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Limit dyld image suffixes guessed by guessLibraryShortName() 

Summary:
guessLibraryShortName() separates a full Mach-O dylib install name path
into a short name and a dyld image suffix. The short name is the name
of the dylib without its path or extension. The dyld image suffix is a
string used by dyld to load variants of dylibs if available at runtime;
for example, "when binding this process, load 'debug' variants of all
required dylibs." dyld knows exactly what the image suffix is, but
by convention diagnostic tools such as llvm-nm attempt to guess suffix
names by looking at the install name path. 

These dyld image suffixes are separated from the short name by a '_'
character. Because the '_' character is commonly used to separate words
in filenames guessLibraryShortName() cannot reliably separate a dylib's
short name from an arbitrary image suffix; imagine if both the short
name and the suffix contains an '_' character! To better deal with this
ambiguity, guessLibraryShortName() will recognize only "_debug" and
"_profile" as valid Suffix values. Calling code needs to be tolerant of
guessLibraryShortName() guessing incorrectly.

The previous implementation of guessLibraryShortName() did not allow
'_' characters to appear in short names. When present, the short name
would be  truncated, e.g., "libcompiler_rt" => "libcompiler". This
change allows "libcompiler_rt" and "libcompiler_rt_debug" to both be
recognized as "libcompiler_rt".

rdar://47412244

Reviewers: kledzik, lhames, pete

Reviewed By: pete

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D56978

llvm-svn: 352104
This commit is contained in:
Michael Trent 2019-01-24 20:59:44 +00:00
parent 7fca260dc8
commit f4c902bd77
3 changed files with 26 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
llvm/lib/Object/MachOObjectFile.cpp
View File

@ -2241,9 +2241,18 @@ uint8_t MachOObjectFile::getRelocationLength(DataRefImpl Rel) const {
// one of the two following forms:
// libFoo.A.dylib
// libFoo.dylib
//
// The library may have a suffix trailing the name Foo of the form:
// libFoo_profile.A.dylib
// libFoo_profile.dylib
// These dyld image suffixes are separated from the short name by a '_'
// character. Because the '_' character is commonly used to separate words in
// filenames guessLibraryShortName() cannot reliably separate a dylib's short
// name from an arbitrary image suffix; imagine if both the short name and the
// suffix contains an '_' character! To better deal with this ambiguity,
// guessLibraryShortName() will recognize only "_debug" and "_profile" as valid
// Suffix values. Calling code needs to be tolerant of guessLibraryShortName()
// guessing incorrectly.
//
// The Name of the dynamic library is also recognized as a library name if it
// has the following form:
@ -2251,7 +2260,6 @@ uint8_t MachOObjectFile::getRelocationLength(DataRefImpl Rel) const {
//
// If the Name of the dynamic library is none of the forms above then a NULL
// StringRef is returned.
//
StringRef MachOObjectFile::guessLibraryShortName(StringRef Name,
bool &isFramework,
StringRef &Suffix) {
@ -2271,7 +2279,10 @@ StringRef MachOObjectFile::guessLibraryShortName(StringRef Name,
Idx = Foo.rfind('_');
if (Idx != Foo.npos && Foo.size() >= 2) {
Suffix = Foo.slice(Idx, Foo.npos);
Foo = Foo.slice(0, Idx);
if (Suffix != "_debug" && Suffix != "_profile")
Suffix = StringRef();
else
Foo = Foo.slice(0, Idx);
}
// First look for the form Foo.framework/Foo
@ -2332,10 +2343,14 @@ guess_library:
else
b = b+1;
// ignore any suffix after an underbar like Foo_profile.A.dylib
Idx = Name.find('_', b);
Idx = Name.rfind('_');
if (Idx != Name.npos && Idx != b) {
Lib = Name.slice(b, Idx);
Suffix = Name.slice(Idx, a);
if (Suffix != "_debug" && Suffix != "_profile") {
Suffix = StringRef();
Lib = Name.slice(b, a);
}
}
else
Lib = Name.slice(b, a);

BIN
llvm/test/Object/Inputs/darwin-m-test3.macho-x86-64
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12
llvm/test/Object/nm-darwin-m.test
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@ -19,8 +19,8 @@ test2: (indirect) external _i (for __i)
# This is testing is using darwin-m-test3.macho-x86-64 that is linked with
# dylibs that have the follow set of -install_names:
# Foo.framework/Foo
# /System/Library/Frameworks/FooPath.framework/FooPath
# Foo.framework/Foo
# /System/Library/Frameworks/FooPath.framework/FooPath
# FooSuffix.framework/FooSuffix_debug
# /System/Library/Frameworks/FooPathSuffix.framework/FooPathSuffix_profile
# FooVers.framework/Versions/A/FooVers
@ -32,8 +32,10 @@ test2: (indirect) external _i (for __i)
# /usr/lib/libPathATS.A_profile.dylib
# QT.A.qtx
# /lib/QTPath.qtx
# /usr/lib/libfoo_bar.dylib
# /usr/lib/libfoo_bar_profile.dylib
# /usr/lib/libSystem.B.dylib
# to test that MachOObjectFile::guessLibraryShortName() is correctly parsing
# to test that MachOObjectFile::guessLibraryShortName() is correctly parsing
# them into their short names.
test3: 0000000100000000 (__TEXT,__text) [referenced dynamically] external __mh_execute_header
test3: (undefined) external _atsPathVersSuffix (from libPathATS)
@ -44,7 +46,9 @@ test3: (undefined) external _fooPathSuffix (from FooPathSuffix)
test3: (undefined) external _fooPathVers (from FooPathVers)
test3: (undefined) external _fooSuffix (from FooSuffix)
test3: (undefined) external _fooVers (from FooVers)
test3: 0000000100000e60 (__TEXT,__text) external _main
test3: (undefined) external _foo_bar (from libfoo_bar)
test3: (undefined) external _foo_barSuffix (from libfoo_barSuffix)
test3: 0000000100000e50 (__TEXT,__text) external _main
test3: (undefined) external _qt (from QT)
test3: (undefined) external _qtPath (from QTPath)
test3: (undefined) external _x (from libx)