[PS4,PS5][Driver] Detangle --sysroot and -isysroot (#107410)

The following discrepancies concerning `-isysroot` and `--sysroot`
motivated this change:

- The SDK directory can be specified via `-isysroot`, but `--sysroot`
has no influence over this. Yet, we check for the presence of either
switch to determine whether we ought to warn about a missing SDK
*headers*.

- The presence of `-isysroot` is ignored when deciding whether to warn
about missing SDK *libraries*, depsite it being the only switch capable
of specifying a non-default SDK location.

- The `--sysroot`s passed to the PlayStation linkers by the driver are
unrelated to the SDK directory resolved in the PS4PS5Base constructor.

Following this change, we attempt to derive an SDK root from a platform-
specific environment variable. Failing that, we derive it from the location of
the driver. This then becomes the default root directory for both header and
library search. `--sysroot` overrides both search roots. `-isysroot` overrides
only the header search root. If both are specified, `--sysroot` specifies the
library search root and `-isysroot` specifies the header search root.

For each search root that was not overridden, a warning is emitted if expected
header/library search paths are missing inside that root.

The test updates to ps{4,5}-sdk-root.c were of the scale of a rewrite so
I also took the opportunity to clarify the purpose of each part,
eliminate some redundancy and add some missing coverage.

SIE tracker: TOOLCHAIN-16704

Author: playstation-edd

clang/lib/Driver/ToolChains/PS4CPU.cpp

@@ -135,8 +135,8 @@ void tools::PS4cpu::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   // handled somewhere else.
   Args.ClaimAllArgs(options::OPT_w);
 
-  if (!D.SysRoot.empty())
-    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+  CmdArgs.push_back(
+      Args.MakeArgString("--sysroot=" + TC.getSDKLibraryRootDir()));
 
   if (Args.hasArg(options::OPT_pie))
     CmdArgs.push_back("-pie");
@@ -234,8 +234,8 @@ void tools::PS5cpu::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   // handled somewhere else.
   Args.ClaimAllArgs(options::OPT_w);
 
-  if (!D.SysRoot.empty())
-    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+  CmdArgs.push_back(
+      Args.MakeArgString("--sysroot=" + TC.getSDKLibraryRootDir()));
 
   // Default to PIE for non-static executables.
   const bool PIE =
@@ -325,46 +325,63 @@ toolchains::PS4PS5Base::PS4PS5Base(const Driver &D, const llvm::Triple &Triple,
                                    const ArgList &Args, StringRef Platform,
                                    const char *EnvVar)
     : Generic_ELF(D, Triple, Args) {
-  // Determine where to find the PS4/PS5 libraries.
-  // If -isysroot was passed, use that as the SDK base path.
-  // If not, we use the EnvVar if it exists; otherwise use the driver's
-  // installation path, which should be <SDK_DIR>/host_tools/bin.
+  // Determine the baseline SDK directory from the environment, else
+  // the driver's location, which should be <SDK_DIR>/host_tools/bin.
+  SmallString<128> SDKRootDir;
   SmallString<80> Whence;
-  if (const Arg *A = Args.getLastArg(options::OPT_isysroot)) {
-    SDKRootDir = A->getValue();
-    if (!llvm::sys::fs::exists(SDKRootDir))
-      D.Diag(clang::diag::warn_missing_sysroot) << SDKRootDir;
-    Whence = A->getSpelling();
-  } else if (const char *EnvValue = getenv(EnvVar)) {
+  if (const char *EnvValue = getenv(EnvVar)) {
     SDKRootDir = EnvValue;
-    Whence = { "environment variable '", EnvVar, "'" };
+    Whence = {"environment variable '", EnvVar, "'"};
   } else {
     SDKRootDir = D.Dir + "/../../";
     Whence = "compiler's location";
   }
 
-  SmallString<512> SDKIncludeDir(SDKRootDir);
-  llvm::sys::path::append(SDKIncludeDir, "target/include");
-  if (!Args.hasArg(options::OPT_nostdinc) &&
-      !Args.hasArg(options::OPT_nostdlibinc) &&
-      !Args.hasArg(options::OPT_isysroot) &&
-      !Args.hasArg(options::OPT__sysroot_EQ) &&
-      !llvm::sys::fs::exists(SDKIncludeDir)) {
-    D.Diag(clang::diag::warn_drv_unable_to_find_directory_expected)
-        << Twine(Platform, " system headers").str() << SDKIncludeDir << Whence;
-  }
+  // Allow --sysroot= to override the root directory for header and library
+  // search, and -sysroot to override header search. If both are specified,
+  // -isysroot overrides --sysroot for header search.
+  auto OverrideRoot = [&](const options::ID &Opt, std::string &Root,
+                          StringRef Default) {
+    if (const Arg *A = Args.getLastArg(Opt)) {
+      Root = A->getValue();
+      if (!llvm::sys::fs::exists(Root))
+        D.Diag(clang::diag::warn_missing_sysroot) << Root;
+      return true;
+    }
+    Root = Default.str();
+    return false;
+  };
 
