Reland "[lldb] Use shutil.which in Shell tests find_executable"

This reverts commit d9247cc.

With the Windows tests updated to expect .EXE suffixes. This changed
because shutil.which uses PATHEXT which will contain, amongst others,
"EXE".

Also I noticed the "." in ".exe" was the wildcard dot not literal
dot so I've escaped those.

Author: DavidSpickett

lldb/test/Shell/BuildScript/toolchain-clang-cl.test

@@ -23,9 +23,9 @@ CHECK-32: Cleaning {{.*}}toolchain-clang-cl.test.tmp{{.}}foo.exe-foobar.obj
 CHECK-32: Cleaning {{.*}}toolchain-clang-cl.test.tmp{{.}}foo.pdb
 CHECK-32: Cleaning {{.*}}toolchain-clang-cl.test.tmp{{.}}foo.exe
 CHECK-32: compiling foobar.c -> foo.exe-foobar.obj
-CHECK-32: {{.*}}clang-cl{{(.exe)?}} -m32
+CHECK-32: {{.*}}clang-cl{{(\.EXE)?}} -m32
 CHECK-32: linking foo.exe-foobar.obj -> foo.exe
-CHECK-32: {{.*}}lld-link
+CHECK-32: {{.*}}lld-link{{(\.EXE)?}}
 
 CHECK-64: Script Arguments:
 CHECK-64:   Arch: 64
@@ -44,6 +44,6 @@ CHECK-64: Cleaning {{.*}}toolchain-clang-cl.test.tmp{{.}}foo.exe-foobar.obj
 CHECK-64: Cleaning {{.*}}toolchain-clang-cl.test.tmp{{.}}foo.pdb
 CHECK-64: Cleaning {{.*}}toolchain-clang-cl.test.tmp{{.}}foo.exe
 CHECK-64: compiling foobar.c -> foo.exe-foobar.obj
-CHECK-64: {{.*}}clang-cl{{(.exe)?}} -m64
+CHECK-64: {{.*}}clang-cl{{(\.EXE)?}} -m64
 CHECK-64: linking foo.exe-foobar.obj -> foo.exe
-CHECK-64: {{.*}}lld-link{{(.exe)?}}
+CHECK-64: {{.*}}lld-link{{(\.EXE)?}}

lldb/test/Shell/BuildScript/toolchain-clang.test

@@ -7,8 +7,8 @@ RUN:    | FileCheck --check-prefix=CHECK --check-prefix=CHECK-64 %s
 CHECK: Cleaning {{.*}}toolchain-clang.test.tmp{{.}}foo.exe-foobar.o
 CHECK: Cleaning {{.*}}toolchain-clang.test.tmp{{.}}foo.exe
 CHECK: compiling foobar.c -> foo.exe-foobar.o
-CHECK-32: {{.*}}clang++{{(.exe)?}} -m32 -g -O0 -c -o {{.*}}foo.exe-foobar.o {{.*}}foobar.c
-CHECK-64: {{.*}}clang++{{(.exe)?}} -m64 -g -O0 -c -o {{.*}}foo.exe-foobar.o {{.*}}foobar.c
+CHECK-32: {{.*}}clang++{{(\.EXE)?}} -m32 -g -O0 -c -o {{.*}}foo.exe-foobar.o {{.*}}foobar.c
+CHECK-64: {{.*}}clang++{{(\.EXE)?}} -m64 -g -O0 -c -o {{.*}}foo.exe-foobar.o {{.*}}foobar.c
 CHECK: linking foo.exe-foobar.o -> foo.exe
-CHECK-32: {{.*}}clang++{{(.exe)?}} -m32 {{(-L.* )?(-Wl,-rpath,.* )?}}-o {{.*}}foo.exe {{.*}}foo.exe-foobar.o
-CHECK-64: {{.*}}clang++{{(.exe)?}} -m64 {{(-L.* )?(-Wl,-rpath,.* )?}}-o {{.*}}foo.exe {{.*}}foo.exe-foobar.o
+CHECK-32: {{.*}}clang++{{(\.EXE)?}} -m32 {{(-L.* )?(-Wl,-rpath,.* )?}}-o {{.*}}foo.exe {{.*}}foo.exe-foobar.o
+CHECK-64: {{.*}}clang++{{(\.EXE)?}} -m64 {{(-L.* )?(-Wl,-rpath,.* )?}}-o {{.*}}foo.exe {{.*}}foo.exe-foobar.o

