[DTLTO][PS4,PS5] Suppress system headers directory warning

[bd1976bris]

Our driver warns under various circumstances if SDK directories can't be found.

This warning is not applicable in ThinLTO codegen mode (-fthinlto-index=). Suppress it.

The motivation for doing this is that we sometimes see this warning emitted when DTLTO invokes the compiler on a remote machine to do the LTO backend compilations (with -fthinlto-index=).

Internal Ref: TOOLCHAIN-20592

[llvmbot]

@llvm/pr-subscribers-clang-driver

@llvm/pr-subscribers-clang

Author: Ben Dunbobbin (bd1976bris)

Changes

Our driver warns under various circumstances if SDK directories can't be found.

This warning is not applicable in ThinLTO codegen mode (-fthinlto-index=). Suppress it.

The motivation for doing this is that we sometimes see this warning emitted when DTLTO invokes the compiler on a remote machine to do the LTO backend compilations (with -fthinlto-index=).

Internal Ref: TOOLCHAIN-20592

---

Full diff: https://github.com/llvm/llvm-project/pull/167685.diff

3 Files Affected:

• (modified) clang/lib/Driver/ToolChains/PS4CPU.cpp (+3)
• (modified) clang/test/Driver/ps4-sdk-root.c (+8)
• (modified) clang/test/Driver/ps5-sdk-root.c (+8)

diff --git a/clang/lib/Driver/ToolChains/PS4CPU.cpp b/clang/lib/Driver/ToolChains/PS4CPU.cpp
index 6fe18aa4cceba..5b5b5607da69e 100644
--- a/clang/lib/Driver/ToolChains/PS4CPU.cpp
+++ b/clang/lib/Driver/ToolChains/PS4CPU.cpp
@@ -488,6 +488,9 @@ toolchains::PS4PS5Base::PS4PS5Base(const Driver &D, const llvm::Triple &Triple,
   // control of header or library search. If we're not linking, don't check
   // for missing libraries.
   auto CheckSDKPartExists = [&](StringRef Dir, StringRef Desc) {
+    // In ThinLTO code generation mode SDK files are not required.
+    if (Args.hasArgNoClaim(options::OPT_fthinlto_index_EQ))
+      return true;
     if (llvm::sys::fs::exists(Dir))
       return true;
     D.Diag(clang::diag::warn_drv_unable_to_find_directory_expected)
diff --git a/clang/test/Driver/ps4-sdk-root.c b/clang/test/Driver/ps4-sdk-root.c
index 6e5f1e28958ad..7c568a6680f25 100644
--- a/clang/test/Driver/ps4-sdk-root.c
+++ b/clang/test/Driver/ps4-sdk-root.c
@@ -11,6 +11,9 @@
 ///
 /// The default <SDKROOT> for both headers and libraries is taken from the
 /// SCE_ORBIS_SDK_DIR environment variable.
+///
+/// In ThinLTO code generation mode (-fthinlto-index=) SDK files are not required
+/// so all warnings are suppressed.
 
 // RUN: echo "-### -Winvalid-or-nonexistent-directory -target x86_64-scei-ps4" > %t.rsp
 
@@ -31,6 +34,11 @@
 /// headers and libraries.
 // RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s 2>&1 | FileCheck -check-prefixes=WARN-SYS-HEADERS,WARN-SYS-LIBS,NO-WARN %s
 
+/// -fthinlto-index= warning suppression.
+// RUN: %clang -O2 %s -flto=thin -c -o %t.o
+// RUN: llvm-lto -thinlto -o %t %t.o
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %t.o -fthinlto-index=%t.thinlto.bc 2>&1 | FileCheck -check-prefixes=NO-WARN %s
+
 /// If `-c`, `-S`, `-E` or `-emit-ast` is supplied, the existence check for SDK
 /// libraries is skipped because no linking will be performed. We only expect
 /// warnings about missing headers.
diff --git a/clang/test/Driver/ps5-sdk-root.c b/clang/test/Driver/ps5-sdk-root.c
index 16ef2cc01f5e7..558601d3a2082 100644
--- a/clang/test/Driver/ps5-sdk-root.c
+++ b/clang/test/Driver/ps5-sdk-root.c
@@ -13,6 +13,9 @@
 ///
 /// The default <SDKROOT> for both headers and libraries is taken from the
 /// SCE_PROSPERO_SDK_DIR environment variable.
+///
+/// In ThinLTO code generation mode (-fthinlto-index=) SDK files are not required
+/// so all warnings are suppressed.
 
 // RUN: echo "-### -Winvalid-or-nonexistent-directory -target x86_64-sie-ps5" > %t.rsp
 
@@ -33,6 +36,11 @@
 /// headers and libraries.
 // RUN: env SCE_PROSPERO_SDK_DIR=.. %clang @%t.rsp %s 2>&1 | FileCheck -check-prefixes=WARN-SYS-HEADERS,WARN-SYS-LIBS,NO-WARN %s
 
+/// -fthinlto-index= warning suppression.
+// RUN: %clang -O2 %s -flto=thin -c -o %t.o
+// RUN: llvm-lto -thinlto -o %t %t.o
+// RUN: env SCE_PROSPERO_SDK_DIR=.. %clang @%t.rsp %t.o -fthinlto-index=%t.thinlto.bc 2>&1 | FileCheck -check-prefixes=NO-WARN %s
+
 /// If `-c`, `-S`, `-E` or `-emit-ast` is supplied, the existence check for SDK
 /// libraries is skipped because no linking will be performed. We only expect
 /// warnings about missing headers.

[playstation-edd]

Is it realistic to have -fthinlto-index without also -c?

[bd1976bris]

It seems unlikely. I don't know what the use-case would be for that.

[bd1976bris]

Should we add the -c to make this more realistic?

[bd1976bris]

I've gone ahead and added it without waiting for your reply. My motivation is to reduce the delay for you here. This way if you approve of the PR in either the 799bcfe state or the d3e82d1 state you can indicate that.

[playstation-edd]

Thanks. Apologies for not expanding on the reasoning behind my query: since this change is motivated by the use of PS clang for remote codegen in a DTLTO context, it would seem sensible to ensure that situation is covered by the testing.