-  SmallString<512> SDKLibDir(SDKRootDir);
-  llvm::sys::path::append(SDKLibDir, "target/lib");
-  if (!Args.hasArg(options::OPT__sysroot_EQ) && !Args.hasArg(options::OPT_E) &&
-      !Args.hasArg(options::OPT_c) && !Args.hasArg(options::OPT_S) &&
-      !Args.hasArg(options::OPT_emit_ast) &&
-      !llvm::sys::fs::exists(SDKLibDir)) {
+  bool CustomSysroot =
+      OverrideRoot(options::OPT__sysroot_EQ, SDKLibraryRootDir, SDKRootDir);
+  bool CustomISysroot =
+      OverrideRoot(options::OPT_isysroot, SDKHeaderRootDir, SDKLibraryRootDir);
+
+  // Emit warnings if parts of the SDK are missing, unless the user has taken
+  // control of header or library search. If we're not linking, don't check
+  // for missing libraries.
+  auto CheckSDKPartExists = [&](StringRef Dir, StringRef Desc) {
+    if (llvm::sys::fs::exists(Dir))
+      return true;
     D.Diag(clang::diag::warn_drv_unable_to_find_directory_expected)
-        << Twine(Platform, " system libraries").str() << SDKLibDir << Whence;
-    return;
+        << (Twine(Platform) + " " + Desc).str() << Dir << Whence;
+    return false;
+  };
+
+  bool Linking = !Args.hasArg(options::OPT_E, options::OPT_c, options::OPT_S,
+                              options::OPT_emit_ast);
+  if (!CustomSysroot && Linking) {
+    SmallString<128> Dir(SDKLibraryRootDir);
+    llvm::sys::path::append(Dir, "target/lib");
+    if (CheckSDKPartExists(Dir, "system libraries"))
+      getFilePaths().push_back(std::string(Dir));
+  }
+  if (!CustomSysroot && !CustomISysroot &&
+      !Args.hasArg(options::OPT_nostdinc, options::OPT_nostdlibinc)) {
+    SmallString<128> Dir(SDKHeaderRootDir);
+    llvm::sys::path::append(Dir, "target/include");
+    CheckSDKPartExists(Dir, "system headers");
   }
-  getFilePaths().push_back(std::string(SDKLibDir));
 }
 
 void toolchains::PS4PS5Base::AddClangSystemIncludeArgs(
@@ -385,9 +402,9 @@ void toolchains::PS4PS5Base::AddClangSystemIncludeArgs(
     return;
 
   addExternCSystemInclude(DriverArgs, CC1Args,
-                          SDKRootDir + "/target/include");
+                          SDKHeaderRootDir + "/target/include");
   addExternCSystemInclude(DriverArgs, CC1Args,
-                          SDKRootDir + "/target/include_common");
+                          SDKHeaderRootDir + "/target/include_common");
 }
 
 Tool *toolchains::PS4CPU::buildAssembler() const {

clang/lib/Driver/ToolChains/PS4CPU.h

@@ -128,9 +128,12 @@ class LLVM_LIBRARY_VISIBILITY PS4PS5Base : public Generic_ELF {
                                 const char *Suffix) const = 0;
   virtual const char *getProfileRTLibName() const = 0;
 
+  StringRef getSDKLibraryRootDir() const { return SDKLibraryRootDir; }
+
 private:
-  // We compute the SDK root dir in the ctor, and use it later.
-  std::string SDKRootDir;
+  // We compute the SDK locations in the ctor, and use them later.
+  std::string SDKHeaderRootDir;
+  std::string SDKLibraryRootDir;
 };
 
 // PS4-specific Toolchain class.

clang/test/Driver/ps4-linker.c

@@ -28,3 +28,12 @@
 
 // RUN: %clang --target=x86_64-scei-ps4 %s -### 2>&1 | FileCheck --check-prefixes=CHECK-NO-LTO %s
 // CHECK-NO-LTO-NOT: -lto-debug-options
+
+// Test the driver passes a sysroot to the linker. Without --sysroot, its value
+// is sourced from the SDK environment variable.
+
+// RUN: env SCE_ORBIS_SDK_DIR=mysdk %clang --target=x64_64-scei-ps4 %s -### 2>&1 | FileCheck --check-prefixes=CHECK-SYSROOT %s
+// RUN: env SCE_ORBIS_SDK_DIR=other %clang --target=x64_64-scei-ps4 %s -### --sysroot=mysdk 2>&1 | FileCheck --check-prefixes=CHECK-SYSROOT %s
+
+// CHECK-SYSROOT: {{ld(\.exe)?}}"
+// CHECK-SYSROOT-SAME: "--sysroot=mysdk"

