[ELF][test] Reorganize "TLS attribute mismatch" tests

[MaskRay]

Accidentally opened.

lld/ELF/Symbols.h

 }
 
 // replace() replaces "this" object with a given symbol by memcpy'ing
 // it over to "this". This function is called as a result of name
 // resolution, e.g. to replace an undefind symbol with a defined symbol.
 void Symbol::replace(const Symbol &newSym) {
   using llvm::ELF::STT_TLS;
 
-  // Symbols representing thread-local variables must be referenced by
-  // TLS-aware relocations, and non-TLS symbols must be reference by
-  // non-TLS relocations, so there's a clear distinction between TLS
-  // and non-TLS symbols. It is an error if the same symbol is defined
-  // as a TLS symbol in one file and as a non-TLS symbol in other file.
-  if (symbolKind != PlaceholderKind && !isLazy() && !newSym.isLazy() &&
-      (type == STT_TLS) != (newSym.type == STT_TLS))
+  // st_value of STT_TLS represents the assigned offset, not the actual address
+  // which is used by STT_FUNC and STT_OBJECT. STT_TLS symbols can only be
+  // referenced by special TLS relocations. It is usually an error if a STT_TLS
+  // symbol is replaced by a non-STT_TLS symbol, vice versa. symbol in other
+  // file. There are two exceptions: (a) a STT_NOTYPE lazy/undefined symbol can
+  // be replaced by a STT_TLS symbol, (b) a STT_TLS undefined symbol can be
+  // replaced by a STT_NOTYPE lazy symbol.
+  if (symbolKind != PlaceholderKind && !newSym.isLazy() &&
+      (type == STT_TLS) != (newSym.type == STT_TLS) &&
+      type != llvm::ELF::STT_NOTYPE)
     error("TLS attribute mismatch: " + toString(*this) + "\n>>> defined in " +
           toString(newSym.file) + "\n>>> defined in " + toString(file));
 
   Symbol old = *this;
   memcpy(this, &newSym, newSym.getSymbolSize());
 
   // old may be a placeholder. The referenced fields must be initialized in
   // SymbolTable::insert.

lld/test/ELF/Inputs/tls-mismatch.s

-.tbss
-.globl tlsvar
-tlsvar:
-  .space 4

lld/test/ELF/tls-archive.s

-// REQUIRES: x86
-// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t
-// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/tls-mismatch.s -o %t2
-// RUN: rm -f %t.a
-// RUN: llvm-ar cru %t.a %t2
-// RUN: ld.lld %t.a %t -o /dev/null
-
-.globl _start,tlsvar
-_start:
-  movq tlsvar@GOTTPOFF(%rip),%rdx

lld/test/ELF/tls-mismatch.s

-// REQUIRES: x86
-// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t
-// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/tls-mismatch.s -o %t2
-// RUN: not ld.lld %t %t2 -o /dev/null 2>&1 | FileCheck %s
-
-// CHECK: TLS attribute mismatch: tlsvar
-// CHECK: >>> defined in
-// CHECK: >>> defined in
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
+# RUN: echo 'movq tls1@GOTTPOFF(%rip), %rax' | llvm-mc -filetype=obj -triple=x86_64 - -o %t1.o
+# RUN: ld.lld %t1.o %t.o -o /dev/null
+# RUN: ld.lld %t.o %t1.o -o /dev/null
+# RUN: ld.lld --start-lib %t.o --end-lib %t1.o -o /dev/null
+# RUN: ld.lld %t1.o --start-lib %t.o --end-lib -o /dev/null
 
-.globl _start,tlsvar
+## The TLS definition mismatches a non-TLS reference.
+# RUN: echo '.type tls1,@object; movq tls1,%rax' | llvm-mc -filetype=obj -triple=x86_64 - -o %t2.o
+# RUN: not ld.lld %t2.o %t.o -o /dev/null 2>&1 | FileCheck %s
+## We fail to flag the swapped case.
+# RUN: ld.lld %t.o %t2.o -o /dev/null
+
+## We fail to flag the STT_NOTYPE reference. This usually happens with hand-written
+## assembly because compiler-generated code properly sets symbol types.
+# RUN: echo 'movq tls1,%rax' | llvm-mc -filetype=obj -triple=x86_64 - -o %t3.o
+# RUN: ld.lld %t3.o %t.o -o /dev/null
+
+## Overriding a TLS definition with a non-TLS definition does not make sense.
+# RUN: not ld.lld --defsym tls1=42 %t.o -o /dev/null 2>&1 | FileCheck %s
+
+## Part of PR36049: This should probably be allowed.
+# RUN: not ld.lld --defsym tls1=tls2 %t.o -o /dev/null 2>&1 | FileCheck %s
+
+## An undefined symbol in module-level inline assembly of a bitcode file
+## is considered STT_NOTYPE. We should not error.
+# RUN: echo 'target triple = "x86_64-pc-linux-gnu" \
+# RUN:   target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" \
+# RUN:   module asm "movq tls1@GOTTPOFF(%rip), %rax"' | llvm-as - -o %t.bc
+# RUN: ld.lld %t.o %t.bc -o /dev/null
+# RUN: ld.lld %t.bc %t.o -o /dev/null
+
+# CHECK: error: TLS attribute mismatch: tls1
+
+.globl _start
 _start:
-  movl tlsvar,%edx
+  addl $1, %fs:tls1@TPOFF
+  addl $2, %fs:tls2@TPOFF
+
+.tbss
+.globl tls1, tls2
+  .space 8
+tls1:
+  .space 4
+tls2:
+  .space 4