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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
This commit is contained in:
Reid Kleckner 2019-10-29 15:57:40 -07:00
parent a264e85dd9
commit deaf121b65
4 changed files with 25 additions and 2 deletions
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1
lld/COFF/Config.h
View File

@ -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;

7
lld/COFF/Driver.cpp
View File

@ -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)) {

5
lld/COFF/Writer.cpp
View File

@ -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));
}

14
lld/test/COFF/long-section-name.test
View File

@ -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