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Perform symbol binding for .symver versioned symbols
Summary: In a .symver assembler directive like: .symver name, name2@@nodename "name2@@nodename" should get the same symbol binding as "name". While the ELF object writer is updating the symbol binding for .symver aliases before emitting the object file, not doing so when the module inline assembly is handled by the RecordStreamer is causing the wrong behavior in *LTO mode. E.g. when "name" is global, "name2@@nodename" must also be marked as global. Otherwise, the symbol is skipped when iterating over the LTO InputFile symbols (InputFile::Symbol::shouldSkip). So, for example, when performing any *LTO via the gold-plugin, the versioned symbol definition is not recorded by the plugin and passed back to the linker. If the object was in an archive, and there were no other symbols needed from that object, the object would not be included in the final link and references to the versioned symbol are undefined. The llvm-lto2 tests added will give an error about an unused symbol resolution without the fix. Reviewers: rafael, pcc Reviewed By: pcc Subscribers: mehdi_amini, llvm-commits Differential Revision: https://reviews.llvm.org/D30485 llvm-svn: 297332
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Original file line number | Diff line number | Diff line change |
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@@ -1,16 +1,47 @@ | ||
; RUN: llvm-as < %s >%t1 | ||
; RUN: llvm-lto -o %t2 %t1 | ||
; RUN: llvm-lto -exported-symbol=io_cancel_0_4 -exported-symbol=io_cancel_weak_0_4 -exported-symbol=foo -o %t2 %t1 | ||
; RUN: llvm-nm %t2 | FileCheck %s | ||
; RUN: llvm-lto2 -r %t1,io_cancel_0_4,plx -r %t1,io_cancel_0_4,plx -r %t1,io_cancel_local_0_4,plx -r %t1,io_cancel_weak_0_4,plx -r %t1,io_cancel_weak_0_4,plx -r %t1,io_cancel@@LIBAIO_0.4,plx -r %t1,io_cancel_weak@@LIBAIO_0.4,plx -r %t1,io_cancel_weak@@LIBAIO_0.4.1,plx -r %t1,foo,plx -r %t1,foo,plx -r %t1,foo@@VER1,plx -o %t3 %t1 -save-temps | ||
; RUN: llvm-nm %t3.0 | FileCheck %s | ||
; RUN: llvm-dis %t3.0.2.internalize.bc -o - | FileCheck %s --check-prefix=INTERN | ||
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" | ||
target triple = "x86_64-unknown-linux-gnu" | ||
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module asm ".symver io_cancel_0_4,io_cancel@@LIBAIO_0.4" | ||
module asm ".symver io_cancel_local_0_4,io_cancel_local@@LIBAIO_0.4" | ||
module asm ".symver io_cancel_weak_0_4,io_cancel_weak@@LIBAIO_0.4" | ||
; Ensure we handle case of same aliasee with two version aliases. | ||
module asm ".symver io_cancel_weak_0_4,io_cancel_weak@@LIBAIO_0.4.1" | ||
module asm ".symver foo,foo@@VER1" | ||
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; Local values used in inline assembly must be specified on the | ||
; llvm.compiler.used so they aren't incorrectly DCE'd during module linking. | ||
@llvm.compiler.used = appending global [1 x i8*] [i8* bitcast (i32 ()* @io_cancel_local_0_4 to i8*)], section "llvm.metadata" | ||
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; Even without -exported-symbol, io_cancel_0_4 should be noticed by LTOModule's | ||
; RecordStreamer, so it shouldn't get eliminated. However, the object file will | ||
; contain the aliased symver as well as the original. | ||
define i32 @io_cancel_0_4() { | ||
; CHECK: io_cancel@@LIBAIO_0.4 | ||
; CHECK: io_cancel_0_4 | ||
; CHECK-DAG: T io_cancel@@LIBAIO_0.4 | ||
; CHECK-DAG: T io_cancel_0_4 | ||
ret i32 0 | ||
} | ||
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define internal i32 @io_cancel_local_0_4() { | ||
; INTERN: llvm.compiler.used {{.*}} @io_cancel_local_0_4 | ||
; INTERN: define internal i32 @io_cancel_local_0_4() | ||
; CHECK-DAG: t io_cancel_local@@LIBAIO_0.4 | ||
; CHECK-DAG: t io_cancel_local_0_4 | ||
ret i32 0 | ||
} | ||
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define weak i32 @io_cancel_weak_0_4() { | ||
; CHECK-DAG: W io_cancel_weak@@LIBAIO_0.4 | ||
; CHECK-DAG: W io_cancel_weak@@LIBAIO_0.4.1 | ||
; CHECK-DAG: W io_cancel_weak_0_4 | ||
ret i32 0 | ||
} | ||
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define i32 @"\01foo"() { | ||
; CHECK-DAG: T foo@@VER1 | ||
; CHECK-DAG: T foo | ||
ret i32 0 | ||
} |
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,30 @@ | ||
; Test to ensure symbol binding works correctly for symver directives, | ||
; when the aliased symbols are defined in inline assembly, including | ||
; cases when the symbol attributes are provided after the .symver | ||
; directive. | ||
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; RUN: llvm-as < %s >%t1 | ||
; RUN: llvm-lto -o %t2 %t1 | ||
; RUN: llvm-nm %t2 | FileCheck %s | ||
; RUN: llvm-lto2 -r %t1,_start,plx -r %t1,_start3,plx -r %t1,foo@@SOME_VERSION -r %t1,foo@SOME_VERSION3 -o %t3 %t1 -save-temps | ||
; RUN: llvm-nm %t3.0 | FileCheck %s | ||
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" | ||
target triple = "x86_64-unknown-linux-gnu" | ||
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module asm ".global _start" | ||
module asm "_start:" | ||
module asm "_start2:" | ||
module asm "_start3:" | ||
module asm ".symver _start, foo@@SOME_VERSION" | ||
module asm ".symver _start2, foo@SOME_VERSION2" | ||
module asm ".symver _start3, foo@SOME_VERSION3" | ||
module asm ".local _start2" | ||
module asm ".weak _start3" | ||
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; CHECK-DAG: T _start | ||
; CHECK-DAG: t _start2 | ||
; CHECK-DAG: W _start3 | ||
; CHECK-DAG: T foo@@SOME_VERSION | ||
; CHECK-DAG: t foo@SOME_VERSION2 | ||
; CHECK-DAG: W foo@SOME_VERSION3 |