[llvm] r300205 - LTO: Pass SF_Executable flag through to InputFile::Symbol
Tobias Edler von Koch via llvm-commits
llvm-commits at lists.llvm.org
Thu Apr 13 09:24:15 PDT 2017
Author: tobiasvk
Date: Thu Apr 13 11:24:14 2017
New Revision: 300205
URL: http://llvm.org/viewvc/llvm-project?rev=300205&view=rev
Log:
LTO: Pass SF_Executable flag through to InputFile::Symbol
Summary:
The linker needs to be able to determine whether a symbol is text or data to
handle the case of a common being overridden by a strong definition in an
archive. If the archive contains a text member of the same name as the common,
that function is discarded. However, if the archive contains a data member of
the same name, that strong definition overrides the common. This is a behavior
of ld.bfd, which the Qualcomm linker also supports in LTO.
Here's a test case to illustrate:
####
cat > 1.c << \!
int blah;
!
cat > 2.c << \!
int blah() {
return 0;
}
!
cat > 3.c << \!
int blah = 20;
!
clang -c 1.c
clang -c 2.c
clang -c 3.c
ar cr lib.a 2.o 3.o
ld 1.o lib.a -t
####
The correct output is:
1.o
(lib.a)3.o
Thanks to Shankar Easwaran and Hemant Kulkarni for the test case!
Reviewers: mehdi_amini, rafael, pcc, davide
Reviewed By: pcc
Subscribers: davide, llvm-commits, inglorion
Differential Revision: https://reviews.llvm.org/D31901
Modified:
llvm/trunk/include/llvm/LTO/LTO.h
llvm/trunk/include/llvm/Object/IRSymtab.h
llvm/trunk/lib/Object/IRSymtab.cpp
llvm/trunk/test/LTO/Resolution/X86/symtab.ll
llvm/trunk/tools/llvm-lto2/llvm-lto2.cpp
Modified: llvm/trunk/include/llvm/LTO/LTO.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/LTO/LTO.h?rev=300205&r1=300204&r2=300205&view=diff
==============================================================================
--- llvm/trunk/include/llvm/LTO/LTO.h (original)
+++ llvm/trunk/include/llvm/LTO/LTO.h Thu Apr 13 11:24:14 2017
@@ -126,6 +126,7 @@ public:
using irsymtab::Symbol::getCommonSize;
using irsymtab::Symbol::getCommonAlignment;
using irsymtab::Symbol::getCOFFWeakExternalFallback;
+ using irsymtab::Symbol::isExecutable;
};
/// A range over the symbols in this InputFile.
Modified: llvm/trunk/include/llvm/Object/IRSymtab.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/IRSymtab.h?rev=300205&r1=300204&r2=300205&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Object/IRSymtab.h (original)
+++ llvm/trunk/include/llvm/Object/IRSymtab.h Thu Apr 13 11:24:14 2017
@@ -92,6 +92,7 @@ struct Symbol {
FB_global,
FB_format_specific,
FB_unnamed_addr,
+ FB_executable,
};
/// The index into the Uncommon table, or -1 if this symbol does not have an
@@ -166,6 +167,7 @@ struct Symbol {
bool isGlobal() const { return (Flags >> S::FB_global) & 1; }
bool isFormatSpecific() const { return (Flags >> S::FB_format_specific) & 1; }
bool isUnnamedAddr() const { return (Flags >> S::FB_unnamed_addr) & 1; }
+ bool isExecutable() const { return (Flags >> S::FB_executable) & 1; }
uint64_t getCommonSize() const {
assert(isCommon());
Modified: llvm/trunk/lib/Object/IRSymtab.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/IRSymtab.cpp?rev=300205&r1=300204&r2=300205&view=diff
