[WebAssembly] Initial linking metadata support
Add support for the new relocations and linking metadata section support in
https://github.com/WebAssembly/tool-conventions/blob/master/Linking.md. In
particular, this allows LLVM to indicate which variable is the stack pointer,
so that it can be linked with other objects.
This also adds support for emitting type relocations for call_indirect
instructions.
Right now, this is mainly tested by using wabt and hexdump to examine the
output on selected testcases. We'll add more tests as the design stablizes
and more of the pieces are in place.
llvm-svn: 299141
diff --git a/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp b/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
index 0af13cf..26461e2 100644
--- a/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
+++ b/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
@@ -242,3 +242,18 @@
llvm_unreachable("unsupported type");
}
}
+
+const char *llvm::WebAssembly::TypeToString(wasm::ValType Type) {
+ switch (Type) {
+ case wasm::ValType::I32:
+ return "i32";
+ case wasm::ValType::I64:
+ return "i64";
+ case wasm::ValType::F32:
+ return "f32";
+ case wasm::ValType::F64:
+ return "f64";
+ default:
+ llvm_unreachable("unsupported type");
+ }
+}
diff --git a/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.h b/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.h
index d11f99c..c615872 100644
--- a/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.h
+++ b/llvm/lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.h
@@ -18,6 +18,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineValueType.h"
#include "llvm/MC/MCInstPrinter.h"
+#include "llvm/Support/Wasm.h"
namespace llvm {
@@ -50,6 +51,7 @@
namespace WebAssembly {
const char *TypeToString(MVT Ty);
+const char *TypeToString(wasm::ValType Type);
} // end namespace WebAssembly
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.cpp
index f3b6b10..ad59f2f 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.cpp
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.cpp
@@ -25,7 +25,6 @@
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormattedStream.h"
-#include "llvm/Support/Wasm.h"
using namespace llvm;
WebAssemblyTargetStreamer::WebAssemblyTargetStreamer(MCStreamer &S)
@@ -88,13 +87,31 @@
}
}
-void WebAssemblyTargetAsmStreamer::emitGlobal(ArrayRef<MVT> Types) {
- if (!Types.empty()) {
+void WebAssemblyTargetAsmStreamer::emitGlobal(
+ ArrayRef<wasm::Global> Globals) {
+ if (!Globals.empty()) {
OS << "\t.globalvar \t";
- PrintTypes(OS, Types);
+
+ bool First = true;
+ for (const wasm::Global &G : Globals) {
+ if (First)
+ First = false;
+ else
+ OS << ", ";
+ OS << WebAssembly::TypeToString(G.Type);
+ if (!G.InitialModule.empty())
+ OS << '=' << G.InitialModule << ':' << G.InitialName;
+ else
+ OS << '=' << G.InitialValue;
+ }
+ OS << '\n';
}
}
+void WebAssemblyTargetAsmStreamer::emitStackPointer(uint32_t Index) {
+ OS << "\t.stack_pointer\t" << Index << '\n';
+}
+
void WebAssemblyTargetAsmStreamer::emitEndFunc() { OS << "\t.endfunc\n"; }
void WebAssemblyTargetAsmStreamer::emitIndirectFunctionType(
@@ -135,10 +152,16 @@
emitValueType(WebAssembly::toValType(Type));
}
-void WebAssemblyTargetELFStreamer::emitGlobal(ArrayRef<MVT> Types) {
+void WebAssemblyTargetELFStreamer::emitGlobal(
+ ArrayRef<wasm::Global> Globals) {
llvm_unreachable(".globalvar encoding not yet implemented");
}
+void WebAssemblyTargetELFStreamer::emitStackPointer(
+ uint32_t Index) {
+ llvm_unreachable(".stack_pointer encoding not yet implemented");
+}
+
void WebAssemblyTargetELFStreamer::emitEndFunc() {
Streamer.EmitIntValue(WebAssembly::End, 1);
}
@@ -190,15 +213,36 @@
}
}
-void WebAssemblyTargetWasmStreamer::emitGlobal(ArrayRef<MVT> Types) {
+void WebAssemblyTargetWasmStreamer::emitGlobal(
+ ArrayRef<wasm::Global> Globals) {
// Encode the globals use by the funciton into the special .global_variables
// section. This will later be decoded and turned into contents for the
// Globals Section.
