[lld] r361635 - [WebAssembly] Add support for -emit-relocs
Sam Clegg via llvm-commits
llvm-commits at lists.llvm.org
Fri May 24 06:28:27 PDT 2019
Author: sbc
Date: Fri May 24 06:28:27 2019
New Revision: 361635
URL: http://llvm.org/viewvc/llvm-project?rev=361635&view=rev
Log:
[WebAssembly] Add support for -emit-relocs
This can be useful for post-link tools and for testing. Sometimes
it can be useful to produces a regular executable but with relocations
preserved.
Differential Revision: https://reviews.llvm.org/D62378
Added:
lld/trunk/test/wasm/emit-relocs.ll
Modified:
lld/trunk/wasm/Config.h
lld/trunk/wasm/Driver.cpp
lld/trunk/wasm/Options.td
lld/trunk/wasm/SyntheticSections.h
lld/trunk/wasm/Writer.cpp
Added: lld/trunk/test/wasm/emit-relocs.ll
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/wasm/emit-relocs.ll?rev=361635&view=auto
==============================================================================
--- lld/trunk/test/wasm/emit-relocs.ll (added)
+++ lld/trunk/test/wasm/emit-relocs.ll Fri May 24 06:28:27 2019
@@ -0,0 +1,39 @@
+; RUN: llc -filetype=obj %s -o %t.o
+; RUN: llc -filetype=obj %p/Inputs/ret32.ll -o %t.ret32.o
+; RUN: wasm-ld --emit-relocs -o %t.wasm %t.o %t.ret32.o
+; RUN: obj2yaml %t.wasm | FileCheck %s
+
+target triple = "wasm32-unknown-unknown"
+
+declare i32 @ret32(float)
+
+define void @unused_function() {
+ ret void
+}
+
+define hidden void @_start() local_unnamed_addr #0 {
+entry:
+ call i32 @ret32(float 0.0)
+ ret void
+}
+
+; CHECK: - Type: CODE
+; CHECK-NEXT: Relocations:
+; CHECK-NEXT: - Type: R_WASM_FUNCTION_INDEX_LEB
+; CHECK-NEXT: Index: 1
+; CHECK-NEXT: Offset: 0x00000009
+
+; CHECK: - Type: CUSTOM
+; CHECK-NEXT: Name: linking
+; CHECK-NEXT: Version: 2
+; CHECK-NEXT: SymbolTable:
+; CHECK-NEXT: - Index: 0
+; CHECK-NEXT: Kind: FUNCTION
+; CHECK-NEXT: Name: _start
+; CHECK-NEXT: Flags: [ ]
+; CHECK-NEXT: Function: 0
+; CHECK-NEXT: - Index: 1
+; CHECK-NEXT: Kind: FUNCTION
+; CHECK-NEXT: Name: ret32
+; CHECK-NEXT: Flags: [ VISIBILITY_HIDDEN ]
+; CHECK-NEXT: Function: 1
Modified: lld/trunk/wasm/Config.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/Config.h?rev=361635&r1=361634&r2=361635&view=diff
==============================================================================
--- lld/trunk/wasm/Config.h (original)
+++ lld/trunk/wasm/Config.h Fri May 24 06:28:27 2019
@@ -27,6 +27,7 @@ struct Configuration {
bool CompressRelocations;
bool Demangle;
bool DisableVerify;
+ bool EmitRelocs;
bool ExportAll;
bool ExportDynamic;
bool ExportTable;
Modified: lld/trunk/wasm/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/Driver.cpp?rev=361635&r1=361634&r2=361635&view=diff
==============================================================================
--- lld/trunk/wasm/Driver.cpp (original)
+++ lld/trunk/wasm/Driver.cpp Fri May 24 06:28:27 2019
@@ -302,6 +302,7 @@ static void readConfigs(opt::InputArgLis
Config->CompressRelocations = Args.hasArg(OPT_compress_relocations);
Config->Demangle = Args.hasFlag(OPT_demangle, OPT_no_demangle, true);
Config->DisableVerify = Args.hasArg(OPT_disable_verify);
+ Config->EmitRelocs = Args.hasArg(OPT_emit_relocs);
