tms34010: fail loudly on non-GSPA globals

emitGlobalVariable handled only zero-initialized .bss objects and let
initialized globals, string literals and constant/private data fall
through to the generic ELF .data/.rodata/.asciz printer, which GSPA
rejects.  Reject every non-null initializer and private/constant data
with a fatal error, and add m1-data/m1-string negative tests.

llvm/lib/Target/TMS34010/TMS34010AsmPrinter.cpp

@@ -19,6 +19,7 @@
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 
 using namespace llvm;
 
@@ -49,9 +50,18 @@ void TMS34010AsmPrinter::emitInstruction(const MachineInstr *MI) {
 }
 
 void TMS34010AsmPrinter::emitGlobalVariable(const GlobalVariable *GV) {
+  // External declarations need no output in GSPA.
+  if (GV->isDeclaration())
+    return;
+
   // GSPA has no .comm/.local directives; a zero-initialized object is one
-  // .bss line.  Sizes and alignment in GSPA are in bits.
-  if (GV->hasInitializer() && GV->getInitializer()->isNullValue()) {
+  // .bss line.  Sizes and alignment in GSPA are in bits.  Anything else
+  // (initialized data, string literals, constant/private data) would fall
+  // through to the generic ELF .data/.rodata/.p2align/.asciz printer, which
+  // GSPA rejects; fail loudly instead.
+  if (GV->hasInitializer() && GV->getInitializer()->isNullValue() &&
+      !GV->isConstant() && !GV->hasPrivateLinkage() &&
+      GV->getSection().empty() && !GV->isThreadLocal()) {
     const DataLayout &DL = GV->getParent()->getDataLayout();
     Align Alignment = getGVAlignment(GV, DL, GV->getAlign().valueOrOne());
     uint64_t SizeBits =
@@ -64,7 +74,9 @@ void TMS34010AsmPrinter::emitGlobalVariable(const GlobalVariable *GV) {
     return;
   }
 
-  AsmPrinter::emitGlobalVariable(GV);
+  report_fatal_error(
+      "M1 supports only zero-initialized globals; .data/string literals are M2",
+      false);
 }
 
 char TMS34010AsmPrinter::ID = 0;

llvm/test/CodeGen/TMS34010/m1-data.ll

@@ -0,0 +1,7 @@
+; RUN: not llc -march=tms34010 -O0 -filetype=asm < %s 2>&1 | FileCheck %s
+; RUN: not llc -march=tms34010 -O2 -filetype=asm < %s 2>&1 | FileCheck %s
+;
+; GSPA has no .data/.p2align directives.  An initialized global used to fall
+; through to the generic ELF asm printer; it must fail loudly instead.
+; CHECK: M1 supports only zero-initialized globals; .data/string literals are M2
+@x = global i32 42

llvm/test/CodeGen/TMS34010/m1-string.ll

@@ -0,0 +1,12 @@
+; RUN: not llc -march=tms34010 -O0 -filetype=asm < %s 2>&1 | FileCheck %s
+; RUN: not llc -march=tms34010 -O2 -filetype=asm < %s 2>&1 | FileCheck %s
+;
+; A string literal is a private constant with a non-null initializer.  It
+; used to print .rodata/.asciz, which GSPA rejects; it must fail loudly.
+; CHECK: M1 supports only zero-initialized globals; .data/string literals are M2
+@.str = private unnamed_addr constant [6 x i8] c"hello\00", align 1
+
+define ptr @str() {
+entry:
+  ret ptr @.str
+}