[WebAssembly] Track frame registers through VReg and local allocation
This change has 2 components:
Target-independent: add a method getDwarfFrameBase to TargetFrameLowering. It
describes how the Dwarf frame base will be encoded. That can be a register (the
default), the CFA (which replaces NVPTX-specific logic in DwarfCompileUnit), or
a DW_OP_WASM_location descriptr.
WebAssembly: Allow WebAssemblyFunctionInfo::getFrameRegister to return the
correct virtual register instead of FP32/SP32 after WebAssemblyReplacePhysRegs
has run. Make WebAssemblyExplicitLocals store the local it allocates for the
frame register. Use this local information to implement getDwarfFrameBase
The result is that the DW_AT_frame_base attribute is correctly encoded for each
subprogram, and each param and local variable has a correct DW_AT_location that
uses DW_OP_fbreg to refer to the frame base.
This is a reland of rG3a05c3969c18 with fixes for the expensive-checks
and Windows builds
Differential Revision: https://reviews.llvm.org/D71681
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
index fdc0f56..42fe8e5 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
@@ -44,6 +44,7 @@
bool hasFP(const MachineFunction &MF) const override;
bool hasReservedCallFrame(const MachineFunction &MF) const override;
+ DwarfFrameBase getDwarfFrameBase(const MachineFunction &MF) const override;
bool needsPrologForEH(const MachineFunction &MF) const;