[lld] e941fe5 - [lld-macho] Fix symbol relocs handling for compact unwind's functionAddress
Jez Ng via llvm-commits
llvm-commits at lists.llvm.org
Thu Nov 11 19:53:51 PST 2021
Author: Jez Ng
Date: 2021-11-11T22:53:35-05:00
New Revision: e941fe506114569410ec8c77e600cddd5a77559d
URL: https://github.com/llvm/llvm-project/commit/e941fe506114569410ec8c77e600cddd5a77559d
DIFF: https://github.com/llvm/llvm-project/commit/e941fe506114569410ec8c77e600cddd5a77559d.diff
LOG: [lld-macho] Fix symbol relocs handling for compact unwind's functionAddress
Clang seems to emit all functionAddress relocs as section relocs, but
`ld -r` can turn those relocs into symbol ones. It turns out that we
weren't handling that case correctly when the symbol was a weak def
whose definition did not prevail.
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D113702
Added:
Modified:
lld/MachO/InputFiles.cpp
lld/test/MachO/weak-definition-gc.s
Removed:
################################################################################
diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
index 361f24a8531b6..33decc0aad795 100644
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -910,6 +910,12 @@ void ObjFile::registerCompactUnwind() {
continue;
uint64_t add = r.addend;
if (auto *sym = cast_or_null<Defined>(r.referent.dyn_cast<Symbol *>())) {
+ // Check whether the symbol defined in this file is the prevailing one.
+ // Skip if it is e.g. a weak def that didn't prevail.
+ if (sym->getFile() != this) {
+ ++it;
+ continue;
+ }
add += sym->value;
referentIsec = cast<ConcatInputSection>(sym->isec);
} else {
diff --git a/lld/test/MachO/weak-definition-gc.s b/lld/test/MachO/weak-definition-gc.s
index 819f33faa4508..e1d5cb44ddb0e 100644
--- a/lld/test/MachO/weak-definition-gc.s
+++ b/lld/test/MachO/weak-definition-gc.s
@@ -30,19 +30,29 @@
## Test that omitted weak symbols don't add entries to the compact unwind table.
# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin19.0.0 %t/weak-sub-lsda.s -o %t/weak-sub-lsda.o
# RUN: %lld -dylib -lc++ -o %t/out.dylib %t/weak-sub-lsda.o %t/weak-sub-lsda.o
-# RUN: llvm-objdump --macho --unwind-info --syms %t/out.dylib | FileCheck %s --check-prefix=UNWIND -D#%x,BASE=0
-
-# UNWIND: SYMBOL TABLE:
-# UNWIND-DAG: [[#%x,FOO:]] w F __TEXT,__text _foo
-# UNWIND-NOT: __TEXT,__text _foo
-
-# UNWIND: Contents of __unwind_info section:
-# UNWIND: LSDA descriptors:
-# UNWIND: [0]: function offset=0x[[#%.8x,FOO-BASE]]
-# UNWIND-NOT: [1]:
-# UNWIND: Second level indices:
-# UNWIND-DAG: [0]: function offset=0x[[#%.8x,FOO-BASE]]
-# UNWIND-NOT: [1]:
+# RUN: llvm-objdump --macho --unwind-info --syms %t/out.dylib | FileCheck %s --check-prefix=ONE-UNWIND
+# RUN: %lld -dylib -lc++ -o %t/out.dylib %t/weak-sub.o %t/weak-sub-lsda.o
+# RUN: llvm-objdump --macho --unwind-info --syms %t/out.dylib | FileCheck %s --check-prefix=NO-UNWIND
+# RUN: yaml2obj %t/weak-sub-lsda-r.yaml -o %t/weak-sub-lsda-r.o
+# RUN: %lld -dylib -lc++ -o %t/out.dylib %t/weak-sub.o %t/weak-sub-lsda-r.o
+# RUN: llvm-objdump --macho --unwind-info --syms %t/out.dylib | FileCheck %s --check-prefix=NO-UNWIND
+
+# ONE-UNWIND: SYMBOL TABLE:
+# ONE-UNWIND-DAG: [[#%x,FOO:]] w F __TEXT,__text _foo
+# ONE-UNWIND-NOT: __TEXT,__text _foo
+
+# ONE-UNWIND: Contents of __unwind_info section:
+# ONE-UNWIND: LSDA descriptors:
+# ONE-UNWIND: [0]: function offset=0x[[#%.8x,FOO]]
+# ONE-UNWIND-NOT: [1]:
+# ONE-UNWIND: Second level indices:
+# ONE-UNWIND-DAG: [0]: function offset=0x[[#%.8x,FOO]]
+# ONE-UNWIND-NOT: [1]:
+
+# NO-UNWIND: SYMBOL TABLE:
+# NO-UNWIND-DAG: [[#%x,FOO:]] w F __TEXT,__text _foo
+# NO-UNWIND-NOT: __TEXT,__text _foo
+# NO-UNWIND-NOT: Contents of __unwind_info section:
## Test interaction with .alt_entry
## FIXME: ld64 manages to strip both one copy of _foo and _bar each.
@@ -246,3 +256,220 @@ _foo:
retq
.subsections_via_symbols
+
+#--- weak-sub-lsda-r.yaml
+## This was generated from compiling weak-sub-lsda.s above at rev a2404f11c77e
+## and then running it through `ld -r`. This converts a number of unwind-related
+## relocations from section- to symbol-based ones.
