[llvm] 3b1f17c - [JITLink][ELF/x86-64] Add support for weak and hidden symbols.
Lang Hames via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 22 01:52:17 PST 2021
Author: Lang Hames
Date: 2021-01-22T20:51:11+11:00
New Revision: 3b1f17ca5498e17655ce531f13f1e8c2cf37058d
URL: https://github.com/llvm/llvm-project/commit/3b1f17ca5498e17655ce531f13f1e8c2cf37058d
DIFF: https://github.com/llvm/llvm-project/commit/3b1f17ca5498e17655ce531f13f1e8c2cf37058d.diff
LOG: [JITLink][ELF/x86-64] Add support for weak and hidden symbols.
Added:
llvm/test/ExecutionEngine/JITLink/X86/ELF_weak_definitions.s
llvm/test/ExecutionEngine/JITLink/X86/Inputs/ELF_weak_defs_extra.s
Modified:
llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp
llvm/lib/ExecutionEngine/JITLink/JITLink.cpp
Removed:
################################################################################
diff --git a/llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp b/llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp
index 244975f4a51a..0ca2130150a6 100644
--- a/llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp
+++ b/llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp
@@ -544,7 +544,6 @@ class ELFLinkGraphBuilder_x86_64 {
// Type != ELF::STT_COMMON) {
// continue;
// }
- std::pair<Linkage, Scope> bindings;
auto Name = SymRef.getName(*StringTable);
// I am not sure on If this is going to hold as an invariant. Revisit.
if (!Name)
@@ -560,11 +559,43 @@ class ELFLinkGraphBuilder_x86_64 {
continue;
}
- // TODO: weak and hidden
- if (SymRef.isExternal())
- bindings = {Linkage::Strong, Scope::Default};
- else
- bindings = {Linkage::Strong, Scope::Local};
+ // Map Visibility and Binding to Scope and Linkage:
+ Linkage L = Linkage::Strong;
+ Scope S = Scope::Default;
+
+ switch (SymRef.getBinding()) {
+ case ELF::STB_LOCAL:
+ S = Scope::Local;
+ break;
+ case ELF::STB_GLOBAL:
+ // Nothing to do here.
+ break;
+ case ELF::STB_WEAK:
+ L = Linkage::Weak;
+ break;
+ default:
+ return make_error<StringError>("Unrecognized symbol binding for " +
+ *Name,
+ inconvertibleErrorCode());
+ }
+
+ switch (SymRef.getVisibility()) {
+ case ELF::STV_DEFAULT:
+ case ELF::STV_PROTECTED:
+ // FIXME: Make STV_DEFAULT symbols pre-emptible? This probably needs
+ // Orc support.
+ // Otherwise nothing to do here.
+ break;
+ case ELF::STV_HIDDEN:
+ // Default scope -> Hidden scope. No effect on local scope.
+ if (S == Scope::Default)
+ S = Scope::Hidden;
+ break;
+ case ELF::STV_INTERNAL:
+ return make_error<StringError>("Unrecognized symbol visibility for " +
+ *Name,
+ inconvertibleErrorCode());
+ }
if (SymRef.isDefined() &&
(Type == ELF::STT_FUNC || Type == ELF::STT_OBJECT ||
@@ -591,17 +622,17 @@ class ELFLinkGraphBuilder_x86_64 {
return make_error<llvm::StringError>(
"Section has no block", llvm::inconvertibleErrorCode());
- auto B = *bs.begin();
+ auto *B = *bs.begin();
LLVM_DEBUG({ dbgs() << " " << *Name << " at index " << SymbolIndex << "\n"; });
if (SymRef.getType() == ELF::STT_SECTION)
*Name = *sectName;
- auto &S = G->addDefinedSymbol(
- *B, SymRef.getValue(), *Name, SymRef.st_size, bindings.first,
- bindings.second, SymRef.getType() == ELF::STT_FUNC, false);
- JITSymbolTable[SymbolIndex] = &S;
+ auto &Sym = G->addDefinedSymbol(
+ *B, SymRef.getValue(), *Name, SymRef.st_size, L, S,
