[WebAssembly] Use __stack_pointer global when writing wasm binary
This ensures that symbolic relocations are generated for stack
pointer manipulations.
These relocations are of type R_WEBASSEMBLY_GLOBAL_INDEX_LEB.
This change also adds support for reading relocations of this
type in WasmObjectFile.cpp.
Since its a globally imported symbol this does mean that
the get_global/set_global instruction won't be valid until
the objects are linked that global used in no longer an
imported global.
Differential Revision: https://reviews.llvm.org/D34172
llvm-svn: 305616
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
index c56c591..3e3b52f 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
@@ -36,7 +36,6 @@
namespace {
class WebAssemblyMCCodeEmitter final : public MCCodeEmitter {
const MCInstrInfo &MCII;
- MCContext &Ctx;
// Implementation generated by tablegen.
uint64_t getBinaryCodeForInstr(const MCInst &MI,
@@ -48,14 +47,12 @@
const MCSubtargetInfo &STI) const override;
public:
- WebAssemblyMCCodeEmitter(const MCInstrInfo &mcii, MCContext &ctx)
- : MCII(mcii), Ctx(ctx) {}
+ WebAssemblyMCCodeEmitter(const MCInstrInfo &mcii) : MCII(mcii) {}
};
} // end anonymous namespace
-MCCodeEmitter *llvm::createWebAssemblyMCCodeEmitter(const MCInstrInfo &MCII,
- MCContext &Ctx) {
- return new WebAssemblyMCCodeEmitter(MCII, Ctx);
+MCCodeEmitter *llvm::createWebAssemblyMCCodeEmitter(const MCInstrInfo &MCII) {
+ return new WebAssemblyMCCodeEmitter(MCII);
}
void WebAssemblyMCCodeEmitter::encodeInstruction(
@@ -89,11 +86,7 @@
} else if (Info.OperandType == WebAssembly::OPERAND_I64IMM) {
encodeSLEB128(int64_t(MO.getImm()), OS);
} else if (Info.OperandType == WebAssembly::OPERAND_GLOBAL) {
- Fixups.push_back(MCFixup::create(
- OS.tell() - Start, MCConstantExpr::create(MO.getImm(), Ctx),
- MCFixupKind(WebAssembly::fixup_code_global_index), MI.getLoc()));
- ++MCNumFixups;
- encodeULEB128(uint64_t(MO.getImm()), OS);
+ llvm_unreachable("wasm globals should only be accessed symbolicly");
} else if (Info.OperandType == WebAssembly::OPERAND_SIGNATURE) {
encodeSLEB128(int64_t(MO.getImm()), OS);
} else {
@@ -135,6 +128,9 @@
Info.OperandType == WebAssembly::OPERAND_TYPEINDEX) {
FixupKind = MCFixupKind(WebAssembly::fixup_code_uleb128_i32);
PaddedSize = 5;
+ } else if (Info.OperandType == WebAssembly::OPERAND_GLOBAL) {
+ FixupKind = MCFixupKind(WebAssembly::fixup_code_global_index);
+ PaddedSize = 5;
} else {
llvm_unreachable("unexpected symbolic operand kind");
}