From e7f5533a5a656cfd144d85a1b766522e432e33b3 Mon Sep 17 00:00:00 2001
From: Yaowen Mei <ywmei@google.com>
Date: Thu, 24 Oct 2024 03:41:33 +0000
Subject: [PATCH] Patch LLVM/Clang to support memtag-stack

Previously, we pypassed the clang flag `-fsanitize=memtag-stack` so that `m libc` was able to build with these two CLs (aosp/3261733, aosp/3264014).

But just found out today that this is not enough:

 1. `m libbase` was still falling back due to clang flag like this:
 `-fsanitize=integer,integer,memtag-stack`

 2. There are also some other targets depending on this flag (see
 example: https://paste.googleplex.com/4516018109284352)

This CL patched this github CL (http://shortn/_QQURhHpCQy) into reclient's input processor, so that re-client officially supports
this memtag-stack clang flag.

Test: abtd run: 1) caiman_fullmte_userdebug 8 fallbacks (http://shortn/_yy6YSVV0Cf), 2) kiyomi_fullmte-userdebug 8 fallbacks (http://shortn/_5UJCZ6PSjS)
Bug: b/371029823
Change-Id: I71651b00c27c0595a73ec1eb182277c55eaf929b
GitOrigin-RevId: 4f4b37ac14617145401b77709dda9738ab10aaf1
---
 .../action/cppcompile/preprocessor.go         |  3 ---
 .../action/cppcompile/preprocessor_test.go    |  1 -
 module_extensions/llvm.bzl                    |  4 +++-
 .../llvm-delay-sanitizer-args-parsing.patch   | 24 +++++++++++++++++++
 4 files changed, 27 insertions(+), 5 deletions(-)
 create mode 100644 third_party/patches/llvm/llvm-delay-sanitizer-args-parsing.patch

diff --git a/internal/pkg/inputprocessor/action/cppcompile/preprocessor.go b/internal/pkg/inputprocessor/action/cppcompile/preprocessor.go
index 2df77991..81fcf62e 100644
--- a/internal/pkg/inputprocessor/action/cppcompile/preprocessor.go
+++ b/internal/pkg/inputprocessor/action/cppcompile/preprocessor.go
@@ -258,9 +258,6 @@ func (p *Preprocessor) BuildCommandLine(outputFlag string, outputFlagJoined bool
 	args := []string{executablePath}
 	for _, flag := range p.Flags.Flags {
 		key, value := flag.Key, flag.Value
-		if key == "-fsanitize=" && value == "memtag-stack" {
-			continue
-		}
 		if key == clangCompilerArgFlag {
 			if _, present := toRemoveXclangFlags[value]; present {
 				continue
diff --git a/internal/pkg/inputprocessor/action/cppcompile/preprocessor_test.go b/internal/pkg/inputprocessor/action/cppcompile/preprocessor_test.go
index 2819dac6..63a06b13 100644
--- a/internal/pkg/inputprocessor/action/cppcompile/preprocessor_test.go
+++ b/internal/pkg/inputprocessor/action/cppcompile/preprocessor_test.go
@@ -343,7 +343,6 @@ func TestComputeSpec_SysrootAndProfileSampleUseArgsConvertedToAbsolutePath(t *te
 			{Key: "-isysroot", Value: "../c/d", Joined: true},
 			{Key: "--sysroot=", Value: fmt.Sprintf("%s/e/f", pwd), Joined: true},
 			{Key: "-fprofile-sample-use=", Value: "../c/d/abc.prof", Joined: true},
-			{Key: "-fsanitize=", Value: "memtag-stack", Joined: true},
 			{Key: "-fsanitize-blacklist=", Value: fmt.Sprintf("%s/e/f/ignores.txt", pwd), Joined: true},
 			{Key: "-fsanitize-ignorelist=", Value: fmt.Sprintf("%s/e/f/ignores2.txt", pwd), Joined: true},
 			{Key: "-fprofile-list=", Value: fmt.Sprintf("%s/e/f/fun.list", pwd), Joined: true},
diff --git a/module_extensions/llvm.bzl b/module_extensions/llvm.bzl
index 7cf38685..d32ea38e 100644
--- a/module_extensions/llvm.bzl
+++ b/module_extensions/llvm.bzl
@@ -1,4 +1,5 @@
 """Apply llvm_configure to produce a llvm-project repo."""
+
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 # Refer to go/rbe/dev/x/playbook/upgrading_clang_scan_deps
@@ -34,6 +35,7 @@ def _llvm_extension_impl(ctx):
             # @llvm//utils/bazel:configure.bzl, @llvm-raw is not pre-defined.
             "//third_party/patches/llvm:llvm-bzl-config.patch",
             "//third_party/patches/llvm:llvm-project-overlay-exectools.patch",
+            "//third_party/patches/llvm:llvm-delay-sanitizer-args-parsing.patch",
         ],
         sha256 = LLVM_SHA256,
         strip_prefix = "llvm-project-%s" % LLVM_COMMIT,
@@ -46,4 +48,4 @@ def _llvm_extension_impl(ctx):
 
 llvm_extension = module_extension(
     implementation = _llvm_extension_impl,
-)
\ No newline at end of file
+)
diff --git a/third_party/patches/llvm/llvm-delay-sanitizer-args-parsing.patch b/third_party/patches/llvm/llvm-delay-sanitizer-args-parsing.patch
new file mode 100644
index 00000000..be4aece1
--- /dev/null
+++ b/third_party/patches/llvm/llvm-delay-sanitizer-args-parsing.patch
@@ -0,0 +1,24 @@
+diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
+index ca992528ac2e..96695ef5b562 100644
+--- a/clang/lib/Driver/ToolChains/Clang.cpp
++++ b/clang/lib/Driver/ToolChains/Clang.cpp
+@@ -6351,8 +6351,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
+                    options::OPT_no_offload_new_driver, false))
+     CmdArgs.push_back("--offload-new-driver");
+ 
+-  SanitizeArgs.addArgs(TC, Args, CmdArgs, InputType);
+-
+   const XRayArgs &XRay = TC.getXRayArgs();
+   XRay.addArgs(TC, Args, CmdArgs, InputType);
+ 
+@@ -7176,6 +7174,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
+     }
+   }
+ 
++  // This needs to run after -Xclang argument forwarding to pick up the target
++  // features enabled through -Xclang -target-feature flags.
++  SanitizeArgs.addArgs(TC, Args, CmdArgs, InputType);
++
+   // With -save-temps, we want to save the unoptimized bitcode output from the
+   // CompileJobAction, use -disable-llvm-passes to get pristine IR generated
+   // by the frontend.