forked from OSchip/llvm-project
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 llvm-svn: 300205
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@ -126,6 +126,7 @@ public:
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using irsymtab::Symbol::getCommonSize;
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using irsymtab::Symbol::getCommonAlignment;
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using irsymtab::Symbol::getCOFFWeakExternalFallback;
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using irsymtab::Symbol::isExecutable;
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};
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/// A range over the symbols in this InputFile.
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@ -92,6 +92,7 @@ struct Symbol {
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FB_global,
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FB_format_specific,
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FB_unnamed_addr,
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FB_executable,
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};
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/// The index into the Uncommon table, or -1 if this symbol does not have an
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@ -166,6 +167,7 @@ struct Symbol {
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bool isGlobal() const { return (Flags >> S::FB_global) & 1; }
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bool isFormatSpecific() const { return (Flags >> S::FB_format_specific) & 1; }
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bool isUnnamedAddr() const { return (Flags >> S::FB_unnamed_addr) & 1; }
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bool isExecutable() const { return (Flags >> S::FB_executable) & 1; }
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uint64_t getCommonSize() const {
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assert(isCommon());
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@ -125,6 +125,8 @@ Error Builder::addSymbol(ModuleSymbolTable::Symbol Msym) {
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Sym.Flags |= 1 << storage::Symbol::FB_global;
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if (Flags & object::BasicSymbolRef::SF_FormatSpecific)
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Sym.Flags |= 1 << storage::Symbol::FB_format_specific;
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if (Flags & object::BasicSymbolRef::SF_Executable)
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Sym.Flags |= 1 << storage::Symbol::FB_executable;
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Sym.ComdatIndex = -1;
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auto *GV = Msym.dyn_cast<GlobalValue *>();
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@ -11,37 +11,42 @@ source_filename = "src.c"
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!0 = !{i32 6, !"Linker Options", !{!{!"/include:foo"}}}
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!llvm.module.flags = !{ !0 }
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; CHECK: H------ _g1
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; CHECK: D------X _fun
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define i32 @fun() {
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ret i32 0
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}
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; CHECK: H------- _g1
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@g1 = hidden global i32 0
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; CHECK: P------ _g2
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; CHECK: P------- _g2
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@g2 = protected global i32 0
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; CHECK: D------ _g3
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; CHECK: D------- _g3
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@g3 = global i32 0
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; CHECK: DU----- _g4
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; CHECK: DU------ _g4
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@g4 = external global i32
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; CHECK: D--W--- _g5
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; CHECK: D--W---- _g5
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@g5 = weak global i32 0
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; CHECK: D--W-O- _g6
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; CHECK: D--W-O-- _g6
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@g6 = linkonce_odr unnamed_addr global i32 0
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; CHECK: D-----T _g7
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; CHECK: D-----T- _g7
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@g7 = thread_local global i32 0
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; CHECK: D-C---- _g8
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; CHECK: D-C----- _g8
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; CHECK-NEXT: size 4 align 8
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@g8 = common global i32 0, align 8
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; CHECK: D------ _g9
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; CHECK: D------- _g9
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; CHECK-NEXT: comdat g9
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$g9 = comdat any
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@g9 = global i32 0, comdat
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; CHECK: D--WI-- _g10
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; CHECK: D--WI--- _g10
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; CHECK-NEXT: comdat g9
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; CHECK-NEXT: fallback _g9
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@g10 = weak alias i32, i32* @g9
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@ -317,18 +317,19 @@ static int dumpSymtab(int argc, char **argv) {
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PrintBool('I', Sym.isIndirect());
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PrintBool('O', Sym.canBeOmittedFromSymbolTable());
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PrintBool('T', Sym.isTLS());
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PrintBool('X', Sym.isExecutable());
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outs() << ' ' << Sym.getName() << '\n';
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if (Sym.isCommon())
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outs() << " size " << Sym.getCommonSize() << " align "
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outs() << " size " << Sym.getCommonSize() << " align "
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<< Sym.getCommonAlignment() << '\n';
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int Comdat = Sym.getComdatIndex();
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if (Comdat != -1)
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outs() << " comdat " << ComdatTable[Comdat] << '\n';
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outs() << " comdat " << ComdatTable[Comdat] << '\n';
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if (Sym.isWeak() && Sym.isIndirect())
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outs() << " fallback " << Sym.getCOFFWeakExternalFallback() << '\n';
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outs() << " fallback " << Sym.getCOFFWeakExternalFallback() << '\n';
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}
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outs() << '\n';
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