[lld] 13816e0 - [LLD][ELF] --wrap: __real_foo references should trigger archive extraction for foo
Ben Dunbobbin via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 18 04:53:58 PDT 2022
Author: Ben Dunbobbin
Date: 2022-10-18T12:53:06+01:00
New Revision: 13816e0358123baa411419048a9ce5c432ddab55
URL: https://github.com/llvm/llvm-project/commit/13816e0358123baa411419048a9ce5c432ddab55
DIFF: https://github.com/llvm/llvm-project/commit/13816e0358123baa411419048a9ce5c432ddab55.diff
LOG: [LLD][ELF] --wrap: __real_foo references should trigger archive extraction for foo
A reference to __real_foo should trigger archive extraction of the input file that defines foo, otherwise a link using --wrap=foo might fail to link with an undefined reference to foo.
This matches bfd linker behaviour.
Differential Revision: https://reviews.llvm.org/D135897
Added:
lld/test/ELF/wrap-extract-real.ll
lld/test/ELF/wrap-extract-real.s
Modified:
lld/ELF/Driver.cpp
Removed:
################################################################################
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index dd6a77a6da337..48990d00f44b8 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -2243,9 +2243,16 @@ static std::vector<WrappedSymbol> addWrappedSymbols(opt::InputArgList &args) {
if (!sym)
continue;
- Symbol *real = addUnusedUndefined(saver().save("__real_" + name));
Symbol *wrap =
addUnusedUndefined(saver().save("__wrap_" + name), sym->binding);
+
+ // If __real_ is referenced, pull in the symbol if it is lazy. Do this after
+ // processing __wrap_ as that may have referenced __real_.
+ StringRef realName = saver().save("__real_" + name);
+ if (symtab.find(realName))
+ addUnusedUndefined(name, sym->binding);
+
+ Symbol *real = addUnusedUndefined(realName);
v.push_back({sym, real, wrap});
// We want to tell LTO not to inline symbols to be overwritten
diff --git a/lld/test/ELF/wrap-extract-real.ll b/lld/test/ELF/wrap-extract-real.ll
new file mode 100644
index 0000000000000..2ab6b3187ae39
--- /dev/null
+++ b/lld/test/ELF/wrap-extract-real.ll
@@ -0,0 +1,66 @@
+# REQUIRES: x86
+## --wrap=xxx should trigger archive extraction for symbol xxx for references to __real_xxx.
+
+# RUN: rm -rf %t && split-file %s %t && cd %t
+# RUN: llvm-as _start.ll -o _start.o
+# RUN: llvm-as _start_ref__real_foo.ll -o _start_ref__real_foo.o
+# RUN: llvm-as wrap.ll -o wrap.o
+# RUN: llvm-as foo.ll -o foo.o
+
+## Test when the reference to __real_foo is not in __wrap_foo.
+# RUN: ld.lld _start_ref__real_foo.o --start-lib foo.o --end-lib --wrap foo -o %t_real.elf
+# RUN: llvm-readelf --symbols %t_real.elf | FileCheck %s --check-prefix=REAL
+
+# REAL: Symbol table '.symtab' contains 5 entries:
+# REAL-NEXT: Value Size Type Bind Vis Ndx Name
+# REAL-NEXT: {{.*}} {{.*}} NOTYPE LOCAL DEFAULT UND
+# REAL-NEXT: {{.*}} {{.*}} FILE LOCAL DEFAULT ABS ld-temp.o
+# REAL-NEXT: {{.*}} {{.*}} FUNC GLOBAL DEFAULT [[#]] _start
+# REAL-NEXT: {{.*}} {{.*}} FUNC WEAK DEFAULT [[#]] foo
+# REAL-NEXT: {{.*}} {{.*}} NOTYPE GLOBAL DEFAULT UND __wrap_foo
+
+## Test when the reference to __real_foo is in __wrap_foo.
