From 10ea7316995dca0c9e31da5f838053885680f5f3 Mon Sep 17 00:00:00 2001
From: Jonas Devlieghere <jonas@devlieghere.com>
Date: Wed, 19 Jan 2022 21:50:51 -0800
Subject: [PATCH] [dsymutil] Don't print timestamp warning if we have no
 timestamp

If we have no timestamp (0), don't print the corresponding warning. The
binary holder already successfully ignores these cases, but the warning
for swift interface files was lacking it.

rdar://86036385

Differential revision: https://reviews.llvm.org/D117333
---
 llvm/test/tools/dsymutil/X86/swift-ast-x86_64.test | 5 ++---
 llvm/tools/dsymutil/DwarfLinkerForBinary.cpp       | 3 ++-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/llvm/test/tools/dsymutil/X86/swift-ast-x86_64.test b/llvm/test/tools/dsymutil/X86/swift-ast-x86_64.test
index 43d930af7128..a16330d8c1b0 100644
--- a/llvm/test/tools/dsymutil/X86/swift-ast-x86_64.test
+++ b/llvm/test/tools/dsymutil/X86/swift-ast-x86_64.test
@@ -1,4 +1,5 @@
 RUN: dsymutil -oso-prepend-path %p/.. %p/../Inputs/swift-ast.macho.x86_64 -o %T/swift-ast.dSYM -verbose -no-swiftmodule-timestamp | FileCheck %s --check-prefix=DSYMUTIL
+RUN: dsymutil -oso-prepend-path %p/.. %p/../Inputs/swift-ast.macho.x86_64 -o %T/swift-ast.dSYM -verbose | FileCheck %s --check-prefix=DSYMUTIL
 RUN: llvm-readobj --sections --section-data %T/swift-ast.dSYM/Contents/Resources/DWARF/swift-ast.macho.x86_64 | FileCheck %s --check-prefix=READOBJ
 RUN: llvm-dwarfdump --show-section-sizes %T/swift-ast.dSYM/Contents/Resources/DWARF/swift-ast.macho.x86_64 | FileCheck %s --check-prefix=DWARFDUMP
 
@@ -11,6 +12,7 @@ Compiled with:
 
 DSYMUTIL: filename:{{.*}}swift-ast.swiftmodule
 DSYMUTIL-NOT: The file was not recognized as a valid object file
+DSYMUTIL-NOT: timestamp mismatch
 DSYMUTIL: DEBUG MAP OBJECT:{{.*}}swift-ast.swiftmodule
 
 READOBJ: Name:{{.*}}__swift_ast
@@ -19,8 +21,5 @@ READOBJ-NEXT: |.|
 
 DWARFDUMP: __swift_ast
 
-RUN: dsymutil -oso-prepend-path %p/.. %p/../Inputs/swift-ast.macho.x86_64 -no-output -verbose 2>&1 | FileCheck %s --check-prefix=TIMESTAMP
-TIMESTAMP: warning: {{.*}}/swift-ast.swiftmodule: timestamp mismatch between swift interface file ({{.*}}) and debug map ({{.*}})
-
 RUN: dsymutil -s %T/swift-ast.dSYM/Contents/Resources/DWARF/swift-ast.macho.x86_64 | FileCheck %s --check-prefix=NAST
 NAST-NOT: N_AST
diff --git a/llvm/tools/dsymutil/DwarfLinkerForBinary.cpp b/llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
index 809b5f799b06..a8dfde086537 100644
--- a/llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
+++ b/llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
@@ -414,7 +414,8 @@ bool DwarfLinkerForBinary::link(const DebugMap &Map) {
         auto ModificationTime =
             std::chrono::time_point_cast<std::chrono::seconds>(
                 Stat.getLastModificationTime());
-        if (ModificationTime != Obj->getTimestamp()) {
+        if (Obj->getTimestamp() != sys::TimePoint<>() &&
+            ModificationTime != Obj->getTimestamp()) {
           // Not using the helper here as we can easily stream TimePoint<>.
           WithColor::warning()
               << File << ": timestamp mismatch between swift interface file ("