Streamer.PushSection();
Streamer.SwitchSection(Streamer.getContext()
.getWasmSection(".global_variables", 0, 0));
- for (MVT Ty : Types)
- Streamer.EmitIntValue(int64_t(WebAssembly::toValType(Ty)), 1);
+ for (const wasm::Global &G : Globals) {
+ Streamer.EmitIntValue(int32_t(G.Type), 1);
+ Streamer.EmitIntValue(G.Mutable, 1);
+ if (G.InitialModule.empty()) {
+ Streamer.EmitIntValue(0, 1); // indicate that we have an int value
+ Streamer.EmitSLEB128IntValue(0);
+ } else {
+ Streamer.EmitIntValue(1, 1); // indicate that we have a module import
+ Streamer.EmitBytes(G.InitialModule);
+ Streamer.EmitIntValue(0, 1); // nul-terminate
+ Streamer.EmitBytes(G.InitialName);
+ Streamer.EmitIntValue(0, 1); // nul-terminate
+ }
+ }
+ Streamer.PopSection();
+}
+
+void WebAssemblyTargetWasmStreamer::emitStackPointer(uint32_t Index) {
+ Streamer.PushSection();
+ Streamer.SwitchSection(Streamer.getContext()
+ .getWasmSection(".stack_pointer", 0, 0));
+ Streamer.EmitIntValue(Index, 4);
Streamer.PopSection();
}
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.h b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.h
index bb9a9c9..68d6747 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.h
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyTargetStreamer.h
@@ -38,7 +38,9 @@
/// .local
virtual void emitLocal(ArrayRef<MVT> Types) = 0;
/// .globalvar
- virtual void emitGlobal(ArrayRef<MVT> Types) = 0;
+ virtual void emitGlobal(ArrayRef<wasm::Global> Globals) = 0;
+ /// .stack_pointer
+ virtual void emitStackPointer(uint32_t Index) = 0;
/// .endfunc
virtual void emitEndFunc() = 0;
/// .functype
@@ -66,7 +68,8 @@
void emitParam(MCSymbol *Symbol, ArrayRef<MVT> Types) override;
void emitResult(MCSymbol *Symbol, ArrayRef<MVT> Types) override;
void emitLocal(ArrayRef<MVT> Types) override;
- void emitGlobal(ArrayRef<MVT> Types) override;
+ void emitGlobal(ArrayRef<wasm::Global> Globals) override;
+ void emitStackPointer(uint32_t Index) override;
void emitEndFunc() override;
void emitIndirectFunctionType(StringRef name,
SmallVectorImpl<MVT> &Params,
@@ -83,7 +86,8 @@
void emitParam(MCSymbol *Symbol, ArrayRef<MVT> Types) override;
void emitResult(MCSymbol *Symbol, ArrayRef<MVT> Types) override;
void emitLocal(ArrayRef<MVT> Types) override;
- void emitGlobal(ArrayRef<MVT> Types) override;
+ void emitGlobal(ArrayRef<wasm::Global> Globals) override;
+ void emitStackPointer(uint32_t Index) override;
void emitEndFunc() override;
void emitIndirectFunctionType(StringRef name,
SmallVectorImpl<MVT> &Params,
@@ -100,7 +104,8 @@
void emitParam(MCSymbol *Symbol, ArrayRef<MVT> Types) override;
void emitResult(MCSymbol *Symbol, ArrayRef<MVT> Types) override;
void emitLocal(ArrayRef<MVT> Types) override;
- void emitGlobal(ArrayRef<MVT> Types) override;
+ void emitGlobal(ArrayRef<wasm::Global> Globals) override;
+ void emitStackPointer(uint32_t Index) override;
void emitEndFunc() override;
void emitIndirectFunctionType(StringRef name,
SmallVectorImpl<MVT> &Params,
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
index c272eb4..d9c2dba 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
@@ -97,6 +97,8 @@
if (!TM.getTargetTriple().isOSBinFormatELF()) {
MachineModuleInfoWasm &MMIW = MMI->getObjFileInfo<MachineModuleInfoWasm>();
getTargetStreamer()->emitGlobal(MMIW.getGlobals());
+ if (MMIW.hasStackPointerGlobal())
+ getTargetStreamer()->emitStackPointer(MMIW.getStackPointerGlobal());
}
}
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
index 8b25285..4209bc3 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
@@ -192,7 +192,16 @@
auto &MMIW = MF.getMMI().getObjFileInfo<MachineModuleInfoWasm>();
if (!MMIW.hasStackPointerGlobal()) {
MMIW.setStackPointerGlobal(MMIW.getGlobals().size());
- MMIW.addGlobal(MVT::i32);
+
+ // Create the stack-pointer global. For now, just use the
+ // Emscripten/Binaryen ABI names.
+ wasm::Global G;
+ G.Type = wasm::ValType::I32;
+ G.Mutable = true;
+ G.InitialValue = 0;
+ G.InitialModule = "env";
+ G.InitialName = "STACKTOP";
+ MMIW.addGlobal(G);
}
BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::GET_GLOBAL_I32), SPReg)
.addImm(MMIW.getStackPointerGlobal());