Config->Entry = getEntry(Args);
Config->ExportAll = Args.hasArg(OPT_export_all);
Config->ExportDynamic = Args.hasFlag(OPT_export_dynamic,
Modified: lld/trunk/wasm/Options.td
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/Options.td?rev=361635&r1=361634&r2=361635&view=diff
==============================================================================
--- lld/trunk/wasm/Options.td (original)
+++ lld/trunk/wasm/Options.td Fri May 24 06:28:27 2019
@@ -31,6 +31,8 @@ defm demangle: B<"demangle",
"Demangle symbol names",
"Do not demangle symbol names">;
+def emit_relocs: F<"emit-relocs">, HelpText<"Generate relocations in output">;
+
defm export_dynamic: B<"export-dynamic",
"Put symbols in the dynamic symbol table",
"Do not put symbols in the dynamic symbol table (default)">;
Modified: lld/trunk/wasm/SyntheticSections.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/SyntheticSections.h?rev=361635&r1=361634&r2=361635&view=diff
==============================================================================
--- lld/trunk/wasm/SyntheticSections.h (original)
+++ lld/trunk/wasm/SyntheticSections.h Fri May 24 06:28:27 2019
@@ -246,7 +246,9 @@ public:
const std::vector<OutputSegment *> &DataSegments)
: SyntheticSection(llvm::wasm::WASM_SEC_CUSTOM, "linking"),
InitFunctions(InitFunctions), DataSegments(DataSegments) {}
- bool isNeeded() const override { return Config->Relocatable; }
+ bool isNeeded() const override {
+ return Config->Relocatable || Config->EmitRelocs;
+ }
void writeBody() override;
void addToSymtab(Symbol *Sym);
Modified: lld/trunk/wasm/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/Writer.cpp?rev=361635&r1=361634&r2=361635&view=diff
==============================================================================
--- lld/trunk/wasm/Writer.cpp (original)
+++ lld/trunk/wasm/Writer.cpp Fri May 24 06:28:27 2019
@@ -129,7 +129,7 @@ void Writer::createCustomSections() {
LLVM_DEBUG(dbgs() << "createCustomSection: " << Name << "\n");
OutputSection *Sec = make<CustomSection>(Name, Pair.second);
- if (Config->Relocatable) {
+ if (Config->Relocatable || Config->EmitRelocs) {
auto *Sym = make<OutputSectionSymbol>(Sec);
Out.LinkingSec->addToSymtab(Sym);
Sec->SectionSym = Sym;
@@ -330,7 +330,7 @@ void Writer::addSections() {
createCustomSections();
addSection(Out.LinkingSec);
- if (Config->Relocatable) {
+ if (Config->EmitRelocs || Config->Relocatable) {
createRelocSections();
}
@@ -493,17 +493,17 @@ void Writer::calculateExports() {
}
void Writer::populateSymtab() {
- if (!Config->Relocatable)
+ if (!Config->Relocatable && !Config->EmitRelocs)
return;
for (Symbol *Sym : Symtab->getSymbols())
- if (Sym->IsUsedInRegularObj)
+ if (Sym->IsUsedInRegularObj && Sym->isLive())
Out.LinkingSec->addToSymtab(Sym);
for (ObjFile *File : Symtab->ObjectFiles) {
LLVM_DEBUG(dbgs() << "Local symtab entries: " << File->getName() << "\n");
for (Symbol *Sym : File->getSymbols())
- if (Sym->isLocal() && !isa<SectionSymbol>(Sym))
+ if (Sym->isLocal() && !isa<SectionSymbol>(Sym) && Sym->isLive())
Out.LinkingSec->addToSymtab(Sym);
}
}
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