+--- !mach-o
+FileHeader:
+ magic: 0xFEEDFACF
+ cputype: 0x1000007
+ cpusubtype: 0x3
+ filetype: 0x1
+ ncmds: 2
+ sizeofcmds: 464
+ flags: 0x2000
+ reserved: 0x0
+LoadCommands:
+ - cmd: LC_SEGMENT_64
+ cmdsize: 392
+ segname: ''
+ vmaddr: 0
+ vmsize: 152
+ fileoff: 528
+ filesize: 152
+ maxprot: 7
+ initprot: 7
+ nsects: 3
+ flags: 0
+ Sections:
+ - sectname: __text
+ segname: __TEXT
+ addr: 0x0
+ size: 6
+ offset: 0x210
+ align: 0
+ reloff: 0x0
+ nreloc: 0
+ flags: 0x80000400
+ reserved1: 0x0
+ reserved2: 0x0
+ reserved3: 0x0
+ content: 554889E55DC3
+ - sectname: __gcc_except_tab
+ segname: __TEXT
+ addr: 0x6
+ size: 32
+ offset: 0x216
+ align: 0
+ reloff: 0x0
+ nreloc: 0
+ flags: 0x0
+ reserved1: 0x0
+ reserved2: 0x0
+ reserved3: 0x0
+ content: '0000000000000000000000000000000000000000000000000000000000000000'
+ - sectname: __eh_frame
+ segname: __TEXT
+ addr: 0x28
+ size: 80
+ offset: 0x238
+ align: 3
+ reloff: 0x2A8
+ nreloc: 7
+ flags: 0x0
+ reserved1: 0x0
+ reserved2: 0x0
+ reserved3: 0x0
+ content: 1C00000000000000017A504C5200017810079B0400000010100C0708900100002C00000004000000F8FFFFFFFFFFFFFF060000000000000008E7FFFFFFFFFFFFFF410E800111067A430D060000000000
+ relocations:
+ - address: 0x13
+ symbolnum: 5
+ pcrel: true
+ length: 2
+ extern: true
+ type: 4
+ scattered: false
+ value: 0
+ - address: 0x24
+ symbolnum: 2
+ pcrel: false
+ length: 2
+ extern: true
+ type: 5
+ scattered: false
+ value: 0
+ - address: 0x24
+ symbolnum: 3
+ pcrel: false
+ length: 2
+ extern: true
+ type: 0
+ scattered: false
+ value: 0
+ - address: 0x28
+ symbolnum: 3
+ pcrel: false
+ length: 3
+ extern: true
+ type: 5
+ scattered: false
+ value: 0
+ - address: 0x28
+ symbolnum: 4
+ pcrel: false
+ length: 3
+ extern: true
+ type: 0
+ scattered: false
+ value: 0
+ - address: 0x39
+ symbolnum: 3
+ pcrel: false
+ length: 3
+ extern: true
+ type: 5
+ scattered: false
+ value: 0
+ - address: 0x39
+ symbolnum: 1
+ pcrel: false
+ length: 3
+ extern: true
+ type: 0
+ scattered: false
+ value: 0
+ - sectname: __compact_unwind
+ segname: __LD
+ addr: 0x78
+ size: 32
+ offset: 0x288
+ align: 3
+ reloff: 0x2E0
+ nreloc: 4
+ flags: 0x2000000
+ reserved1: 0x0
+ reserved2: 0x0
+ reserved3: 0x0
+ content: '0000000000000000060000000000004100000000000000000000000000000000'
+ relocations:
+ - address: 0x0
+ symbolnum: 4
+ pcrel: false
+ length: 3
+ extern: true
+ type: 0
+ scattered: false
+ value: 0
+ - address: 0x18
+ symbolnum: 1
+ pcrel: false
+ length: 3
+ extern: true
+ type: 0
+ scattered: false
+ value: 0
+ - address: 0x10
+ symbolnum: 5
+ pcrel: false
+ length: 3
+ extern: true
+ type: 0
+ scattered: false
+ value: 0
+ - address: 0x18
+ symbolnum: 1
+ pcrel: false
+ length: 3
+ extern: true
+ type: 0
+ scattered: false
+ value: 0
+ - cmd: LC_SYMTAB
+ cmdsize: 24
+ symoff: 768
+ nsyms: 6
+ stroff: 864
+ strsize: 57
+LinkEditData:
+ NameList:
+ - n_strx: 29
+ n_type: 0xE
+ n_sect: 2
+ n_desc: 0
+ n_value: 6
+ - n_strx: 34
+ n_type: 0xE
+ n_sect: 2
+ n_desc: 0
+ n_value: 22
+ - n_strx: 39
+ n_type: 0xE
+ n_sect: 3
+ n_desc: 0
+ n_value: 40
+ - n_strx: 49
+ n_type: 0xE
+ n_sect: 3
+ n_desc: 0
+ n_value: 72
+ - n_strx: 2
+ n_type: 0xF
+ n_sect: 1
+ n_desc: 128
+ n_value: 0
+ - n_strx: 7
+ n_type: 0x1
+ n_sect: 0
+ n_desc: 0
+ n_value: 0
+ StringTable:
+ - ' '
+ - _foo
+ - ___gxx_personality_v0
+ - l001
+ - l002
+ - EH_Frame1
+ - func.eh
+...
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