10";
case VK_GOTDATA_OP: return "gdop";
}
// clang-format on
llvm_unreachable("Unhandled SparcMCExpr::Specifier");
@@ -126,8 +126,8 @@ SparcMCExpr::Specifier SparcMCExpr::parseSpecifier(StringRef name) {
.Case("tle_lox10", VK_TLS_LE_LOX10)
.Case("hix", VK_HIX22)
.Case("lox", VK_LOX10)
.Case("gdop_hix22", VK_GOTDATA_HIX22)
.Case("gdop_lox10", VK_GOTDATA_LOX10)
.Case("gdop_hix22", VK_GOTDATA_OP_HIX22)
.Case("gdop_lox10", VK_GOTDATA_OP_LOX10)
.Case("gdop", VK_GOTDATA_OP)
.Default(VK_None);
}
@@ -172,9 +172,9 @@ uint16_t SparcMCExpr::getFixupKind() const {
case VK_TLS_LE_LOX10: return ELF::R_SPARC_TLS_LE_LOX10;
case VK_HIX22: return Sparc::fixup_sparc_hix22;
case VK_LOX10: return Sparc::fixup_sparc_lox10;
case VK_GOTDATA_HIX22: return Sparc::fixup_sparc_gotdata_hix22;
case VK_GOTDATA_LOX10: return Sparc::fixup_sparc_gotdata_lox10;
case VK_GOTDATA_OP: return Sparc::fixup_sparc_gotdata_op;
case VK_GOTDATA_OP_HIX22: return ELF::R_SPARC_GOTDATA_OP_HIX22;
case VK_GOTDATA_OP_LOX10: return ELF::R_SPARC_GOTDATA_OP_LOX10;
case VK_GOTDATA_OP: return ELF::R_SPARC_GOTDATA_OP;
}
// clang-format on
}

4
llvm/lib/Target/Sparc/MCTargetDesc/SparcMCExpr.h
View File

@@ -61,8 +61,8 @@ public:
VK_TLS_LE_LOX10,
VK_HIX22,
VK_LOX10,
VK_GOTDATA_HIX22,
VK_GOTDATA_LOX10,
VK_GOTDATA_OP_HIX22,
VK_GOTDATA_OP_LOX10,
VK_GOTDATA_OP,
};

4
llvm/test/MC/Sparc/relocation-specifier.s
View File

@@ -63,8 +63,8 @@ sethi %lm(sym), %l0
# ASM-NEXT: ldx [%l7+%l1], %l2, %gdop(sym)
# OBJDUMP: R_SPARC_HIX22 sym
# OBJDUMP: R_SPARC_LOX10 sym
# OBJDUMP: R_SPARC_GOTDATA_HIX22 sym
# OBJDUMP: R_SPARC_GOTDATA_LOX10 sym
# OBJDUMP: R_SPARC_GOTDATA_OP_HIX22 sym
# OBJDUMP: R_SPARC_GOTDATA_OP_LOX10 sym
# OBJDUMP: R_SPARC_GOTDATA_OP sym
sethi %hix(sym), %g1
xor %g1, %lox(sym), %g1