[PATCH] D140080: [clang][PPC] Supporting -mcpu=405

[Qiongsi Wu via Phabricator via cfe-commits]

qiongsiwu1 created this revision.
qiongsiwu1 added a reviewer: nemanjai.
qiongsiwu1 added projects: PowerPC, clang.
Herald added subscribers: shchenz, kbarton.
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Herald added subscribers: cfe-commits, MaskRay.

The  ClangBuiltLinux  project relies on `-mcpu=405`. Before https://reviews.llvm.org/D139720, `clang` treated `-mcpu=405` implicitly in the same way as `-mcpu=generic`, because `405` was an unknown value and `clang` did not check unknown input values. https://reviews.llvm.org/D139720 added the check of `-mcpu` input value, and `clang` generates an error with `-mcpu=405`. For further details of the problem, see https://github.com/ClangBuiltLinux/linux/issues/1771.

This patch adds support of `-mcpu=405` explicitly, and treats it as an equivalent of `-mcpu=generic`.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D140080

Files:
  clang/lib/Driver/ToolChains/Arch/PPC.cpp
  clang/test/Driver/ppc-cpus.c


Index: clang/test/Driver/ppc-cpus.c
===================================================================
--- clang/test/Driver/ppc-cpus.c
+++ clang/test/Driver/ppc-cpus.c
@@ -31,3 +31,9 @@
 
 // RUN: %clang -### -c --target=powerpc64 %s -mcpu=generic -mtune=pwr9 2>&1 | FileCheck %s --check-prefix=TUNE
 // TUNE: "-target-cpu" "ppc64" "-tune-cpu" "pwr9"
+
+/// Test mcpu options that are equivalent to "generic"
+// RUN: %clang -### -c -target powerpc64 %s -mcpu=generic 2>&1 | FileCheck %s --check-prefix=GENERIC
+// RUN: %clang -### -c -target powerpc64 %s -mcpu=405     2>&1 | FileCheck %s --check-prefix=GENERIC
+//
+// GENERIC: "-target-cpu" "ppc64"
Index: clang/lib/Driver/ToolChains/Arch/PPC.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Arch/PPC.cpp
+++ clang/lib/Driver/ToolChains/Arch/PPC.cpp
@@ -20,6 +20,14 @@
 using namespace clang;
 using namespace llvm::opt;
 
+static constexpr llvm::StringLiteral GenericPPCTargetNames[] = {{"generic"},
+                                                                {"405"}};
+
+/// Check if Name is known to be equivalent to "generic".
+static bool isGenericPPCTargetName(const StringRef &Name) {
+  return llvm::is_contained(GenericPPCTargetNames, Name);
+}
+
 static std::string getPPCGenericTargetCPU(const llvm::Triple &T) {
   // LLVM may default to generating code for the native CPU,
   // but, like gcc, we default to a more generic option for
@@ -39,7 +47,7 @@
   if (Arg *A = Args.getLastArg(clang::driver::options::OPT_mcpu_EQ)) {
     StringRef CPUName = A->getValue();
 
-    if (CPUName == "generic")
+    if (isGenericPPCTargetName(CPUName))
       return getPPCGenericTargetCPU(T);
 
     if (CPUName == "native") {


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