clang/test/Driver/ps4-ps5-header-search.c

@@ -1,6 +1,6 @@
 /// PS4 and PS5 use the same SDK layout, so use the same tree for both.
-// RUN: env SCE_ORBIS_SDK_DIR=%S/Inputs/scei-ps4_tree %clang -target x86_64-scei-ps4 --sysroot="" -E -v %s 2>&1 | FileCheck %s --check-prefix=ENVPS4
-// RUN: env SCE_PROSPERO_SDK_DIR=%S/Inputs/scei-ps4_tree %clang -target x86_64-sie-ps5 --sysroot="" -E -v %s 2>&1 | FileCheck %s --check-prefix=ENVPS4
+// RUN: env SCE_ORBIS_SDK_DIR=%S/Inputs/scei-ps4_tree %clang -target x86_64-scei-ps4 -E -v %s 2>&1 | FileCheck %s --check-prefix=ENVPS4
+// RUN: env SCE_PROSPERO_SDK_DIR=%S/Inputs/scei-ps4_tree %clang -target x86_64-sie-ps5 -E -v %s 2>&1 | FileCheck %s --check-prefix=ENVPS4
 // ENVPS4: Inputs/scei-ps4_tree/target/include
 // ENVPS4: Inputs/scei-ps4_tree/target/include_common
 // ENVPS4-NOT: /usr/include

clang/test/Driver/ps4-sdk-root.c

@@ -1,42 +1,67 @@
-// Check that PS4 clang doesn't report a warning message when locating
-// system header files (either by looking at the value of SCE_ORBIS_SDK_DIR
-// or relative to the location of the compiler driver), if "-nostdinc",
-// "--sysroot" or "-isysroot" option is specified on the command line.
-// Otherwise, check that PS4 clang reports a warning.
-
-// Check that PS4 clang doesn't report a warning message when locating
-// system libraries (either by looking at the value of SCE_ORBIS_SDK_DIR
-// or relative to the location of the compiler driver), if "-c", "-S", "-E"
-// or "--sysroot" option is specified on the command line.
-// Otherwise, check that PS4 clang reports a warning.
-
-// Setting up SCE_ORBIS_SDK_DIR to existing location, which is not a PS4 SDK.
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-SYS-HEADERS -check-prefix=WARN-SYS-LIBS -check-prefix=NO-WARN %s
-
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -c -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-SYS-HEADERS -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -S -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-SYS-HEADERS -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -E -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-SYS-HEADERS -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -emit-ast -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-SYS-HEADERS -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -isysroot foo -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-ISYSROOT -check-prefix=WARN-SYS-LIBS -check-prefix=NO-WARN %s
-
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -c -nostdinc -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -S -nostdinc -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -E -nostdinc -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -emit-ast -nostdinc -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=NO-WARN %s
-
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -c --sysroot=foo/ -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -S --sysroot=foo/ -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -E --sysroot=foo/ -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -emit-ast --sysroot=foo/ -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=NO-WARN %s
-
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -c -isysroot foo -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-ISYSROOT -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -S -isysroot foo -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-ISYSROOT -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -E -isysroot foo -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-ISYSROOT -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### -emit-ast -isysroot foo -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-ISYSROOT -check-prefix=NO-WARN %s
-// RUN: env SCE_ORBIS_SDK_DIR=.. %clang -Winvalid-or-nonexistent-directory -### --sysroot=foo/ -isysroot foo -target x86_64-scei-ps4 %s 2>&1 | FileCheck -check-prefix=WARN-ISYSROOT -check-prefix=NO-WARN %s
+/// PS4 clang emits warnings when SDK headers (<SDKROOT>/target/include/) or
+/// libraries (<SDKROOT>/target/lib/) are missing, unless the user takes control
+/// of search paths, when corresponding existence checks are skipped.
+///
+/// User control of header search is assumed if `--sysroot`, `-isysroot`,
+/// `-nostdinc` or `-nostdlibinc` is supplied. User control of library search
+/// is assumed if `--sysroot` is supplied.
+///
+/// Warnings are emitted if a specified `-isysroot` or `--sysroot` does not
+/// exist.
+///
+/// The default <SDKROOT> for both headers and libraries is taken from the
+/// SCE_ORBIS_SDK_DIR environment variable.
+
+// RUN: echo "-### -Winvalid-or-nonexistent-directory -target x86_64-scei-ps4" > %t.rsp
+
+/// If SDK headers and/or libraries are found, associated warnings are absent.
+// RUN: rm -rf %t.inconly && mkdir -p %t.inconly/target/include
+// RUN: env SCE_ORBIS_SDK_DIR=%t.inconly %clang @%t.rsp %s 2>&1 | FileCheck -check-prefixes=WARN-SYS-LIBS,NO-WARN %s
+
+// RUN: rm -rf %t.libonly && mkdir -p %t.libonly/target/lib
+// RUN: env SCE_ORBIS_SDK_DIR=%t.libonly %clang @%t.rsp %s 2>&1 | FileCheck -check-prefixes=WARN-SYS-HEADERS,NO-WARN %s
+
+// RUN: rm -rf %t.both && mkdir -p %t.both/target/lib && mkdir %t.both/target/include
+// RUN: env SCE_ORBIS_SDK_DIR=%t.both %clang @%t.rsp %s 2>&1 | FileCheck -check-prefix=NO-WARN %s
+
+/// In the following invocations, SCE_ORBIS_SDK_DIR is set to an existing
+/// location where SDK headers and libraries are absent.
+
+/// When compiling and linking, we should see a warnings about both missing
+/// 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
+
+/// 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.
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s -c 2>&1 | FileCheck -check-prefixes=WARN-SYS-HEADERS,NO-WARN %s
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s -S 2>&1 | FileCheck -check-prefixes=WARN-SYS-HEADERS,NO-WARN %s
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s -E 2>&1 | FileCheck -check-prefixes=WARN-SYS-HEADERS,NO-WARN %s
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s -emit-ast 2>&1 | FileCheck -check-prefixes=WARN-SYS-HEADERS,NO-WARN %s
+
+/// If the user takes control of include paths, the existence check for headers
+/// is not performed.
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s -c -nostdinc 2>&1 | FileCheck -check-prefix=NO-WARN %s
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s -c -nostdlibinc 2>&1 | FileCheck -check-prefix=NO-WARN %s
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s -c -isysroot . 2>&1 | FileCheck -check-prefixes=NO-WARN %s
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s -c --sysroot=. 2>&1 | FileCheck -check-prefixes=NO-WARN %s
+
+/// --sysroot disables the existence check for libraries and headers.
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s --sysroot=. 2>&1 | FileCheck -check-prefix=NO-WARN %s
+
+/// -isysroot overrides --sysroot for header search, but not library search.
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s -isysroot . --sysroot=.. 2>&1 | FileCheck -check-prefixes=ISYSTEM,NO-WARN %s
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s --sysroot=.. -isysroot . 2>&1 | FileCheck -check-prefixes=ISYSTEM,NO-WARN %s
+
+/// Warnings are emitted if non-existent --sysroot/-isysroot are supplied.
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s --sysroot=foo -isysroot . 2>&1 | FileCheck -check-prefixes=WARN-SYSROOT,NO-WARN %s
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s -isysroot foo --sysroot=. 2>&1 | FileCheck -check-prefixes=WARN-SYSROOT,NO-WARN %s
+// RUN: env SCE_ORBIS_SDK_DIR=.. %clang @%t.rsp %s --sysroot=foo -isysroot bar 2>&1 | FileCheck -check-prefixes=WARN-SYSROOT,WARN-SYSROOT2,NO-WARN %s
 
