[lit] Fix internal diff's --strip-trailing-cr and use it

Using GNU diff, `--strip-trailing-cr` removes a `\r` appearing before
a `\n` at the end of a line.  Without this patch, lit's internal diff
only removes `\r` if it appears as the last character.  That seems
useless.  This patch fixes that.

This patch also adds `--strip-trailing-cr` to some tests that fail on
Windows bots when D68664 is applied.  Based on what I see in the bot
logs, I think the following is happening.  In each test there, lit
diff is comparing a file with `\r\n` line endings to a file with `\n`
line endings.  Without D68664, lit diff reads those files with
Python's universal newlines support activated, causing `\r` to be
dropped.  However, with D68664, lit diff reads the files in binary
mode instead and thus reports that every line is different, just as
GNU diff does (at least under Ubuntu).  Adding `--strip-trailing-cr`
to those tests restores the previous behavior while permitting the
behavior of lit diff to be more like GNU diff.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D68839

llvm-svn: 374652

5 files changed, 72 insertions, 3 deletions

diff --git a/llvm/utils/lit/tests/Inputs/shtest-shell/diff-in.dos b/llvm/utils/lit/tests/Inputs/shtest-shell/diff-in.dos
new file mode 100644
index 00000000000..7a0560654c5
--- /dev/null
+++ b/llvm/utils/lit/tests/Inputs/shtest-shell/diff-in.dos
@@ -0,0 +1,3 @@
+In this file, the

+sequence "\r\n"

+terminates lines.

diff --git a/llvm/utils/lit/tests/Inputs/shtest-shell/diff-in.unix b/llvm/utils/lit/tests/Inputs/shtest-shell/diff-in.unix
new file mode 100644
index 00000000000..58208a3ae76
--- /dev/null
+++ b/llvm/utils/lit/tests/Inputs/shtest-shell/diff-in.unix
@@ -0,0 +1,3 @@
+In this file, the
+sequence "\n"
+terminates lines.
diff --git a/llvm/utils/lit/tests/Inputs/shtest-shell/diff-strip-trailing-cr.txt b/llvm/utils/lit/tests/Inputs/shtest-shell/diff-strip-trailing-cr.txt
new file mode 100644
index 00000000000..6111a8fbf72
--- /dev/null
+++ b/llvm/utils/lit/tests/Inputs/shtest-shell/diff-strip-trailing-cr.txt
@@ -0,0 +1,10 @@
+# Check behavior of --strip-trailing-cr.
+
+# RUN: diff -u diff-in.dos diff-in.unix && false || true
+# RUN: diff -u diff-in.unix diff-in.dos && false || true
+
+# RUN: diff -u --strip-trailing-cr diff-in.dos diff-in.unix && false || true
+# RUN: diff -u --strip-trailing-cr diff-in.unix diff-in.dos && false || true
+
+# Fail so lit will print output.
+# RUN: false
diff --git a/llvm/utils/lit/tests/max-failures.py b/llvm/utils/lit/tests/max-failures.py
index 3b85ae18611..6ad37533692 100644
--- a/llvm/utils/lit/tests/max-failures.py
+++ b/llvm/utils/lit/tests/max-failures.py
@@ -8,7 +8,7 @@
 #
 # END.
 
-# CHECK: Failing Tests (31)
+# CHECK: Failing Tests (32)
 # CHECK: Failing Tests (1)
 # CHECK: Failing Tests (2)
 # CHECK: error: argument --max-failures: requires positive integer, but found '0'
diff --git a/llvm/utils/lit/tests/shtest-shell.py b/llvm/utils/lit/tests/shtest-shell.py
index c7e05d6bc42..adbe4dc56a1 100644
--- a/llvm/utils/lit/tests/shtest-shell.py
+++ b/llvm/utils/lit/tests/shtest-shell.py
@@ -4,7 +4,7 @@
 # FIXME: Temporarily dump test output so we can debug failing tests on
 # buildbots.
 # RUN: cat %t.out
-# RUN: FileCheck --input-file %t.out %s
+# RUN: FileCheck --dump-input=fail --color -vv --input-file %t.out %s
 #
 # END.
 
@@ -332,6 +332,59 @@
 # CHECK: PASS: shtest-shell :: diff-r.txt
 
 
+# CHECK: FAIL: shtest-shell :: diff-strip-trailing-cr.txt
+
+# CHECK: *** TEST 'shtest-shell :: diff-strip-trailing-cr.txt' FAILED ***
+
+# CHECK: $ "diff" "-u" "diff-in.dos" "diff-in.unix"
+# CHECK: # command output:
+# CHECK: @@
+# CHECK-NEXT: -In this file, the
+# CHECK-NEXT: -sequence "\r\n"
+# CHECK-NEXT: -terminates lines.
+# CHECK-NEXT: +In this file, the
+# CHECK-NEXT: +sequence "\n"
+# CHECK-NEXT: +terminates lines.
+# CHECK: error: command failed with exit status: 1
+# CHECK: $ "true"
+
+# CHECK: $ "diff" "-u" "diff-in.unix" "diff-in.dos"
+# CHECK: # command output:
+# CHECK: @@
+# CHECK-NEXT: -In this file, the
+# CHECK-NEXT: -sequence "\n"
+# CHECK-NEXT: -terminates lines.
+# CHECK-NEXT: +In this file, the
+# CHECK-NEXT: +sequence "\r\n"
+# CHECK-NEXT: +terminates lines.
+# CHECK: error: command failed with exit status: 1
+# CHECK: $ "true"
+
+# CHECK: $ "diff" "-u" "--strip-trailing-cr" "diff-in.dos" "diff-in.unix"
+# CHECK: # command output:
+# CHECK: @@
+# CHECK-NEXT:  In this file, the
+# CHECK-NEXT: -sequence "\r\n"
+# CHECK-NEXT: +sequence "\n"
+# CHECK-NEXT:  terminates lines.
+# CHECK: error: command failed with exit status: 1
+# CHECK: $ "true"
+
+# CHECK: $ "diff" "-u" "--strip-trailing-cr" "diff-in.unix" "diff-in.dos"
+# CHECK: # command output:
+# CHECK: @@
+# CHECK-NEXT:  In this file, the
+# CHECK-NEXT: -sequence "\n"
+# CHECK-NEXT: +sequence "\r\n"
+# CHECK-NEXT:  terminates lines.
+# CHECK: error: command failed with exit status: 1
+# CHECK: $ "true"
+
+# CHECK: $ "false"
+
+# CHECK: ***
+
+
 # CHECK: FAIL: shtest-shell :: diff-unified.txt
 
 # CHECK: *** TEST 'shtest-shell :: diff-unified.txt' FAILED ***
@@ -486,4 +539,4 @@
 # CHECK: PASS: shtest-shell :: sequencing-0.txt
 # CHECK: XFAIL: shtest-shell :: sequencing-1.txt
 # CHECK: PASS: shtest-shell :: valid-shell.txt
-# CHECK: Failing Tests (31)
+# CHECK: Failing Tests (32)