lldb/test/Shell/BuildScript/toolchain-msvc.test

@@ -23,9 +23,9 @@ RUN:    | FileCheck --check-prefix=64BIT %s
 32BIT: Cleaning {{.*}}toolchain-msvc.test.tmp\foo.pdb
 32BIT: Cleaning {{.*}}toolchain-msvc.test.tmp\foo.exe
 32BIT: compiling foobar.c -> foo.exe-foobar.obj
-32BIT:   Command Line: {{.*}}\{{[Hh]ost[Xx](64|86)}}\{{(x86|arm)}}\cl.exe
+32BIT:   Command Line: {{.*}}\{{[Hh]ost[Xx](64|86)}}\{{(x86|arm)}}\cl.EXE
 32BIT: linking foo.exe-foobar.obj -> foo.exe
-32BIT:   Command Line: {{.*}}\{{[Hh]ost[Xx](64|86)}}\{{(x86|arm)}}\link.exe
+32BIT:   Command Line: {{.*}}\{{[Hh]ost[Xx](64|86)}}\{{(x86|arm)}}\link.EXE
 32BIT:   Env
 32BIT:     LIB = {{.*}}\ATLMFC\lib\{{(x86|arm)}}
 32BIT:           {{.*}}\lib\{{(x86|arm)}}
@@ -51,9 +51,9 @@ RUN:    | FileCheck --check-prefix=64BIT %s
 64BIT: Cleaning {{.*}}toolchain-msvc.test.tmp\foo.pdb
 64BIT: Cleaning {{.*}}toolchain-msvc.test.tmp\foo.exe
 64BIT: compiling foobar.c -> foo.exe-foobar.obj
-64BIT:   Command Line: {{.*}}\{{[Hh]ost[Xx](64|86)}}\{{(x64|arm64)}}\cl.exe
+64BIT:   Command Line: {{.*}}\{{[Hh]ost[Xx](64|86)}}\{{(x64|arm64)}}\cl.EXE
 64BIT: linking foo.exe-foobar.obj -> foo.exe
-64BIT:   Command Line: {{.*}}\{{[Hh]ost[Xx](64|86)}}\{{(x64|arm64)}}\link.exe
+64BIT:   Command Line: {{.*}}\{{[Hh]ost[Xx](64|86)}}\{{(x64|arm64)}}\link.EXE
 64BIT:   Env
 64BIT:     LIB = {{.*}}\ATLMFC\lib\{{(x64|arm64)}}
 64BIT:           {{.*}}\lib\{{(x64|arm64)}}

lldb/test/Shell/helper/build.py

@@ -4,6 +4,7 @@
 
 import argparse
 import os
+import shutil
 import signal
 import subprocess
 import sys
@@ -170,16 +171,14 @@ def print_environment(env):
         print('    {0} = {1}'.format(e, formatted_value))
 
 def find_executable(binary_name, search_paths):
-    if sys.platform == 'win32':
-        binary_name = binary_name + '.exe'
-
-    search_paths = os.pathsep.join(search_paths)
-    paths = search_paths + os.pathsep + os.environ.get('PATH', '')
-    for path in paths.split(os.pathsep):
-        p = os.path.join(path, binary_name)
-        if os.path.exists(p) and not os.path.isdir(p):
-            return os.path.normpath(p)
-    return None
+    # shutil.which will ignore PATH if given a path argument, we want to include it.
+    search_paths.append(os.environ.get('PATH', ''))
+    search_path = os.pathsep.join(search_paths)
+    binary_path = shutil.which(binary_name, path=search_path)
+    if binary_path is not None:
+        # So for example, we get '/bin/gcc' instead of '/usr/../bin/gcc'.
+        binary_path = os.path.normpath(binary_path)
+    return binary_path
 
 def find_toolchain(compiler, tools_dir):
     if compiler == 'msvc':