[MC][WebAssembly] Error on data symbols in the text section.

Previously we had an assert but this can actually occur in valid user
code so we need to handle this in release builds too.

Differential Revision: https://reviews.llvm.org/D67997

llvm-svn: 372934

llvm/lib/MC/WasmObjectWriter.cpp

@@ -1350,7 +1350,9 @@ uint64_t WasmObjectWriter::writeObject(MCAssembler &Asm,
         report_fatal_error(".size expression must be evaluatable");
 
       auto &DataSection = static_cast<MCSectionWasm &>(WS.getSection());
-      assert(DataSection.isWasmData());
+      if (!DataSection.isWasmData())
+        report_fatal_error("data symbols must live in a data section: " +
+                           WS.getName());
 
       // For each data symbol, export it in the symtab as a reference to the
       // corresponding Wasm data segment.

llvm/test/MC/WebAssembly/data-symbol-in-text-section.ll

@@ -0,0 +1,13 @@
+; RUN: not llc -filetype=obj %s -o /dev/null 2>&1 | FileCheck %s
+; CHECK: data symbols must live in a data section: data_symbol
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+@data_symbol = constant [1024 x i32] zeroinitializer, section ".text", align 16
+
+define hidden i32 @main() local_unnamed_addr #0 {
+entry:
+  %0 = load i32, i32* getelementptr inbounds ([1024 x i32], [1024 x i32]* @data_symbol, i32 0, i32 10)
+  ret i32 %0
+}