[ELF] --wrap: don't clear sym->isUsedInRegularObj if real->isUsedInRegularObj; set wrap's initial binding to sym's
Fix PR49897: if `__real_foo` has the isUsedInRegularObj bit set, we need to
retain `foo` in .symtab, even if `foo` is undefined. The new behavior will match
GNU ld.
Before the patch, we produced an R_X86_64_JUMP_SLOT relocation referencing the
index 0 undefined symbol, which would be erroed by glibc
(see f96ff3c0f8ebd941b3f6b345164c3d858b781484).
While here, fix another bug: if `__wrap_foo` does not exist, its initial binding
should be `foo`'s.
GitOrigin-RevId: 7c74ce3c686938e95a08a05ea1e2a714eac43167
diff --git a/ELF/Driver.cpp b/ELF/Driver.cpp
index 2daee21..1b840c1 100644
--- a/ELF/Driver.cpp
+++ b/ELF/Driver.cpp
@@ -1888,8 +1888,9 @@
Undefined{nullptr, name, STB_GLOBAL, STV_DEFAULT, 0});
}
-static Symbol *addUnusedUndefined(StringRef name) {
- Undefined sym{nullptr, name, STB_GLOBAL, STV_DEFAULT, 0};
+static Symbol *addUnusedUndefined(StringRef name,
+ uint8_t binding = STB_GLOBAL) {
+ Undefined sym{nullptr, name, binding, STV_DEFAULT, 0};
sym.isUsedInRegularObj = false;
return symtab->addSymbol(sym);
}
@@ -1953,7 +1954,8 @@
continue;
Symbol *real = addUnusedUndefined(saver.save("__real_" + name));
- Symbol *wrap = addUnusedUndefined(saver.save("__wrap_" + name));
+ Symbol *wrap =
+ addUnusedUndefined(saver.save("__wrap_" + name), sym->binding);
v.push_back({sym, real, wrap});
// We want to tell LTO not to inline symbols to be overwritten
diff --git a/ELF/SymbolTable.cpp b/ELF/SymbolTable.cpp
index 6283d94..70aea28 100644
--- a/ELF/SymbolTable.cpp
+++ b/ELF/SymbolTable.cpp
@@ -42,7 +42,7 @@
if (real->exportDynamic)
sym->exportDynamic = true;
- if (sym->isUndefined())
+ if (!real->isUsedInRegularObj && sym->isUndefined())
sym->isUsedInRegularObj = false;
// Now renaming is complete, and no one refers to real. We drop real from
diff --git a/test/ELF/Inputs/wrap-dynamic-undef.s b/test/ELF/Inputs/wrap-dynamic-undef.s
deleted file mode 100644
index ade7955..0000000
--- a/test/ELF/Inputs/wrap-dynamic-undef.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.global foo
-foo:
diff --git a/test/ELF/wrap-dynamic-undef.s b/test/ELF/wrap-dynamic-undef.s
index af2871c..ca16981 100644
--- a/test/ELF/wrap-dynamic-undef.s
+++ b/test/ELF/wrap-dynamic-undef.s
@@ -1,9 +1,10 @@
# REQUIRES: x86
-# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t1.o
-# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/wrap-dynamic-undef.s -o %t2.o
-# RUN: ld.lld %t2.o -o %t2.so -shared
-# RUN: ld.lld %t1.o %t2.so -o %t --wrap foo
-# RUN: llvm-readelf --dyn-syms %t | FileCheck %s
+# RUN: split-file %s %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/a.s -o %t/a.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/def.s -o %t/def.o
+# RUN: ld.lld %t/def.o -o %t/def.so -shared --soname=def
+# RUN: ld.lld %t/a.o %t/def.so -o %t1 --wrap foo
+# RUN: llvm-readelf --dyn-syms %t1 | FileCheck %s
# Test that the dynamic relocation uses foo. We used to produce a
# relocation with __real_foo.
@@ -12,6 +13,29 @@
# CHECK: NOTYPE LOCAL DEFAULT UND
# CHECK-NEXT: NOTYPE GLOBAL DEFAULT UND foo
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/b.s -o %t/b.o
+# RUN: ld.lld -shared --wrap foo %t/b.o -o %t2.so
+# RUN: llvm-readelf --dyn-syms %t2.so | FileCheck %s --check-prefix=SYM2
+
+# SYM2: Symbol table '.dynsym' contains 4 entries:
+# SYM2: NOTYPE LOCAL DEFAULT UND
+# SYM2-NEXT: NOTYPE WEAK DEFAULT UND foo
+# SYM2-NEXT: NOTYPE WEAK DEFAULT UND __wrap_foo
+# SYM2-NEXT: NOTYPE GLOBAL DEFAULT [[#]] _start
+
+#--- a.s
.global _start
_start:
callq __real_foo@plt
+
+#--- def.s
+.globl foo
+foo:
+
+#--- b.s
+.weak foo
+.weak __real_foo
+.global _start
+_start:
+ call __real_foo@plt
+ call foo@plt
