bd6ed29f34
CFI can lead to some `relocation R_X86_64_32S out of range` errors when using thinlto. We have an instance of an `inline_bits` alias with a value of 0x8000008000000001 which cannot fit into a signed 32-bit reloc hence the error. This reloc is used because the instruction for reading the alias is `movq` which uses a signed 32-bit immediate. The proper instruction to use in this instance is `movabs` for the full 64-bit reloc. Under the kernel model, a signed 32-bit immediate was always used but if the target is a global with `absolue_symbol` we should reject the MOV64ri32. The pattern matching logic will eventually lead to a match for MOV64ri which emits the `movabs`.
35 lines
1.0 KiB
LLVM
35 lines
1.0 KiB
LLVM
; RUN: llc --code-model=kernel < %s -asm-verbose=0 | FileCheck %s
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target triple = "x86_64-unknown-linux-gnu"
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; CHECK-LABEL: func_no_abs_sym
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define i64 @func_no_abs_sym() nounwind {
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; CHECK: movq $no_abs_sym, %rax
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%1 = ptrtoint ptr @no_abs_sym to i64
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ret i64 %1
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}
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; CHECK-LABEL: func_abs_sym
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define i64 @func_abs_sym() nounwind {
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; CHECK: movabsq $abs_sym, %rax
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%1 = ptrtoint ptr @abs_sym to i64
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ret i64 %1
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}
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; CHECK-LABEL: func_abs_sym_in_range
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define i64 @func_abs_sym_in_range() nounwind {
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;; The absolute_symbol range fits in 32 bits but we still use movabs
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;; since there's no benefit to using the sign extending instruction
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;; with absolute symbols.
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; CHECK: movabsq $abs_sym_in_range, %rax
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%1 = ptrtoint ptr @abs_sym_in_range to i64
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ret i64 %1
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}
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@no_abs_sym = external hidden global [0 x i8]
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@abs_sym = external hidden global [0 x i8], !absolute_symbol !0
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@abs_sym_in_range = external hidden global [0 x i8], !absolute_symbol !1
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!0 = !{i64 -1, i64 -1} ;; Full range
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!1 = !{i64 -2147483648, i64 2147483648} ;; In range
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