+ SymRef.getType() == ELF::STT_FUNC, false);
+ JITSymbolTable[SymbolIndex] = &Sym;
} else if (SymRef.isUndefined() && SymRef.isExternal()) {
- auto &S = G->addExternalSymbol(*Name, SymRef.st_size, bindings.first);
- JITSymbolTable[SymbolIndex] = &S;
+ auto &Sym = G->addExternalSymbol(*Name, SymRef.st_size, L);
+ JITSymbolTable[SymbolIndex] = &Sym;
} else
LLVM_DEBUG({
dbgs()
diff --git a/llvm/lib/ExecutionEngine/JITLink/JITLink.cpp b/llvm/lib/ExecutionEngine/JITLink/JITLink.cpp
index 41b5423dc335..93dfba9c759b 100644
--- a/llvm/lib/ExecutionEngine/JITLink/JITLink.cpp
+++ b/llvm/lib/ExecutionEngine/JITLink/JITLink.cpp
@@ -64,7 +64,7 @@ const char *getGenericEdgeKindName(Edge::Kind K) {
case Edge::KeepAlive:
return "Keep-Alive";
default:
- llvm_unreachable("Unrecognized relocation kind");
+ return "<Unrecognized edge kind>";
}
}
diff --git a/llvm/test/ExecutionEngine/JITLink/X86/ELF_weak_definitions.s b/llvm/test/ExecutionEngine/JITLink/X86/ELF_weak_definitions.s
new file mode 100644
index 000000000000..9085f42098db
--- /dev/null
+++ b/llvm/test/ExecutionEngine/JITLink/X86/ELF_weak_definitions.s
@@ -0,0 +1,52 @@
+# RUN: rm -rf %t && mkdir -p %t
+# RUN: llvm-mc -triple x86_64-pc-linux-gnu -filetype=obj \
+# RUN: -o %t/ELF_weak_defs_extra.o %S/Inputs/ELF_weak_defs_extra.s
+# RUN: llvm-mc -triple x86_64-pc-linux-gnu -filetype=obj \
+# RUN: -o %t/ELF_weak_definitions.o %s
+# RUN: llvm-jitlink -noexec -check=%s %t/ELF_weak_definitions.o \
+# RUN: %t/ELF_weak_defs_extra.o
+#
+# Check that objects linked separately agree on the address of weak symbols.
+#
+# jitlink-check: *{8}WeakDefAddrInThisFile = *{8}WeakDefAddrInExtraFile
+
+ .text
+ .file "ELF_weak_definitions.c"
+ .globl main
+ .p2align 4, 0x90
+ .type main, at function
+main:
+ movq WeakDef at GOTPCREL(%rip), %rax
+ movl (%rax), %eax
+ retq
+.Lfunc_end0:
+ .size main, .Lfunc_end0-main
+
+ .type WeakDef, at object
+ .data
+ .weak WeakDef
+ .p2align 2
+WeakDef:
+ .long 1
+ .size WeakDef, 4
+
+ .type WeakDefAddrInThisFile, at object
+ .globl WeakDefAddrInThisFile
+ .p2align 3
+WeakDefAddrInThisFile:
+ .quad WeakDef
+ .size WeakDefAddrInThisFile, 8
+
+
+ .type extra_file_anchor, at object
+ .globl extra_file_anchor
+ .p2align 3
+extra_file_anchor:
+ .quad WeakDefAddrInExtraFile
+ .size extra_file_anchor, 8
+
+ .ident "clang version 10.0.0-4ubuntu1 "
+ .section ".note.GNU-stack","", at progbits
+ .addrsig
+ .addrsig_sym WeakDef
+ .addrsig_sym WeakDefAddrInExtraFile
diff --git a/llvm/test/ExecutionEngine/JITLink/X86/Inputs/ELF_weak_defs_extra.s b/llvm/test/ExecutionEngine/JITLink/X86/Inputs/ELF_weak_defs_extra.s
new file mode 100644
index 000000000000..aa696dd50817
--- /dev/null
+++ b/llvm/test/ExecutionEngine/JITLink/X86/Inputs/ELF_weak_defs_extra.s
@@ -0,0 +1,24 @@
+# Supplies a weak def, WeakDef, and a pointer holding its address,
+# WeakDefAddrInExtraFile.
+
+ .text
+ .file "ELF_weak_defs_extra.c"
+ .type WeakDef, at object
+ .data
+ .weak WeakDef
+ .p2align 2
+WeakDef:
+ .long 2
+ .size WeakDef, 4
+
+ .type WeakDefAddrInExtraFile, at object
+ .globl WeakDefAddrInExtraFile
+ .p2align 3
+WeakDefAddrInExtraFile:
+ .quad WeakDef
+ .size WeakDefAddrInExtraFile, 8
+
+ .ident "clang version 10.0.0-4ubuntu1 "
+ .section ".note.GNU-stack","", at progbits
+ .addrsig
+ .addrsig_sym WeakDef
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