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Add support for export_dynamic cmdline option and behaviour.

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This option matches the behaviour of ld64, that is it prevents globals
from being dead stripped in executables and dylibs.

Reviewed by Lang Hames

Differential Revision: http://reviews.llvm.org/D16026

llvm-svn: 258554
This commit is contained in:
Pete Cooper
2016-01-22 21:13:24 +00:00
parent 7849ad0f72
commit 351164504a
6 changed files with 69 additions and 4 deletions
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3
lld/include/lld/ReaderWriter/MachOLinkingContext.h
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@@ -84,7 +84,8 @@ public:
/// Initializes the context to sane default values given the specified output
/// file type, arch, os, and minimum os version. This should be called before
/// other setXXX() methods.
void configure(HeaderFileType type, Arch arch, OS os, uint32_t minOSVersion);
void configure(HeaderFileType type, Arch arch, OS os, uint32_t minOSVersion,
bool exportDynamicSymbols);
void addPasses(PassManager &pm) override;
bool validateImpl(raw_ostream &diagnostics) override;

9
lld/lib/Driver/DarwinLdDriver.cpp
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@@ -385,9 +385,16 @@ bool DarwinLdDriver::parse(llvm::ArrayRef<const char *> args,
// No min-os version on command line, check environment variables
}
// Handle export_dynamic
// FIXME: Should we warn when this applies to something other than a static
// executable or dylib? Those are the only cases where this has an effect.
// Note, this has to come before ctx.configure() so that we get the correct
// value for _globalsAreDeadStripRoots.
bool exportDynamicSymbols = parsedArgs.hasArg(OPT_export_dynamic);
// Now that there's enough information parsed in, let the linking context
// set up default values.
ctx.configure(fileType, arch, os, minOSVersion);
ctx.configure(fileType, arch, os, minOSVersion, exportDynamicSymbols);
// Handle -e xxx
if (llvm::opt::Arg *entry = parsedArgs.getLastArg(OPT_entry))

3
lld/lib/Driver/DarwinLdOptions.td
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@@ -84,6 +84,9 @@ def stack_size : Separate<["-"], "stack_size">,
HelpText<"Specifies the maximum stack size for the main thread in a program. "
"Must be a page-size multiple. (default=8Mb)">,
Group<grp_main>;
def export_dynamic : Flag<["-"], "export_dynamic">,
HelpText<"Preserves all global symbols in main executables during LTO">,
Group<grp_main>;
// dylib executable options
def grp_dylib : OptionGroup<"opts">, HelpText<"DYLIB EXECUTABLE OPTIONS">;

6
lld/lib/ReaderWriter/MachO/MachOLinkingContext.cpp
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@@ -155,7 +155,8 @@ MachOLinkingContext::MachOLinkingContext()
MachOLinkingContext::~MachOLinkingContext() {}
void MachOLinkingContext::configure(HeaderFileType type, Arch arch, OS os,
uint32_t minOSVersion) {
uint32_t minOSVersion,
bool exportDynamicSymbols) {
_outputMachOType = type;
_arch = arch;
_os = os;
@@ -218,9 +219,10 @@ void MachOLinkingContext::configure(HeaderFileType type, Arch arch, OS os,
case OS::unknown:
break;
}
setGlobalsAreDeadStripRoots(exportDynamicSymbols);
break;
case llvm::MachO::MH_DYLIB:
setGlobalsAreDeadStripRoots(true);
setGlobalsAreDeadStripRoots(exportDynamicSymbols);
break;
case llvm::MachO::MH_BUNDLE:
break;

27
lld/test/mach-o/dead-strip-globals.yaml Normal file
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@@ -0,0 +1,27 @@
# RUN: lld -flavor darwin -arch x86_64 -dead_strip -export_dynamic %s -dylib %p/Inputs/libSystem.yaml -o %t.dylib -print_atoms | FileCheck -check-prefix=CHECK1 %s
# RUN: lld -flavor darwin -arch x86_64 -export_dynamic -dead_strip %s -dylib %p/Inputs/libSystem.yaml -o %t.dylib -print_atoms | FileCheck -check-prefix=CHECK1 %s
# RUN: lld -flavor darwin -arch x86_64 -dead_strip %s -dylib %p/Inputs/libSystem.yaml -o %t2.dylib -print_atoms | FileCheck -check-prefix=CHECK2 %s
#
# Test that -export_dynamic -dead-strip from removing globals.
#
---
defined-atoms:
- name: def
scope: global
dead-strip: never
- name: dead
scope: global
shared-library-atoms:
- name: dyld_stub_binder
load-name: /usr/lib/libSystem.B.dylib
type: unknown
...
# CHECK1: name: def
# CHECK1: name: dead
# CHECK2: name: def
# CHECK2-NOT: name: dead

25
lld/unittests/DriverTests/DarwinLdDriverTest.cpp
View File

@@ -84,9 +84,34 @@ TEST_F(DarwinLdParserTest, DeadStripRootsExe) {
TEST_F(DarwinLdParserTest, DeadStripRootsDylib) {
EXPECT_TRUE(parse("ld", "-arch", "x86_64", "-dylib", "-dead_strip", "foo.o",
nullptr));
EXPECT_FALSE(_ctx.globalsAreDeadStripRoots());
}
TEST_F(DarwinLdParserTest, DeadStripRootsRelocatable) {
EXPECT_TRUE(parse("ld", "-arch", "x86_64", "-r", "-dead_strip", "foo.o",
nullptr));
EXPECT_FALSE(_ctx.globalsAreDeadStripRoots());
}
TEST_F(DarwinLdParserTest, DeadStripRootsExportDynamicExe) {
EXPECT_TRUE(parse("ld", "-arch", "x86_64", "-dead_strip",
"-export_dynamic", "foo.o", nullptr));
EXPECT_TRUE(_ctx.globalsAreDeadStripRoots());
}
TEST_F(DarwinLdParserTest, DeadStripRootsExportDynamicDylib) {
EXPECT_TRUE(parse("ld", "-arch", "x86_64", "-dylib", "-dead_strip",
"-export_dynamic", "foo.o",
nullptr));
EXPECT_TRUE(_ctx.globalsAreDeadStripRoots());
}
TEST_F(DarwinLdParserTest, DeadStripRootsExportDynamicRelocatable) {
EXPECT_TRUE(parse("ld", "-arch", "x86_64", "-r", "-dead_strip",
"-export_dynamic", "foo.o", nullptr));
EXPECT_FALSE(_ctx.globalsAreDeadStripRoots());
}
TEST_F(DarwinLdParserTest, Arch) {
EXPECT_TRUE(parse("ld", "-arch", "x86_64", "foo.o", nullptr));
EXPECT_EQ(MachOLinkingContext::arch_x86_64, _ctx.arch());