[lld] 44361e5 - [ELF] Add --export-dynamic-symbol-list
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 3 09:01:09 PDT 2021
Author: Fangrui Song
Date: 2021-08-03T09:01:03-07:00
New Revision: 44361e5b90986ebe64c2263cefe504bf9b170eac
URL: https://github.com/llvm/llvm-project/commit/44361e5b90986ebe64c2263cefe504bf9b170eac
DIFF: https://github.com/llvm/llvm-project/commit/44361e5b90986ebe64c2263cefe504bf9b170eac.diff
LOG: [ELF] Add --export-dynamic-symbol-list
This is available in GNU ld 2.35 and can be seen as a shortcut for multiple
--export-dynamic-symbol, or a --dynamic-list variant without the symbolic intention.
In the long term, this option probably should be preferred over --dynamic-list.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D107317
Added:
Modified:
lld/ELF/Driver.cpp
lld/ELF/Options.td
lld/docs/ReleaseNotes.rst
lld/docs/ld.lld.1
lld/test/ELF/export-dynamic-symbol.s
Removed:
################################################################################
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 91e7df21a60ad..56f3adc80e58a 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -1379,7 +1379,8 @@ static void readConfigs(opt::InputArgList &args) {
// symbols not specified by --dynamic-list are non-preemptible.
config->symbolic =
config->bsymbolic == BsymbolicKind::All || args.hasArg(OPT_dynamic_list);
- for (auto *arg : args.filtered(OPT_dynamic_list))
+ for (auto *arg :
+ args.filtered(OPT_dynamic_list, OPT_export_dynamic_symbol_list))
if (Optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
readDynamicList(*buffer);
diff --git a/lld/ELF/Options.td b/lld/ELF/Options.td
index f0e4c11b79ebd..9667d859a6b42 100644
--- a/lld/ELF/Options.td
+++ b/lld/ELF/Options.td
@@ -156,10 +156,8 @@ def discard_none: F<"discard-none">,
defm dynamic_linker: Eq<"dynamic-linker", "Which dynamic linker to use">;
defm dynamic_list : Eq<"dynamic-list",
- "Read a list of dynamic symbols. (executable) Put matched non-local defined"
- "symbols to the dynamic symbol table. (shared object) References to matched"
- "non-local STV_DEFAULT symbols shouldn't be bound to definitions within the "
- "shared object. Implies -Bsymbolic but does not set DF_SYMBOLIC">,
+ "Similar to --export-dynamic-symbol-list. When creating a shared object, "
+ "this additionally implies -Bsymbolic but does not set DF_SYMBOLIC">,
MetaVarName<"<file>">;
def eb: F<"EB">, HelpText<"Select the big-endian format in OUTPUT_FORMAT">;
@@ -209,6 +207,10 @@ defm export_dynamic_symbol : EEq<"export-dynamic-symbol",
"Does not imply -Bsymbolic.">,
MetaVarName<"glob">;
+defm export_dynamic_symbol_list : EEq<"export-dynamic-symbol-list",
+ "Read a list of dynamic symbol patterns. Apply --export-dynamic-symbol on each pattern">,
+ MetaVarName<"file">;
+
defm fatal_warnings: B<"fatal-warnings",
"Treat warnings as errors",
"Do not treat warnings as errors (default)">;
diff --git a/lld/docs/ReleaseNotes.rst b/lld/docs/ReleaseNotes.rst
index d21299f7e5dab..68d6f6a0dd588 100644
--- a/lld/docs/ReleaseNotes.rst
+++ b/lld/docs/ReleaseNotes.rst
@@ -24,8 +24,8 @@ Non-comprehensive list of changes in this release
ELF Improvements
----------------
-* ``-Bsymbolic-non-weak-functions`` has been added as a ``STB_GLOBAL`` subset of ``-Bsymbolic-functions``.
- (`D102570 <https://reviews.llvm.org/D102570>`_)
+* ``--export-dynamic-symbol-list`` has been added.
+ (`D107317 <https://reviews.llvm.org/D107317>`_)
Breaking changes
----------------
diff --git a/lld/docs/ld.lld.1 b/lld/docs/ld.lld.1
index bd67e58daa4dd..cce00837c5429 100644
--- a/lld/docs/ld.lld.1
+++ b/lld/docs/ld.lld.1
@@ -167,10 +167,9 @@ Specify the dynamic linker to be used for a dynamically linked executable.
This is recorded in an ELF segment of type
.Dv PT_INTERP .
.It Fl -dynamic-list Ns = Ns Ar file
-Read a list of dynamic symbols from
-.Ar file .
-(executable) Put matched non-local defined symbols to the dynamic symbol table.
-(shared object) References to matched non-local STV_DEFAULT symbols shouldn't be bound to definitions within the shared object. Implies
+Similar to
+.Cm --export-dynamic-symbol-list .
+When creating a shared object, implies
.Cm -Bsymbolic
but does not set DF_SYMBOLIC
.It Fl -EB
@@ -225,6 +224,12 @@ Put symbols in the dynamic symbol table.
.Cm -Bsymbolic-functions
or
.Cm --dynamic-list
+.It Fl -export-dynamic-symbol-list Ns = Ns Ar file
+Read a list of dynamic symbol patterns from
+.Ar file .
+Apply
+.Cm --export-dynamic-symbol
+on each pattern.
.It Fl -fatal-warnings
Treat warnings as errors.
