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[RuntimeDyldChecker][AArch32] Add a PC offset to next_PC for ARM targets #91746

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Merged
merged 6 commits into from
May 28, 2024
Merged

[RuntimeDyldChecker][AArch32] Add a PC offset to next_PC for ARM targets #91746

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a5489fc
[RuntimeDyldChecker][AArch32] Add a PC offset to next_PC for ARM targets
eymay May 10, 2024
8b06eca
Simplify the PC offset declaration
eymay May 12, 2024
164b5e2
Teach evalNextPC to decode addition expression with a symbol
eymay May 12, 2024
83590c4
Revert expression decoding in next_pc
eymay May 24, 2024
1391f04
Refactor test Assembly for simpler checking
eymay May 24, 2024
d50e05e
Replace the ARM PC constant with next_pc in got test
eymay May 24, 2024
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8 changes: 7 additions & 1 deletion llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp
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Expand Up @@ -369,7 +369,13 @@ class RuntimeDyldCheckerExprEval {
uint64_t SymbolAddr = PCtx.IsInsideLoad
? Checker.getSymbolLocalAddr(Symbol)
: Checker.getSymbolRemoteAddr(Symbol);
uint64_t NextPC = SymbolAddr + InstSize;

// ARM PC offset is 8 instead of 4, because it accounts for an additional
// prefetch instruction that increments PC even though it is implicit.
auto TT = Checker.getTripleForSymbol(Checker.getTargetFlag(Symbol));
uint64_t PCOffset = TT.getArch() == Triple::ArchType::arm ? 4 : 0;

uint64_t NextPC = SymbolAddr + InstSize + PCOffset;

return std::make_pair(EvalResult(NextPC), RemainingExpr);
}
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38 changes: 22 additions & 16 deletions llvm/test/ExecutionEngine/JITLink/AArch32/ELF_relocations_arm.s
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Expand Up @@ -23,23 +23,29 @@
.syntax unified

# CHECK-TYPE: {{[0-9a-f]+}} R_ARM_CALL call_target_arm
# CHECK-INSTR: 00000000 <call_site>:
# CHECK-INSTR: 00000000 <call_site_a2a>:
# CHECK-INSTR: 0: ebfffffe bl
# CHECK-INSTR: 4: ebfffffe bl
# CHECK-INSTR: 0000000c <call_target_arm>
# CHECK-INSTR: 00000010 <call_target_thumb>
# ARM branch offset is 8, because it accounts for an additional prefetch
# instruction that increments PC even though it is implicit
# jitlink-check: decode_operand(call_site + 0, 0) = call_target_arm - (call_site + 8)
# jitlink-check: decode_operand(call_site + 4, 0) = call_target_thumb - (call_site + 12)
.globl call_site
.type call_site,%function
# CHECK-INSTR: 00000008 <call_site_a2t>:
# CHECK-INSTR: 8: ebfffffe bl
# CHECK-INSTR: 00000010 <call_target_arm>
# CHECK-INSTR: 00000014 <call_target_thumb>
# jitlink-check: decode_operand(call_site_a2a, 0) = call_target_arm - next_pc(call_site_a2a)
# jitlink-check: decode_operand(call_site_a2t, 0) = call_target_thumb - next_pc(call_site_a2t)
.globl call_site_a2a
.type call_site_a2a, %function
.p2align 2
call_site:
call_site_a2a:
bl call_target_arm
bx lr
.size call_site_a2a, .-call_site_a2a

.globl call_site_a2t
.type call_site_a2t,%function
.p2align 2
call_site_a2t:
bl call_target_thumb
bx lr
.size call_site, .-call_site
.size call_site_a2t, .-call_site_a2t

.globl call_target_arm
.type call_target_arm,%function
Expand All @@ -59,10 +65,10 @@ call_target_thumb:
.code 32

