Don't modify archive members unless really needed.

For whatever reason ld64 requires that member headers (not the member
themselves) should be aligned. The only way to do that is to edit the
previous member so that it ends at an aligned boundary.

Since modifying data put in an archive is an undesirable property,
llvm-ar should only do it when it is absolutely necessary.

llvm-svn: 295765

3 files changed, 37 insertions, 7 deletions

diff --git a/llvm/test/Object/archive-extract.test b/llvm/test/Object/archive-extract.test
index a3c69e50151..b8ed65a3053 100644
--- a/llvm/test/Object/archive-extract.test
+++ b/llvm/test/Object/archive-extract.test
@@ -43,10 +43,10 @@
 CHECK-GNU: 1465 2004-11-19 03:01:31.000000000 very_long_bytecode_file_name.bc
 
 ; RUN: rm -f %t.a
-; RUN: llvm-ar -format bsd rcU %t.a very_long_bytecode_file_name.bc
-; RUN: env TZ=GMT llvm-ar tv %t.a | FileCheck %s -check-prefix CHECK-BSD
+; RUN: llvm-ar -format darwin rcU %t.a very_long_bytecode_file_name.bc
+; RUN: env TZ=GMT llvm-ar tv %t.a | FileCheck %s -check-prefix CHECK-DARWIN
 
-CHECK-BSD: 1472 2004-11-19 03:01:31.000000000 very_long_bytecode_file_name.bc
+CHECK-DARWIN: 1472 2004-11-19 03:01:31.000000000 very_long_bytecode_file_name.bc
 
 RUN: not llvm-ar x %p/Inputs/GNU.a foo.o 2>&1 | FileCheck --check-prefix=NOTFOUND %s
 NOTFOUND: foo.o was not found
diff --git a/llvm/test/Object/archive-format.test b/llvm/test/Object/archive-format.test
index 7505b1ffd5b..f895a36bce3 100644
--- a/llvm/test/Object/archive-format.test
+++ b/llvm/test/Object/archive-format.test
@@ -32,12 +32,23 @@ RUN: llvm-ar --format=bsd rc %t.a 0123456789abcde 0123456789abcdef
 RUN: cat %t.a | FileCheck -strict-whitespace --check-prefix=BSD %s
 
 BSD:      !<arch>
-BSD-NEXT: #1/20           0           0     0     644     28        `
+BSD-NEXT: #1/20           0           0     0     644     24        `
+BSD-NEXT: 0123456789abcde{{.....}}bar.
+BSD-SAME: #1/16           0           0     0     644     20        `
+BSD-NEXT: 0123456789abcdefzed.
+
+RUN: rm -f %t.a
+RUN: llvm-ar --format=darwin rc %t.a 0123456789abcde 0123456789abcdef
+RUN: cat %t.a | FileCheck -strict-whitespace --check-prefix=DARWIN %s
+
+DARWIN:      !<arch>
+DARWIN-NEXT: #1/20           0           0     0     644     28        `
 Each [[:space:]] matches a newline.  We explicitly match 3 newlines, as the
 fourth newline is implicitly consumed by FileCheck and cannot be matched.
-BSD-NEXT: 0123456789abcde{{.....}}bar.{{[[:space:]][[:space:]][[:space:]]}}
-BSD-NEXT: #1/20           0           0     0     644     28        `
-BSD-NEXT: 0123456789abcdef{{....}}zed.
+DARWIN-NEXT: 0123456789abcde{{.....}}bar.{{[[:space:]][[:space:]][[:space:]]}}
+DARWIN-NEXT: #1/20           0           0     0     644     28        `
+DARWIN-NEXT: 0123456789abcdef{{....}}zed.
+
 
 RUN: rm -f test.a
 RUN: llvm-ar --format=gnu rcT test.a 0123456789abcde 0123456789abcdef
diff --git a/llvm/test/Object/archive-pad.test b/llvm/test/Object/archive-pad.test
new file mode 100644
index 00000000000..e906791787a
--- /dev/null
+++ b/llvm/test/Object/archive-pad.test
@@ -0,0 +1,19 @@
+Test that only the darwin format needs to modify archive members to
+avoid a ld64 bug.
+
+RUN: echo foo > %t.o
+
+RUN: rm -f %t.a
+RUN: llvm-ar -format=bsd rc %t.a %t.o
+RUN: llvm-ar p %t.a > %bsd.o
+RUN: cmp %bsd.o %t.o
+
+RUN: rm -f %t.a
+RUN: llvm-ar -format=gnu rc %t.a %t.o
+RUN: llvm-ar p %t.a > %gnu.o
+RUN: cmp %gnu.o %t.o
+
+RUN: rm -f %t.a
+RUN: llvm-ar -format=darwin rc %t.a %t.o
+RUN: llvm-ar p %t.a > %darwin.o
+RUN: not cmp %darwin.o %t.o