[lld] deaf121 - Warn when an output section name is longer than 8 characters
Reid Kleckner via llvm-commits
llvm-commits at lists.llvm.org
Fri Nov 1 13:01:14 PDT 2019
Author: Reid Kleckner
Date: 2019-11-01T12:59:13-07:00
New Revision: deaf121b657323fde17dd862a13b05e8b7ee6954
URL: https://github.com/llvm/llvm-project/commit/deaf121b657323fde17dd862a13b05e8b7ee6954
DIFF: https://github.com/llvm/llvm-project/commit/deaf121b657323fde17dd862a13b05e8b7ee6954.diff
LOG: Warn when an output section name is longer than 8 characters
Recent versions of Microsoft's dumpbin tool cannot handle such PE files.
LLVM tools and GNU tools can, and use this to encode long section names
like ".debug_info", which is commonly used for DWARF. Don't do this in
mingw mode or when -debug:dwarf is passed, since the user probably wants
long section names for DWARF sections.
PR43754
Reviewers: ruiu, mstorsjo
Differential Revision: https://reviews.llvm.org/D69594
Added:
Modified:
lld/COFF/Config.h
lld/COFF/Driver.cpp
lld/COFF/Writer.cpp
lld/test/COFF/long-section-name.test
Removed:
################################################################################
diff --git a/lld/COFF/Config.h b/lld/COFF/Config.h
index 309e1fbf99e3..07fa48b3ebc1 100644
--- a/lld/COFF/Config.h
+++ b/lld/COFF/Config.h
@@ -218,6 +218,7 @@ struct Configuration {
bool warnMissingOrderSymbol = true;
bool warnLocallyDefinedImported = true;
bool warnDebugInfoUnusable = true;
+ bool warnLongSectionNames = true;
bool incremental = true;
bool integrityCheck = false;
bool killAt = false;
diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index 9f43d8c36d3f..29c3fe7922fc 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -1188,6 +1188,8 @@ void LinkerDriver::link(ArrayRef<const char *> argsArr) {
config->warnDebugInfoUnusable = false;
else if (s == "4217")
config->warnLocallyDefinedImported = false;
+ else if (s == "longsections")
+ config->warnLongSectionNames = false;
// Other warning numbers are ignored.
}
}
@@ -1527,6 +1529,11 @@ void LinkerDriver::link(ArrayRef<const char *> argsArr) {
config->debugGHashes = debug == DebugKind::GHash;
config->debugSymtab = debug == DebugKind::Symtab;
+ // Don't warn about long section names, such as .debug_info, for mingw or when
+ // -debug:dwarf is requested.
+ if (config->mingw || config->debugDwarf)
+ config->warnLongSectionNames = false;
+
config->mapFile = getMapFile(args);
if (config->incremental && args.hasArg(OPT_profile)) {
diff --git a/lld/COFF/Writer.cpp b/lld/COFF/Writer.cpp
index 9729c6938ec8..9638f4202e06 100644
--- a/lld/COFF/Writer.cpp
+++ b/lld/COFF/Writer.cpp
@@ -1148,6 +1148,11 @@ void Writer::createSymbolAndStringTable() {
continue;
if ((sec->header.Characteristics & IMAGE_SCN_MEM_DISCARDABLE) == 0)
continue;
+ if (config->warnLongSectionNames) {
+ warn("section name " + sec->name +
+ " is longer than 8 characters and will use a non-standard string "
+ "table");
+ }
sec->setStringTableOff(addEntryToStringTable(sec->name));
}
diff --git a/lld/test/COFF/long-section-name.test b/lld/test/COFF/long-section-name.test
index 6cb88e17bfe5..458c44122ddb 100644
--- a/lld/test/COFF/long-section-name.test
+++ b/lld/test/COFF/long-section-name.test
@@ -1,8 +1,18 @@
# RUN: yaml2obj < %s > %t.obj
-# RUN: lld-link /out:%t.exe /entry:main %t.obj
+# RUN: lld-link /out:%t.exe /entry:main %t.obj 2>&1 | FileCheck %s --check-prefix=WARN
# RUN: llvm-readobj --sections %t.exe | FileCheck %s
-# RUN: lld-link /debug /out:%t2.exe /entry:main %t.obj
+# RUN: lld-link /debug /out:%t2.exe /entry:main %t.obj 2>&1 | FileCheck %s --check-prefix=WARN
# RUN: llvm-readobj --sections %t2.exe | FileCheck %s
+#
+# No warnings in mingw mode or with ignore flag.
+# RUN: lld-link /out:%t.exe /entry:main %t.obj /ignore:longsections 2>&1 | FileCheck %s --check-prefix=IGNORE --allow-empty
+# RUN: lld-link /out:%t.exe /entry:main %t.obj -lldmingw 2>&1 | FileCheck %s --check-prefix=IGNORE --allow-empty
+# RUN: lld-link /out:%t.exe /entry:main %t.obj -debug:dwarf 2>&1 | FileCheck %s --check-prefix=IGNORE --allow-empty
+
+# WARN: warning: section name .data_long_section_name is longer than 8 characters and will use a non-standard string table
+# WARN: warning: section name .text_long_section_name is longer than 8 characters and will use a non-standard string table
+
+# IGNORE-NOT: warning:
# CHECK: Name: .eh_fram (
# CHECK: Name: .data_long_section_name
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