From 5694dbccc3c8c778024fdfe3ff688cd838b45349 Mon Sep 17 00:00:00 2001
From: Wouter van Oortmerssen <aardappel@gmail.com>
Date: Thu, 21 Oct 2021 13:44:54 -0700
Subject: [PATCH] [WebAssembly] support Memory64 in target_features section

Differential Revision: https://reviews.llvm.org/D112266
---
 .../Target/WebAssembly/WebAssemblyAsmPrinter.cpp  |  9 +++++++++
 llvm/test/CodeGen/WebAssembly/memory64-feature.ll | 15 +++++++++++++++
 llvm/test/MC/WebAssembly/debug-info64.ll          |  6 ++++++
 3 files changed, 30 insertions(+)
 create mode 100644 llvm/test/CodeGen/WebAssembly/memory64-feature.ll

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
index 66acd3519623..3851300f615e 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
@@ -503,6 +503,15 @@ void WebAssemblyAsmPrinter::EmitTargetFeatures(Module &M) {
   // This pseudo-feature tells the linker whether shared memory would be safe
   EmitFeature("shared-mem");
 
+  // This is an "architecture", not a "feature", but we emit it as such for
+  // the benefit of tools like Binaryen and consistency with other producers.
+  // FIXME: Subtarget is null here, so can't Subtarget->hasAddr64() ?
+  if (M.getDataLayout().getMaxPointerSize() == 8) {
+    // Can't use EmitFeature since "wasm-feature-memory64" is not a module
+    // flag.
+    EmittedFeatures.push_back({wasm::WASM_FEATURE_PREFIX_USED, "memory64"});
+  }
+
   if (EmittedFeatures.size() == 0)
     return;
 
diff --git a/llvm/test/CodeGen/WebAssembly/memory64-feature.ll b/llvm/test/CodeGen/WebAssembly/memory64-feature.ll
new file mode 100644
index 000000000000..53fccfe08888
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/memory64-feature.ll
@@ -0,0 +1,15 @@
+; RUN: llc < %s | FileCheck %s
+
+; Test that wasm64 is properly emitted into the target features section
+
+target triple = "wasm64-unknown-unknown"
+
+define void @foo() {
+  ret void
+}
+
+; CHECK-LABEL: .custom_section.target_features
+; CHECK-NEXT: .int8 1
+; CHECK-NEXT: .int8 43
+; CHECK-NEXT: .int8 8
+; CHECK-NEXT: .ascii "memory64"
diff --git a/llvm/test/MC/WebAssembly/debug-info64.ll b/llvm/test/MC/WebAssembly/debug-info64.ll
index a8d9a24a1f2b..60fa0cbfe987 100644
--- a/llvm/test/MC/WebAssembly/debug-info64.ll
+++ b/llvm/test/MC/WebAssembly/debug-info64.ll
@@ -129,6 +129,12 @@
 ; CHECK-NEXT:     Offset: 1073
 ; CHECK-NEXT:     Name: producers
 ; CHECK-NEXT:   }
+; CHECK-NEXT:   Section {
+; CHECK-NEXT:     Type: CUSTOM (0x0)
+; CHECK-NEXT:     Size: 11
+; CHECK-NEXT:     Offset: 1166
+; CHECK-NEXT:     Name: target_features
+; CHECK-NEXT:   }
 ; CHECK-NEXT: ]
 ; CHECK-NEXT: Relocations [
 ; CHECK-NEXT:   Section (7) DATA {