# CHECK-TYPE: {{[0-9a-f]+}} R_ARM_JUMP24 jump24_target
# CHECK-INSTR: 00000014 <jump24_site>:
# CHECK-INSTR: 14: eafffffe b
# CHECK-INSTR: 00000018 <jump24_target>
# jitlink-check: decode_operand(jump24_site, 0) = jump24_target - (jump24_site + 8)
# CHECK-INSTR: 00000018 <jump24_site>:
# CHECK-INSTR: 18: eafffffe b
# CHECK-INSTR: 0000001c <jump24_target>
# jitlink-check: decode_operand(jump24_site, 0) = jump24_target - next_pc(jump24_site)
.globl jump24_site
.type jump24_site,%function
.p2align 2
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2 changes: 1 addition & 1 deletion llvm/test/ExecutionEngine/JITLink/AArch32/ELF_relocations_data.s
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Expand Up @@ -50,7 +50,7 @@ target1_abs32:
# The +12 accounts for the ARM branch offset (8) and the .LPC offset (4), which
# is stored as initial addend inline.
# FIXME: We shouldn't need to substract the 64-bit sign-extension manually.
# jitlink-check: *{4}got_prel_offset = got_addr(out.o, target) - (got_prel + 12) - 0xffffffff00000000
# jitlink-check: *{4}got_prel_offset = got_addr(out.o, target) - (next_pc(got_prel) + 4) - 0xffffffff00000000
.globl got_prel
.type got_prel,%function
.p2align 2
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2 changes: 1 addition & 1 deletion llvm/test/ExecutionEngine/JITLink/AArch32/ELF_relocations_thumbv6m.s
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Expand Up @@ -30,7 +30,7 @@
# CHECK-INSTR: f7ff fffe bl
# We decode the operand with index 2, because bl generates two leading implicit
# predicate operands that we have to skip in order to decode the call_target operand
# jitlink-check: decode_operand(call_site, 2) = call_target_thumb - (call_site + 4)
# jitlink-check: decode_operand(call_site, 2) = call_target_thumb - next_pc(call_site)
.globl call_site
.type call_site,%function
.p2align 1
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4 changes: 2 additions & 2 deletions llvm/test/ExecutionEngine/JITLink/AArch32/ELF_stubs_arm.s
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Expand Up @@ -27,7 +27,7 @@
# hard-code it in the immediate field.

# The external function ext will return to the caller directly.
# jitlink-check: decode_operand(test_arm_jump, 0) = stub_addr(out.o, ext) - (test_arm_jump + 8)
# jitlink-check: decode_operand(test_arm_jump, 0) = stub_addr(out.o, ext) - next_pc(test_arm_jump)
.globl test_arm_jump
.type test_arm_jump,%function
.p2align 2
Expand All @@ -38,7 +38,7 @@ test_arm_jump:
# The branch-with-link sets the LR register so that the external function ext
# returns to us. We have to save the register (push) and return to main manually
# (pop). This adds the +4 offset for the bl instruction we decode:
# jitlink-check: decode_operand(test_arm_call + 4, 0) = stub_addr(out.o, ext) - (test_arm_call + 8) - 4
# jitlink-check: decode_operand(test_arm_call + 4, 0) = stub_addr(out.o, ext) - next_pc(test_arm_call) - 4
.globl test_arm_call
.type test_arm_call,%function
.p2align 2
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4 changes: 2 additions & 2 deletions llvm/test/ExecutionEngine/JITLink/AArch32/ELF_stubs_multi.s
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Expand Up @@ -13,7 +13,7 @@
# ascending size (because the default memory manager lays out blocks by size).

# Thumb relocation site emits thumb stub
# jitlink-check: decode_operand(test_stub_thumb, 0) = stub_addr(out.o, ext, thumb) - (test_stub_thumb + 4)
# jitlink-check: decode_operand(test_stub_thumb, 0) = stub_addr(out.o, ext, thumb) - next_pc(test_stub_thumb)
.globl test_stub_thumb
.type test_stub_thumb,%function
.p2align 1
Expand All @@ -24,7 +24,7 @@ test_stub_thumb:
.size test_stub_thumb, .-test_stub_thumb

# Arm relocation site emits arm stub
# jitlink-check: decode_operand(test_stub_arm, 0) = stub_addr(out.o, ext, arm) - (test_stub_arm + 8)
# jitlink-check: decode_operand(test_stub_arm, 0) = stub_addr(out.o, ext, arm) - next_pc(test_stub_arm)
.globl test_stub_arm
.type test_stub_arm,%function
.p2align 2
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