[ELF] Don't warn on undefined symbols if UnresolvedPolicy::Ignore is used
Summary:
Add a condition UnresolvedPolicy::Ignore to elf::warnUnorderedSymbol to suppress Sym->isUndefined() warnings from both
1) --symbol-ordering-file=
2) .llvm.call-graph-profile
If --unresolved-symbols=ignore-all is used,
no "undefined symbol" error/warning is emitted. It makes sense to not warn unorderable symbols.
Otherwise,
If an executable is linked, the default policy UnresolvedPolicy::ErrorOrWarn will issue a "undefined symbol" error. The unorderable symbol warning is redundant.
If a shared object is linked, it is possible that only part of object files are used and some symbols are left undefined. The warning is not very necessary.
In particular for .llvm.call-graph-profile, when linking a shared object, a call graph profile may contain undefined symbols. This case generated a warning before but it will be suppressed by this patch.
Reviewers: ruiu, davidxl, espindola
Reviewed By: ruiu
Subscribers: grimar, emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D53044
git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@344195 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/ELF/Symbols.cpp b/ELF/Symbols.cpp
index 94706a9..7a35377 100644
--- a/ELF/Symbols.cpp
+++ b/ELF/Symbols.cpp
@@ -263,6 +263,15 @@
if (!Config->WarnSymbolOrdering)
return;
+ // If UnresolvedPolicy::Ignore is used, no "undefined symbol" error/warning
+ // is emitted. It makes sense to not warn on undefined symbols.
+ //
+ // Note, ld.bfd --symbol-ordering-file= does not warn on undefined symbols,
+ // but we don't have to be compatible here.
+ if (Sym->isUndefined() &&
+ Config->UnresolvedSymbols == UnresolvedPolicy::Ignore)
+ return;
+
const InputFile *File = Sym->File;
auto *D = dyn_cast<Defined>(Sym);
diff --git a/test/ELF/cgprofile-shared-warn.s b/test/ELF/cgprofile-shared-warn.s
new file mode 100644
index 0000000..74cfb03
--- /dev/null
+++ b/test/ELF/cgprofile-shared-warn.s
@@ -0,0 +1,11 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
+# RUN: ld.lld --shared %t.o -o /dev/null 2>&1 | count 0
+# RUN: ld.lld -e A --unresolved-symbols=ignore-all %t.o -o /dev/null 2>&1 | count 0
+ .section .text.A,"ax",@progbits
+ .globl A
+A:
+ callq B
+
+ .cg_profile A, B, 10
diff --git a/test/ELF/symbol-ordering-file-warnings.s b/test/ELF/symbol-ordering-file-warnings.s
index 71414bf..abbafc4 100644
--- a/test/ELF/symbol-ordering-file-warnings.s
+++ b/test/ELF/symbol-ordering-file-warnings.s
@@ -19,11 +19,6 @@
# RUN: --unresolved-symbols=ignore-all --no-warn-symbol-ordering --warn-symbol-ordering 2>&1 | \
# RUN: FileCheck %s --check-prefixes=WARN,MISSING
-# Check that a warning is emitted for undefined symbols.
-# RUN: echo "undefined" > %t-order-undef.txt
-# RUN: ld.lld %t1.o %t3.o -o %t --symbol-ordering-file %t-order-undef.txt \
-# RUN: --unresolved-symbols=ignore-all 2>&1 | FileCheck %s --check-prefixes=WARN,UNDEFINED
-
# Check that a warning is emitted for imported shared symbols.
# RUN: echo "shared" > %t-order-shared.txt
# RUN: ld.lld %t1.o %t.so -o %t --symbol-ordering-file %t-order-shared.txt \
@@ -97,7 +92,7 @@
# RUN: echo "_GLOBAL_OFFSET_TABLE_" >> %t-order-multi.txt
# RUN: echo "_start" >> %t-order-multi.txt
# RUN: ld.lld %t1.o %t3.o %t.so -o %t --symbol-ordering-file %t-order-multi.txt --gc-sections -T %t.script \
-# RUN: --unresolved-symbols=ignore-all 2>&1 | FileCheck %s --check-prefixes=WARN,SAMESYM,ABSOLUTE,SHARED,UNDEFINED,GC,DISCARD,MISSING2,SYNTHETIC
+# RUN: 2>&1 | FileCheck %s --check-prefixes=WARN,SAMESYM,ABSOLUTE,SHARED,UNDEFINED,GC,DISCARD,MISSING2,SYNTHETIC
# WARN-NOT: warning:
# SAMESYM: warning: {{.*}}.txt: duplicate ordered symbol: _start
@@ -115,10 +110,12 @@
# ABSOLUTE: warning: {{.*}}1.o: unable to order absolute symbol: absolute
# WARN-NOT: warning:
# MISSING: warning: symbol ordering file: no such symbol: missing
+# WARN-NOT: warning:
# MISSING2: warning: symbol ordering file: no such symbol: missing_sym
+# WARN-NOT: warning:
# COMDAT: warning: {{.*}}1.o: unable to order discarded symbol: comdat
-# MULTI: warning: {{.*}}3.o: unable to order undefined symbol: multi
-# MULTI-NEXT: warning: {{.*}}2.o: unable to order absolute symbol: multi
+# WARN-NOT: warning:
+# MULTI: warning: {{.*}}2.o: unable to order absolute symbol: multi
# WARN-NOT: warning:
absolute = 0x1234
