[lld] [LLD] [COFF] Pick timestamps from the SOURCE_DATE_EPOCH variable (PR #81326)

Martin Storsjö via llvm-commits llvm-commits at lists.llvm.org
Sat Feb 10 04:14:42 PST 2024


https://github.com/mstorsjo updated https://github.com/llvm/llvm-project/pull/81326

>From 1e8254e60bad8f8a2286daedd41dd36660e757f6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin at martin.st>
Date: Sat, 10 Feb 2024 00:36:16 +0200
Subject: [PATCH 1/2] [LLD] [COFF] Pick timestamps from the SOURCE_DATE_EPOCH
 variable

The SOURCE_DATE_EPOCH environment variable can be set in order
to get reproducible build.

When linking PE/COFF modules with LLD, the timestamp field is
set to the current time, unless either the /timestamp: or
/Brepro option is set. If neither of them is set, check the
SOURCE_DATE_EPOCH variable, before resorting to using the
actual current date and time.
---
 lld/COFF/Driver.cpp          | 10 +++++++++-
 lld/test/COFF/timestamp.test |  2 ++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index e0afb6b18805b2..22ee2f133be98a 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -1825,7 +1825,15 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
     }
   } else {
     config->repro = false;
-    config->timestamp = time(nullptr);
+    if (std::optional<std::string> epoch =
+            Process::GetEnv("SOURCE_DATE_EPOCH")) {
+      StringRef value(*epoch);
+      if (value.getAsInteger(0, config->timestamp))
+        fatal(Twine("invalid SOURCE_DATE_EPOCH timestamp: ") + value +
+              ".  Expected 32-bit integer");
+    } else {
+      config->timestamp = time(nullptr);
+    }
   }
 
   // Handle /alternatename
diff --git a/lld/test/COFF/timestamp.test b/lld/test/COFF/timestamp.test
index fbdc5788a33a55..f94eeee8793f01 100644
--- a/lld/test/COFF/timestamp.test
+++ b/lld/test/COFF/timestamp.test
@@ -3,9 +3,11 @@ RUN: yaml2obj %p/Inputs/generic.yaml -o %t.obj
 RUN: lld-link %t.obj /debug /Brepro /entry:main /nodefaultlib /out:%t.1.exe
 RUN: lld-link %t.obj /debug /Brepro /entry:main /nodefaultlib /out:%t.2.exe
 RUN: lld-link %t.obj /debug /timestamp:0 /entry:main /nodefaultlib /out:%t.3.exe
+RUN: env SOURCE_DATE_EPOCH=0 lld-link %t.obj /debug /entry:main /nodefaultlib /out:%t.4.exe
 RUN: llvm-readobj --file-headers --coff-debug-directory %t.1.exe | FileCheck %s --check-prefix=HASH
 RUN: llvm-readobj --file-headers --coff-debug-directory %t.2.exe | FileCheck %s --check-prefix=HASH
 RUN: llvm-readobj --file-headers --coff-debug-directory %t.3.exe | FileCheck %s --check-prefix=ZERO
+RUN: llvm-readobj --file-headers --coff-debug-directory %t.4.exe | FileCheck %s --check-prefix=ZERO
 
 HASH: ImageFileHeader {
 HASH: TimeDateStamp: [[STAMP:.*]]

>From a0bd398f9162a015103588cc15b17bb4d444bbbb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin at martin.st>
Date: Sat, 10 Feb 2024 14:14:07 +0200
Subject: [PATCH 2/2] Test more cases

---
 lld/test/COFF/timestamp.test | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/lld/test/COFF/timestamp.test b/lld/test/COFF/timestamp.test
index f94eeee8793f01..c0658d6109811b 100644
--- a/lld/test/COFF/timestamp.test
+++ b/lld/test/COFF/timestamp.test
@@ -4,10 +4,18 @@ RUN: lld-link %t.obj /debug /Brepro /entry:main /nodefaultlib /out:%t.1.exe
 RUN: lld-link %t.obj /debug /Brepro /entry:main /nodefaultlib /out:%t.2.exe
 RUN: lld-link %t.obj /debug /timestamp:0 /entry:main /nodefaultlib /out:%t.3.exe
 RUN: env SOURCE_DATE_EPOCH=0 lld-link %t.obj /debug /entry:main /nodefaultlib /out:%t.4.exe
+RUN: lld-link %t.obj /debug /timestamp:4294967295 /entry:main /nodefaultlib /out:%t.5.exe
+RUN: env SOURCE_DATE_EPOCH=4294967295 lld-link %t.obj /debug /entry:main /nodefaultlib /out:%t.6.exe
+RUN: env SOURCE_DATE_EPOCH=12345 lld-link %t.obj /debug /timestamp:0 /entry:main /nodefaultlib /out:%t.7.exe
+RUN: env LLD_IN_TEST=1 not lld-link %t.obj /debug /timestamp:4294967296 /entry:main /nodefaultlib /out:%t.8.exe 2>&1 | FileCheck %s --check-prefix=ERROR
+RUN: env SOURCE_DATE_EPOCH=4294967296 env LLD_IN_TEST=1 not lld-link %t.obj /debug /entry:main /nodefaultlib /out:%t.9.exe 2>&1 | FileCheck %s --check-prefix=ERROR2
 RUN: llvm-readobj --file-headers --coff-debug-directory %t.1.exe | FileCheck %s --check-prefix=HASH
 RUN: llvm-readobj --file-headers --coff-debug-directory %t.2.exe | FileCheck %s --check-prefix=HASH
 RUN: llvm-readobj --file-headers --coff-debug-directory %t.3.exe | FileCheck %s --check-prefix=ZERO
 RUN: llvm-readobj --file-headers --coff-debug-directory %t.4.exe | FileCheck %s --check-prefix=ZERO
+RUN: llvm-readobj --file-headers --coff-debug-directory %t.5.exe | FileCheck %s --check-prefix=MAX
+RUN: llvm-readobj --file-headers --coff-debug-directory %t.6.exe | FileCheck %s --check-prefix=MAX
+RUN: llvm-readobj --file-headers --coff-debug-directory %t.7.exe | FileCheck %s --check-prefix=ZERO
 
 HASH: ImageFileHeader {
 HASH: TimeDateStamp: [[STAMP:.*]]
@@ -18,3 +26,11 @@ ZERO: ImageFileHeader {
 ZERO: TimeDateStamp: 1970-01-01 00:00:00 (0x0)
 ZERO: DebugDirectory [
 ZERO: TimeDateStamp: 1970-01-01 00:00:00 (0x0)
+
+MAX: ImageFileHeader {
+MAX: TimeDateStamp: 2106-02-07 06:28:15 (0xFFFFFFFF)
+MAX: DebugDirectory [
+MAX: TimeDateStamp: 2106-02-07 06:28:15 (0xFFFFFFFF)
+
+ERROR: error: invalid timestamp: 4294967296.  Expected 32-bit integer
+ERROR2: error: invalid SOURCE_DATE_EPOCH timestamp: 4294967296.  Expected 32-bit integer



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