Update documentation and add option to print address space names

Author: jurahul

llvm/docs/LangRef.rst

@@ -3331,7 +3331,7 @@ as follows:
 ``A<address space>``
     Specifies the address space of objects created by '``alloca``'.
     Defaults to the default address space of 0.
-``p[<flags>][<as>]:<size>:<abi>[:<pref>[:<idx>]]``
+``p[<flags>][<as>][(<name>)]:<size>:<abi>[:<pref>[:<idx>]]``
     This specifies the properties of a pointer in address space ``as``.
     The ``<size>`` parameter specifies the size of the bitwise representation.
     For :ref:`non-integral pointers <nointptrtype>` the representation size may
@@ -3350,7 +3350,11 @@ as follows:
     The optional ``<flags>`` are used to specify properties of pointers in this
     address space: the character ``u`` marks pointers as having an unstable
     representation, and ``e`` marks pointers having external state. See
-    :ref:`Non-Integral Pointer Types <nointptrtype>`.
+    :ref:`Non-Integral Pointer Types <nointptrtype>`. The ``<name>`` is an
+    optional name of that address space, surrounded by ``(`` and ``)``. If the
+    name is specified, it must be unique to that address space and cannot be
+    ``A``, ``G``, or ``P`` which are pre-defined names used to denote alloca,
+    global, and program address space respectively.
 
 ``i<size>:<abi>[:<pref>]``
     This specifies the alignment for an integer type of a given bit

llvm/lib/IR/AsmWriter.cpp

@@ -107,6 +107,11 @@ static cl::opt<bool> PreserveAssemblyUseListOrder(
     "preserve-ll-uselistorder", cl::Hidden, cl::init(false),
     cl::desc("Preserve use-list order when writing LLVM assembly."));
 
+static cl::opt<bool>
+    PrintSymbolicAddressSpace("print-sym-addr-space", cl::Hidden,
+                              cl::init(false),
+                              cl::desc("Print symbolic address space names"));
+
 // Make virtual table appear in this compilation unit.
 AssemblyAnnotationWriter::~AssemblyAnnotationWriter() = default;
 
@@ -638,7 +643,9 @@ static void printAddressSpace(const Module *M, unsigned AS, raw_ostream &OS,
   if (AS == 0 && !ForcePrint)
     return;
   OS << Prefix << "addrspace(";
-  StringRef ASName = M ? M->getDataLayout().getAddressSpaceName(AS) : "";
+  StringRef ASName = PrintSymbolicAddressSpace && M
+                         ? M->getDataLayout().getAddressSpaceName(AS)
+                         : "";
   if (!ASName.empty())
     OS << "\"" << ASName << "\"";
   else

llvm/test/Assembler/symbolic-addrspace-datalayout.ll

@@ -1,8 +1,9 @@
 ;; Check support for printing and parsing of address space names specified in
 ;; the datalayout.
 ; RUN: split-file %s %t --leading-lines
-; RUN: llvm-as < %t/num-to-sym.ll | llvm-dis | FileCheck %t/num-to-sym.ll
-; RUN: llvm-as < %t/sym-to-sym.ll | llvm-dis | FileCheck %t/sym-to-sym.ll
+; RUN: llvm-as < %t/num-to-sym.ll | llvm-dis --print-sym-addr-space=true  | FileCheck %t/num-to-sym.ll
+; RUN: llvm-as < %t/sym-to-sym.ll | llvm-dis --print-sym-addr-space=true  | FileCheck %t/sym-to-sym.ll
+; RUN: llvm-as < %t/sym-to-num.ll | llvm-dis --print-sym-addr-space=false | FileCheck %t/sym-to-num.ll
 ; RUN: not llvm-as < %t/invalid-name.ll 2>&1 | FileCheck %t/invalid-name.ll
 
 ;--- num-to-sym.ll
@@ -45,6 +46,26 @@ define void @bar() addrspace(11) {
   ret void
 }
 
+;--- sym-to-num.ll
+target datalayout = "P11-p2(global):32:8-p8(stack):8:8-p11(code):8:8"
+; CHECK: target datalayout = "P11-p2(global):32:8-p8(stack):8:8-p11(code):8:8"
+
+; CHECK: @str = private addrspace(2) constant [4 x i8] c"str\00"
+@str = private addrspace("global") constant [4 x i8] c"str\00"
+
+define void @foo() {
+  ; CHECK: %alloca = alloca i32, align 4, addrspace(8)
+  %alloca = alloca i32, addrspace("stack")
+  ret void
+}
+
+; CHECK: define void @bar() addrspace(11)
+define void @bar() addrspace(11) {
+  ; CHECK: call addrspace(11) void @foo()
+  call addrspace("code") void @foo()
+  ret void
+}
+
 ;--- invalid-name.ll
 target datalayout = "P11-p2(global):32:8-p8(stack):8:8-p11(code):8:8"
 ; CHECK: error: invalid symbolic addrspace 'global3'