[llvm] [llvm][Docs] Make it clear where lit test files live (PR #124121)

[David Spickett via llvm-commits]

https://github.com/DavidSpickett created https://github.com/llvm/llvm-project/pull/124121

As someone on Discord was understandably confused because the build directory does contain folder structures that look remarkably like the source directory.

I used this page to explain it but realised that this must be from when llvm was a separate repository. So <user home>/llvm probably was a common path.

Now it's in llvm-project. So make that obvious in the instructions.

>From f54e602988ecf51996e889f45290985ec0a15e65 Mon Sep 17 00:00:00 2001
From: David Spickett <david.spickett at linaro.org>
Date: Thu, 23 Jan 2025 14:29:55 +0000
Subject: [PATCH] [llvm][Docs] Make it clear where lit test files live

As someone on Discord was understandably confused because the
build directory does contain folder structures that look
remarkably like the source directory.

I used this page to explain it but realised that this must
be from when llvm was a separate repository. So <user home>/llvm
probably was a common path.

Now it's in llvm-project. So make that obvious in the instructions.
---
 llvm/docs/TestingGuide.rst | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/llvm/docs/TestingGuide.rst b/llvm/docs/TestingGuide.rst
index 08617933519fdb..b6dda6a7324056 100644
--- a/llvm/docs/TestingGuide.rst
+++ b/llvm/docs/TestingGuide.rst
@@ -167,13 +167,17 @@ script which is built as part of LLVM. For example, to run the
 
 .. code-block:: bash
 
-    % llvm-lit ~/llvm/test/Integer/BitPacked.ll
+    % llvm-lit <path to llvm-project>/llvm/test/Integer/BitPacked.ll
 
-or to run all of the ARM CodeGen tests:
+.. note::
+   The test files are in the ``llvm-project`` directory, not the directory you
+   are building LLVM in.
+
+Or you can run a whole folder of tests. To run all of the ARM CodeGen tests:
 
 .. code-block:: bash
 
-    % llvm-lit ~/llvm/test/CodeGen/ARM
+    % llvm-lit <path to llvm-project>/llvm/test/CodeGen/ARM
 
 The regression tests will use the Python psutil module only if installed in a
 **non-user** location. Under Linux, install with sudo or within a virtual