.It Fl -filter Ns = Ns Ar value , Fl F Ar value
diff --git a/lld/test/ELF/export-dynamic-symbol.s b/lld/test/ELF/export-dynamic-symbol.s
index efd46112435e2..a6c292bfce287 100644
--- a/lld/test/ELF/export-dynamic-symbol.s
+++ b/lld/test/ELF/export-dynamic-symbol.s
@@ -3,7 +3,11 @@
# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
## For an executable, --export-dynamic-symbol exports a symbol if it is non-local and defined.
-# RUN: ld.lld -pie --export-dynamic-symbol foo %t.o -o %t
+# RUN: ld.lld -pie --export-dynamic-symbol foo --export-dynamic-symbol qux %t.o -o %t
+# RUN: llvm-nm -D -p %t | FileCheck %s
+# RUN: echo '{ foo; };' > %t1.list
+# RUN: echo '{ foo; qux; };' > %t2.list
+# RUN: ld.lld -pie --export-dynamic-symbol-list=%t2.list %t.o -o %t
# RUN: llvm-nm -D -p %t | FileCheck %s
## --export-dynamic exports all non-local defined symbols.
@@ -14,6 +18,7 @@
# CHECK-NOT: .
# START: T _start
# CHECK: T foo
+# CHECK: T qux
# CHECK-NOT: .
## --export-dynamic-symbol does not imply -u: %t1.a(%t1.o) is not fetched.
@@ -23,36 +28,53 @@
# RUN: ld.lld --export-dynamic-symbol bar %t1.a %t.o -o %t.nofetch
# RUN: llvm-nm %t.nofetch | FileCheck /dev/null --implicit-check-not=bar
+## For -shared, if no option expresses a symbolic intention, --export-dynamic-symbol is a no-op.
+# RUN: ld.lld -shared --export-dynamic-symbol foo %t.o -o %t.noop
+# RUN: llvm-objdump -d %t.noop | FileCheck --check-prefix=PLT2 %s
+# RUN: ld.lld -shared --export-dynamic-symbol-list %t2.list %t.o -o %t.noop
+# RUN: llvm-objdump -d %t.noop | FileCheck --check-prefix=PLT2 %s
+
## --export-dynamic-symbol can make a symbol preemptible even if it would be otherwise
## non-preemptible (due to -Bsymbolic, -Bsymbolic-functions or --dynamic-list).
# RUN: ld.lld -shared -Bsymbolic --export-dynamic-symbol nomatch %t.o -o %t.nopreempt
# RUN: llvm-objdump -d %t.nopreempt | FileCheck --check-prefix=NOPLT %s
# RUN: ld.lld -shared -Bsymbolic --export-dynamic-symbol foo %t.o -o %t.preempt
-# RUN: llvm-objdump -d %t.preempt | FileCheck --check-prefix=PLT %s
+# RUN: llvm-objdump -d %t.preempt | FileCheck --check-prefix=PLT1 %s
+# RUN: ld.lld -shared -Bsymbolic --export-dynamic-symbol-list %t1.list %t.o -o %t.preempt
+# RUN: llvm-objdump -d %t.preempt | FileCheck --check-prefix=PLT1 %s
## 'nomatch' does not match any symbol. Don't warn.
# RUN: ld.lld --fatal-warnings -shared -Bsymbolic-functions --export-dynamic-symbol nomatch %t.o -o %t.nopreempt2
# RUN: llvm-objdump -d %t.nopreempt2 | FileCheck --check-prefix=NOPLT %s
# RUN: ld.lld -shared -Bsymbolic-functions --export-dynamic-symbol foo %t.o -o %t.preempt2
-# RUN: llvm-objdump -d %t.preempt2 | FileCheck --check-prefix=PLT %s
+# RUN: llvm-objdump -d %t.preempt2 | FileCheck --check-prefix=PLT1 %s
# RUN: echo '{};' > %t.list
# RUN: ld.lld -shared --dynamic-list %t.list --export-dynamic-symbol foo %t.o -o %t.preempt3
-# RUN: llvm-objdump -d %t.preempt3 | FileCheck --check-prefix=PLT %s
+# RUN: llvm-objdump -d %t.preempt3 | FileCheck --check-prefix=PLT1 %s
## The option value is a glob.
# RUN: ld.lld -shared -Bsymbolic --export-dynamic-symbol 'f*' %t.o -o - | \
-# RUN: llvm-objdump -d - | FileCheck --check-prefix=PLT %s
+# RUN: llvm-objdump -d - | FileCheck --check-prefix=PLT1 %s
# RUN: ld.lld -shared -Bsymbolic --export-dynamic-symbol '[f]o[o]' %t.o -o - | \
-# RUN: llvm-objdump -d - | FileCheck --check-prefix=PLT %s
+# RUN: llvm-objdump -d - | FileCheck --check-prefix=PLT1 %s
# RUN: ld.lld -shared -Bsymbolic --export-dynamic-symbol 'f?o' %t.o -o - | \
-# RUN: llvm-objdump -d - | FileCheck --check-prefix=PLT %s
+# RUN: llvm-objdump -d - | FileCheck --check-prefix=PLT1 %s
+
+# PLT1: <foo at plt>
+# PLT1: <qux>
+
+# PLT2: <foo at plt>
+# PLT2: <qux at plt>
-# PLT: <foo at plt>
# NOPLT-NOT: <foo at plt>
+# NOPLT-NOT: <qux at plt>
-.global _start, foo
+.global _start, foo, qux
.type foo, @function
+.type qux, @function
_start:
call foo
+ call qux
foo:
+qux:
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