lld: add -z interpose support
-z interpose sets the DF_1_INTERPOSE flag, marking the object as an
interposer.
Via FreeBSD PR 230604, linking Valgrind with lld failed.
Differential Revision: https://reviews.llvm.org/D52094
llvm-svn: 342239
diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
index acaf3b3..8dadfaa 100644
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -184,6 +184,7 @@
bool ZGlobal;
bool ZHazardplt;
bool ZInitfirst;
+ bool ZInterpose;
bool ZKeepTextSectionPrefix;
bool ZNodelete;
bool ZNodlopen;
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 49ad1b3..f7abcfe 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -341,9 +341,10 @@
static bool isKnown(StringRef S) {
return S == "combreloc" || S == "copyreloc" || S == "defs" ||
S == "execstack" || S == "global" || S == "hazardplt" ||
- S == "initfirst" || S == "keep-text-section-prefix" || S == "lazy" ||
- S == "muldefs" || S == "nocombreloc" || S == "nocopyreloc" ||
- S == "nodelete" || S == "nodlopen" || S == "noexecstack" ||
+ S == "initfirst" || S == "interpose" ||
+ S == "keep-text-section-prefix" || S == "lazy" || S == "muldefs" ||
+ S == "nocombreloc" || S == "nocopyreloc" || S == "nodelete" ||
+ S == "nodlopen" || S == "noexecstack" ||
S == "nokeep-text-section-prefix" || S == "norelro" || S == "notext" ||
S == "now" || S == "origin" || S == "relro" || S == "retpolineplt" ||
S == "rodynamic" || S == "text" || S == "wxneeded" ||
@@ -836,6 +837,7 @@
Config->ZGlobal = hasZOption(Args, "global");
Config->ZHazardplt = hasZOption(Args, "hazardplt");
Config->ZInitfirst = hasZOption(Args, "initfirst");
+ Config->ZInterpose = hasZOption(Args, "interpose");
Config->ZKeepTextSectionPrefix = getZFlag(
Args, "keep-text-section-prefix", "nokeep-text-section-prefix", false);
Config->ZNodelete = hasZOption(Args, "nodelete");
diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
index 3f1a15b..b547956 100644
--- a/lld/ELF/SyntheticSections.cpp
+++ b/lld/ELF/SyntheticSections.cpp
@@ -1268,6 +1268,8 @@
DtFlags1 |= DF_1_GLOBAL;
if (Config->ZInitfirst)
DtFlags1 |= DF_1_INITFIRST;
+ if (Config->ZInterpose)
+ DtFlags1 |= DF_1_INTERPOSE;
if (Config->ZNodelete)
DtFlags1 |= DF_1_NODELETE;
if (Config->ZNodlopen)
diff --git a/lld/docs/ld.lld.1 b/lld/docs/ld.lld.1
index 8f71468..34fb1ec 100644
--- a/lld/docs/ld.lld.1
+++ b/lld/docs/ld.lld.1
@@ -3,7 +3,7 @@
.\"
.\" This man page documents only lld's ELF linking support, obtained originally
.\" from FreeBSD.
-.Dd July 30, 2018
+.Dd September 14, 2018
.Dt LD.LLD 1
.Os
.Sh NAME
@@ -446,6 +446,12 @@
Sets the
.Dv DF_1_INITFIRST
flag to indicate the module should be initialized first.
+.It Cm interpose
+Set the
+.Dv DF_1_INTERPOSE
+flag to indicate to the runtime linker that the object is an interposer.
+During symbol resolution interposers are searched after the application
+but before other dependencies.
.It Cm muldefs
Do not error if a symbol is defined multiple times.
The first definition will be used.
diff --git a/lld/test/ELF/dt_flags.s b/lld/test/ELF/dt_flags.s
index 310a1db..8f84dfc 100644
--- a/lld/test/ELF/dt_flags.s
+++ b/lld/test/ELF/dt_flags.s
@@ -3,8 +3,8 @@
# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
# RUN: ld.lld -shared %t -o %t.so
-# RUN: ld.lld -z global -z initfirst -z now -z nodelete -z nodlopen -z origin \
-# RUN: -Bsymbolic %t %t.so -o %t1
+# RUN: ld.lld -z global -z initfirst -z interpose -z now -z nodelete \
+# RUN: -z nodlopen -z origin -Bsymbolic %t %t.so -o %t1
# RUN: llvm-readobj -dynamic-table %t1 | FileCheck -check-prefix=FLAGS %s
# RUN: ld.lld %t %t.so -o %t2
@@ -15,7 +15,7 @@
# FLAGS: DynamicSection [
# FLAGS: 0x000000000000001E FLAGS ORIGIN SYMBOLIC BIND_NOW
-# FLAGS: 0x000000006FFFFFFB FLAGS_1 NOW GLOBAL NODELETE INITFIRST NOOPEN ORIGIN
+# FLAGS: 0x000000006FFFFFFB FLAGS_1 NOW GLOBAL NODELETE INITFIRST NOOPEN ORIGIN INTERPOSE
# FLAGS: ]
# CHECK: DynamicSection [