+# RUN: ld.lld _start.o --start-lib wrap.o --end-lib --start-lib foo.o --end-lib --wrap foo -o %t_wrap_real.elf
+# RUN: llvm-readelf --symbols %t_wrap_real.elf | FileCheck %s --check-prefix=WRAP_REAL
+
+# WRAP_REAL: Symbol table '.symtab' contains 5 entries:
+# WRAP_REAL-NEXT: Value Size Type Bind Vis Ndx Name
+# WRAP_REAL-NEXT: {{.*}} {{.*}} NOTYPE LOCAL DEFAULT UND
+# WRAP_REAL-NEXT: {{.*}} {{.*}} FILE LOCAL DEFAULT ABS ld-temp.o
+# WRAP_REAL-NEXT: {{.*}} {{.*}} FUNC GLOBAL DEFAULT [[#]] _start
+# WRAP_REAL-NEXT: {{.*}} {{.*}} FUNC GLOBAL DEFAULT [[#]] __wrap_foo
+# WRAP_REAL-NEXT: {{.*}} {{.*}} FUNC WEAK DEFAULT [[#]] foo
+
+#--- _start.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-elf"
+define void @_start() {
+ ret void
+}
+
+#--- _start_ref__real_foo.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-elf"
+define void @_start() {
+ call void @__real_foo()
+ ret void
+}
+
+declare void @__real_foo()
+
+#--- wrap.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-elf"
+define void @__wrap_foo() {
+ call void @__real_foo()
+ ret void
+}
+
+declare void @__real_foo()
+
+#--- foo.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-elf"
+define void @foo() {
+ ret void
+}
diff --git a/lld/test/ELF/wrap-extract-real.s b/lld/test/ELF/wrap-extract-real.s
new file mode 100644
index 0000000000000..52f98e5a82fcf
--- /dev/null
+++ b/lld/test/ELF/wrap-extract-real.s
@@ -0,0 +1,42 @@
+# REQUIRES: x86
+## --wrap=xxx should trigger archive extraction for symbol xxx for references to __real_xxx.
+
+# RUN: rm -rf %t && split-file %s %t && cd %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64 _start.s -o _start.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64 ref__real_foo.s -o ref__real_foo.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64 wrap.s -o wrap.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64 foo.s -o foo.o
+
+## Test when the reference to __real_foo is not in __wrap_foo.
+# RUN: ld.lld _start.o ref__real_foo.o --start-lib foo.o --end-lib --wrap foo -o %t_real.elf
+# RUN: llvm-readelf --symbols %t_real.elf | FileCheck %s --check-prefix=REAL
+
+# REAL: Symbol table '.symtab' contains 4 entries:
+# REAL-NEXT: Value Size Type Bind Vis Ndx Name
+# REAL-NEXT: {{.*}} 0 NOTYPE LOCAL DEFAULT UND
+# REAL-NEXT: {{.*}} 0 NOTYPE GLOBAL DEFAULT [[#]] _start
+# REAL-NEXT: {{.*}} 0 NOTYPE GLOBAL DEFAULT [[#]] foo
+# REAL-NEXT: {{.*}} 0 NOTYPE GLOBAL DEFAULT UND __wrap_foo
+
+## Test when the reference to __real_foo is in __wrap_foo.
+# RUN: ld.lld _start.o --start-lib wrap.o --end-lib --start-lib foo.o --end-lib --wrap foo -o %t_wrap_real.elf
+# RUN: llvm-readelf --symbols %t_wrap_real.elf | FileCheck %s --check-prefix=WRAP_REAL
+
+# WRAP_REAL: Symbol table '.symtab' contains 4 entries:
+# WRAP_REAL-NEXT: Value Size Type Bind Vis Ndx Name
+# WRAP_REAL-NEXT: {{.*}} 0 NOTYPE LOCAL DEFAULT UND
+# WRAP_REAL-NEXT: {{.*}} 0 NOTYPE GLOBAL DEFAULT [[#]] _start
+# WRAP_REAL-NEXT: {{.*}} 0 NOTYPE GLOBAL DEFAULT [[#]] __wrap_foo
+# WRAP_REAL-NEXT: {{.*}} 0 NOTYPE GLOBAL DEFAULT [[#]] foo
+
+#--- _start.s
+.global _start; _start:; ret
+
+#--- ref__real_foo.s
+call __real_foo
+
+#--- wrap.s
+.global __wrap_foo; __wrap_foo:; call __real_foo
+
+#--- foo.s
+.global foo; foo:; ret
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