==============================================================================
--- llvm/trunk/lib/Object/IRSymtab.cpp (original)
+++ llvm/trunk/lib/Object/IRSymtab.cpp Thu Apr 13 11:24:14 2017
@@ -125,6 +125,8 @@ Error Builder::addSymbol(ModuleSymbolTab
Sym.Flags |= 1 << storage::Symbol::FB_global;
if (Flags & object::BasicSymbolRef::SF_FormatSpecific)
Sym.Flags |= 1 << storage::Symbol::FB_format_specific;
+ if (Flags & object::BasicSymbolRef::SF_Executable)
+ Sym.Flags |= 1 << storage::Symbol::FB_executable;
Sym.ComdatIndex = -1;
auto *GV = Msym.dyn_cast<GlobalValue *>();
Modified: llvm/trunk/test/LTO/Resolution/X86/symtab.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/LTO/Resolution/X86/symtab.ll?rev=300205&r1=300204&r2=300205&view=diff
==============================================================================
--- llvm/trunk/test/LTO/Resolution/X86/symtab.ll (original)
+++ llvm/trunk/test/LTO/Resolution/X86/symtab.ll Thu Apr 13 11:24:14 2017
@@ -11,37 +11,42 @@ source_filename = "src.c"
!0 = !{i32 6, !"Linker Options", !{!{!"/include:foo"}}}
!llvm.module.flags = !{ !0 }
-; CHECK: H------ _g1
+; CHECK: D------X _fun
+define i32 @fun() {
+ ret i32 0
+}
+
+; CHECK: H------- _g1
@g1 = hidden global i32 0
-; CHECK: P------ _g2
+; CHECK: P------- _g2
@g2 = protected global i32 0
-; CHECK: D------ _g3
+; CHECK: D------- _g3
@g3 = global i32 0
-; CHECK: DU----- _g4
+; CHECK: DU------ _g4
@g4 = external global i32
-; CHECK: D--W--- _g5
+; CHECK: D--W---- _g5
@g5 = weak global i32 0
-; CHECK: D--W-O- _g6
+; CHECK: D--W-O-- _g6
@g6 = linkonce_odr unnamed_addr global i32 0
-; CHECK: D-----T _g7
+; CHECK: D-----T- _g7
@g7 = thread_local global i32 0
-; CHECK: D-C---- _g8
+; CHECK: D-C----- _g8
; CHECK-NEXT: size 4 align 8
@g8 = common global i32 0, align 8
-; CHECK: D------ _g9
+; CHECK: D------- _g9
; CHECK-NEXT: comdat g9
$g9 = comdat any
@g9 = global i32 0, comdat
-; CHECK: D--WI-- _g10
+; CHECK: D--WI--- _g10
; CHECK-NEXT: comdat g9
; CHECK-NEXT: fallback _g9
@g10 = weak alias i32, i32* @g9
Modified: llvm/trunk/tools/llvm-lto2/llvm-lto2.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-lto2/llvm-lto2.cpp?rev=300205&r1=300204&r2=300205&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-lto2/llvm-lto2.cpp (original)
+++ llvm/trunk/tools/llvm-lto2/llvm-lto2.cpp Thu Apr 13 11:24:14 2017
@@ -317,18 +317,19 @@ static int dumpSymtab(int argc, char **a
PrintBool('I', Sym.isIndirect());
PrintBool('O', Sym.canBeOmittedFromSymbolTable());
PrintBool('T', Sym.isTLS());
+ PrintBool('X', Sym.isExecutable());
outs() << ' ' << Sym.getName() << '\n';
if (Sym.isCommon())
- outs() << " size " << Sym.getCommonSize() << " align "
+ outs() << " size " << Sym.getCommonSize() << " align "
<< Sym.getCommonAlignment() << '\n';
int Comdat = Sym.getComdatIndex();
if (Comdat != -1)
- outs() << " comdat " << ComdatTable[Comdat] << '\n';
+ outs() << " comdat " << ComdatTable[Comdat] << '\n';
if (Sym.isWeak() && Sym.isIndirect())
- outs() << " fallback " << Sym.getCOFFWeakExternalFallback() << '\n';
+ outs() << " fallback " << Sym.getCOFFWeakExternalFallback() << '\n';
}
outs() << '\n';
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