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[JITLink][AArch32] Add support for ELF::R_ARM_THM_MOV{W_PREL_NC,T_PREL} #70364

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Merged
merged 2 commits into from
Nov 9, 2023
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[JITLink][AArch32] Add support for ELF::R_ARM_THM_MOV{W_PREL_NC,T_PREL} #70364

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5cae6a9
[JITLink][AArch32] Add support for ELF::R_ARM_THM_MOV{W_PREL_NC,T_PREL}
eymay Oct 26, 2023
56aa89f
remove nextpc
eymay Nov 8, 2023
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10 changes: 9 additions & 1 deletion llvm/include/llvm/ExecutionEngine/JITLink/aarch32.h
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Original file line number Diff line number Diff line change
Expand Up @@ -89,7 +89,15 @@ enum EdgeKind_aarch32 : Edge::Kind {
/// Write immediate value to the top halfword of the destination register
Thumb_MovtAbs,

LastThumbRelocation = Thumb_MovtAbs,
/// Write PC-relative immediate value to the lower halfword of the destination
/// register
Thumb_MovwPrelNC,

/// Write PC-relative immediate value to the top halfword of the destination
/// register
Thumb_MovtPrel,

LastThumbRelocation = Thumb_MovtPrel,
};

/// Flags enum for AArch32-specific symbol properties
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8 changes: 8 additions & 0 deletions llvm/lib/ExecutionEngine/JITLink/ELF_aarch32.cpp
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Expand Up @@ -53,6 +53,10 @@ Expected<aarch32::EdgeKind_aarch32> getJITLinkEdgeKind(uint32_t ELFType) {
return aarch32::Thumb_MovwAbsNC;
case ELF::R_ARM_THM_MOVT_ABS:
return aarch32::Thumb_MovtAbs;
case ELF::R_ARM_THM_MOVW_PREL_NC:
return aarch32::Thumb_MovwPrelNC;
case ELF::R_ARM_THM_MOVT_PREL:
return aarch32::Thumb_MovtPrel;
}

return make_error<JITLinkError>(
Expand Down Expand Up @@ -83,6 +87,10 @@ Expected<uint32_t> getELFRelocationType(Edge::Kind Kind) {
return ELF::R_ARM_THM_MOVW_ABS_NC;
case aarch32::Thumb_MovtAbs:
return ELF::R_ARM_THM_MOVT_ABS;
case aarch32::Thumb_MovwPrelNC:
return ELF::R_ARM_THM_MOVW_PREL_NC;
case aarch32::Thumb_MovtPrel:
return ELF::R_ARM_THM_MOVT_PREL;
}

return make_error<JITLinkError>(formatv("Invalid aarch32 edge {0:d}: ",
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18 changes: 18 additions & 0 deletions llvm/lib/ExecutionEngine/JITLink/aarch32.cpp
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Expand Up @@ -377,12 +377,14 @@ Expected<int64_t> readAddendThumb(LinkGraph &G, Block &B, const Edge &E,
: decodeImmBT4BlT1BlxT2(R.Hi, R.Lo);

case Thumb_MovwAbsNC:
case Thumb_MovwPrelNC:
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We were talking about the opcode checks and duplication in both, code and constants. I've been working on a patch to compensate for it here: #71649 With that the asymmetry in opcode checks will go away. I think we can land this as is.

if (!checkOpcode<Thumb_MovwAbsNC>(R))
return makeUnexpectedOpcodeError(G, R, Kind);
// Initial addend is interpreted as a signed value
return SignExtend64<16>(decodeImmMovtT1MovwT3(R.Hi, R.Lo));

case Thumb_MovtAbs:
case Thumb_MovtPrel:
if (!checkOpcode<Thumb_MovtAbs>(R))
return makeUnexpectedOpcodeError(G, R, Kind);
// Initial addend is interpreted as a signed value
Expand Down Expand Up @@ -610,6 +612,20 @@ Error applyFixupThumb(LinkGraph &G, Block &B, const Edge &E,
writeImmediate<Thumb_MovtAbs>(R, encodeImmMovtT1MovwT3(Value));
return Error::success();
}
case Thumb_MovwPrelNC: {
if (!checkOpcode<Thumb_MovwAbsNC>(R))
return makeUnexpectedOpcodeError(G, R, Kind);
uint16_t Value = ((TargetAddress + Addend - FixupAddress) & 0xffff);
writeImmediate<Thumb_MovwAbsNC>(R, encodeImmMovtT1MovwT3(Value));
return Error::success();
}
case Thumb_MovtPrel: {
if (!checkOpcode<Thumb_MovtAbs>(R))
return makeUnexpectedOpcodeError(G, R, Kind);
uint16_t Value = (((TargetAddress + Addend - FixupAddress) >> 16) & 0xffff);
writeImmediate<Thumb_MovtAbs>(R, encodeImmMovtT1MovwT3(Value));
return Error::success();
}

default:
return make_error<JITLinkError>(
Expand Down Expand Up @@ -659,6 +675,8 @@ const char *getEdgeKindName(Edge::Kind K) {
KIND_NAME_CASE(Thumb_Jump24)
KIND_NAME_CASE(Thumb_MovwAbsNC)
KIND_NAME_CASE(Thumb_MovtAbs)
KIND_NAME_CASE(Thumb_MovwPrelNC)
KIND_NAME_CASE(Thumb_MovtPrel)
default:
return getGenericEdgeKindName(K);
}
Expand Down
31 changes: 30 additions & 1 deletion llvm/test/ExecutionEngine/JITLink/AArch32/ELF_static_thumb_reloc.s
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Expand Up @@ -2,7 +2,8 @@
# RUN: llvm-objdump -r %t.o | FileCheck --check-prefix=CHECK-TYPE %s
# RUN: llvm-objdump --disassemble %t.o | FileCheck --check-prefix=CHECK-INSTR %s
# RUN: llvm-jitlink -noexec -slab-address 0x76ff0000 -slab-allocate 10Kb \
# RUN: -slab-page-size 4096 -show-entry-es -check %s %t.o
# RUN: -slab-page-size 4096 -abs external_func=0x76bbe880 \
# RUN: -check %s %t.o


.text
Expand Down Expand Up @@ -95,6 +96,34 @@ data_symbol:

.text

# CHECK-TYPE: {{[0-9a-f]+}} R_ARM_THM_MOVW_PREL_NC external_func
# CHECK-INSTR: 00000014 <movw_prel>:
# CHECK-INSTR: 14: f240 0000 movw r0, #0x0
# jitlink-check: decode_operand(movw_prel, 1) = \
# jitlink-check: ((external_func - movw_prel)&0x0000ffff)
.globl movw_prel
.type movw_prel,%function
.p2align 1
.code 16
.thumb_func
movw_prel:
movw r0, :lower16:external_func - .
.size movw_prel, .-movw_prel

# CHECK-TYPE: {{[0-9a-f]+}} R_ARM_THM_MOVT_PREL external_func
# CHECK-INSTR: 00000018 <movt_prel>:
# CHECK-INSTR: 18: f2c0 0000 movt r0, #0x0
# jitlink-check: decode_operand(movt_prel, 2) = \
# jitlink-check: ((external_func - movt_prel)&0xffff0000>>16)
.globl movt_prel
.type movt_prel,%function
.p2align 1
.code 16
.thumb_func
movt_prel:
movt r0, :upper16:external_func - .
.size movt_prel, .-movt_prel

# Empty main function for jitlink to be happy
.globl main
.type main,%function
Expand Down