 // NO-WARN-NOT: {{warning:|error:}}
-// WARN-SYS-HEADERS: warning: unable to find PS4 system headers directory
-// WARN-ISYSROOT: warning: no such sysroot directory: 'foo'
 // WARN-SYS-LIBS: warning: unable to find PS4 system libraries directory
+// WARN-SYS-HEADERS: warning: unable to find PS4 system headers directory
+// WARN-SYSROOT: warning: no such sysroot directory: 'foo'
+// WARN-SYSROOT2: warning: no such sysroot directory: 'bar'
 // NO-WARN-NOT: {{warning:|error:}}
+// ISYSTEM: "-cc1"{{.*}}"-internal-externc-isystem" "./target/include"

clang/test/Driver/ps5-linker.c

@@ -37,3 +37,12 @@
 // RUN: %clang --target=x86_64-sie-ps5 -flto -fcrash-diagnostics-dir=mydumps %s -### 2>&1 | FileCheck --check-prefixes=CHECK-DIAG %s
 
 // CHECK-DIAG: -plugin-opt=-crash-diagnostics-dir=mydumps
+
+// Test the driver passes a sysroot to the linker. Without --sysroot, its value
+// is sourced from the SDK environment variable.
+
+// RUN: env SCE_PROSPERO_SDK_DIR=mysdk %clang --target=x64_64-sie-ps5 %s -### 2>&1 | FileCheck --check-prefixes=CHECK-SYSROOT %s
+// RUN: env SCE_PROSPERO_SDK_DIR=other %clang --target=x64_64-sie-ps5 %s -### --sysroot=mysdk 2>&1 | FileCheck --check-prefixes=CHECK-SYSROOT %s
+
+// CHECK-SYSROOT: {{ld(\.exe)?}}"
+// CHECK-SYSROOT-SAME: "--sysroot=mysdk"