[clang] 7bd492f - [clang dependency scanning] Make Current Working Directory Optimization Off by Default (#129809)

[via cfe-commits]

Author: Qiongsi Wu
Date: 2025-03-05T09:03:04-08:00
New Revision: 7bd492ffe84b549bc0f3b26e3aab973fa81069a5

URL: https://github.com/llvm/llvm-project/commit/7bd492ffe84b549bc0f3b26e3aab973fa81069a5
DIFF: https://github.com/llvm/llvm-project/commit/7bd492ffe84b549bc0f3b26e3aab973fa81069a5.diff

LOG: [clang dependency scanning] Make Current Working Directory Optimization Off by Default (#129809)

https://github.com/llvm/llvm-project/pull/124786 implemented current
working directory (CWD) optimization and the optimization was on by
default. We have discovered that build system needs to be compatible
with the CWD optimization and default off is a better behavior. The
build system needs to be aware that the current working directory is
ignored. Without a good way of notifying the build system, it is less
risky to default to off. This PR implement the change.

rdar://145860213

Added: 
    

Modified: 
    clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h
    clang/test/ClangScanDeps/modules-context-hash-cwd.c
    clang/test/ClangScanDeps/modules-debug-dir.c

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h b/clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h
index f002f8645d3f6..816e122eb3003 100644
--- a/clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h
+++ b/clang/include/clang/Tooling/DependencyScanning/DependencyScanningService.h
@@ -67,7 +67,11 @@ enum class ScanningOptimizations {
   IgnoreCWD = (1 << 4),
 
   DSS_LAST_BITMASK_ENUM(IgnoreCWD),
-  Default = All
+
+  // The build system needs to be aware that the current working
+  // directory is ignored. Without a good way of notifying the build
+  // system, it is less risky to default to off.
+  Default = All & (~IgnoreCWD)
 };
 
 #undef DSS_LAST_BITMASK_ENUM

diff  --git a/clang/test/ClangScanDeps/modules-context-hash-cwd.c b/clang/test/ClangScanDeps/modules-context-hash-cwd.c
index 459d2c90debe6..c609a7dcbc80e 100644
--- a/clang/test/ClangScanDeps/modules-context-hash-cwd.c
+++ b/clang/test/ClangScanDeps/modules-context-hash-cwd.c
@@ -9,14 +9,14 @@
 // RUN: sed -e "s|DIR|%/t|g" %t/cdb3.json.in > %t/cdb3.json
 // RUN: sed -e "s|DIR|%/t|g" %t/cdb4.json.in > %t/cdb4.json
 // RUN: sed -e "s|DIR|%/t|g" %t/cdb5.json.in > %t/cdb5.json
-// RUN: clang-scan-deps -compilation-database %t/cdb0.json -format experimental-full > %t/result0.json
-// RUN: clang-scan-deps -compilation-database %t/cdb1.json -format experimental-full > %t/result1.json
+// RUN: clang-scan-deps -compilation-database %t/cdb0.json -format experimental-full -optimize-args=all > %t/result0.json
+// RUN: clang-scan-deps -compilation-database %t/cdb1.json -format experimental-full -optimize-args=all > %t/result1.json
 // It is not a typo to use cdb1.json for result2. We intend to use the same
 // compilation database, but 
diff erent clang-scan-deps optimize-args options.
 // RUN: clang-scan-deps -compilation-database %t/cdb1.json -format experimental-full -optimize-args=header-search,system-warnings,vfs,canonicalize-macros > %t/result2.json
-// RUN: clang-scan-deps -compilation-database %t/cdb3.json -format experimental-full > %t/result3.json
-// RUN: clang-scan-deps -compilation-database %t/cdb4.json -format experimental-full > %t/result4.json
-// RUN: clang-scan-deps -compilation-database %t/cdb5.json -format experimental-full > %t/result5.json
+// RUN: clang-scan-deps -compilation-database %t/cdb3.json -format experimental-full -optimize-args=all > %t/result3.json
+// RUN: clang-scan-deps -compilation-database %t/cdb4.json -format experimental-full -optimize-args=all > %t/result4.json
+// RUN: clang-scan-deps -compilation-database %t/cdb5.json -format experimental-full -optimize-args=all > %t/result5.json
 // RUN: cat %t/result0.json %t/result1.json | FileCheck %s
 // RUN: cat %t/result0.json %t/result2.json | FileCheck %s -check-prefix=SKIPOPT
 // RUN: cat %t/result3.json %t/result4.json | FileCheck %s -check-prefix=RELPATH

diff  --git a/clang/test/ClangScanDeps/modules-debug-dir.c b/clang/test/ClangScanDeps/modules-debug-dir.c
index fadec1ad52e35..c4fb4982ed791 100644
--- a/clang/test/ClangScanDeps/modules-debug-dir.c
+++ b/clang/test/ClangScanDeps/modules-debug-dir.c
@@ -4,7 +4,7 @@
 // RUN: split-file %s %t
 // RUN: sed -e "s|DIR|%/t|g" %t/cdb.json.in > %t/cdb.json
 // RUN: clang-scan-deps -compilation-database %t/cdb.json -format \
-// RUN:   experimental-full > %t/result.json
+// RUN:   experimental-full -optimize-args=all > %t/result.json
 // RUN: cat %t/result.json | sed 's:\\\\\?:/:g' | FileCheck %s
 
 //--- cdb.json.in