[PATCH] D103943: [X86] Add -mgeneral-regs-only support.

[Wang Tianqing via Phabricator via cfe-commits]

tianqing created this revision.
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tianqing requested review of this revision.
Herald added a project: clang.
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Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D103943

Files:
  clang/include/clang/Driver/Options.td
  clang/lib/Basic/Targets/X86.cpp
  clang/lib/Driver/ToolChains/Arch/X86.cpp
  clang/test/CodeGen/attr-target-general-regs-only-x86.c
  clang/test/Driver/x86-mgeneral-regs-only.c


Index: clang/test/Driver/x86-mgeneral-regs-only.c
===================================================================
--- /dev/null
+++ clang/test/Driver/x86-mgeneral-regs-only.c
@@ -0,0 +1,8 @@
+// Test the -mgeneral-regs-only option on x86
+
+// RUN: %clang -target i386-unknown-linux-gnu -mgeneral-regs-only %s -### 2>&1 | FileCheck %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -mgeneral-regs-only %s -### 2>&1 | FileCheck %s
+
+// CHECK: "-target-feature" "-x87"
+// CHECK: "-target-feature" "-mmx"
+// CHECK: "-target-feature" "-sse"
Index: clang/test/CodeGen/attr-target-general-regs-only-x86.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/attr-target-general-regs-only-x86.c
@@ -0,0 +1,8 @@
+// Test general-regs-only target attribute on x86
+
+// RUN: %clang_cc1 -triple i386-unknown-linux-gnu -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o - | FileCheck %s
+
+void __attribute__((target("general-regs-only"))) foo() { }
+
+// CHECK: "target-features"="{{.*}}-mmx{{.*}}-sse{{.*}}-x87{{.*}}"
Index: clang/lib/Driver/ToolChains/Arch/X86.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Arch/X86.cpp
+++ clang/lib/Driver/ToolChains/Arch/X86.cpp
@@ -142,6 +142,12 @@
       Features.push_back("+ssse3");
   }
 
+  if (Args.getLastArg(options::OPT_mgeneral_regs_only)) {
+    Features.push_back("-x87");
+    Features.push_back("-mmx");
+    Features.push_back("-sse");
+  }
+
   // Translate the high level `-mretpoline` flag to the specific target feature
   // flags. We also detect if the user asked for retpoline external thunks but
   // failed to ask for retpolines themselves (through any of the different
Index: clang/lib/Basic/Targets/X86.cpp
===================================================================
--- clang/lib/Basic/Targets/X86.cpp
+++ clang/lib/Basic/Targets/X86.cpp
@@ -142,6 +142,17 @@
       llvm::find(FeaturesVec, "-xsave") == FeaturesVec.end())
     Features["xsave"] = true;
 
+  I = Features.find("general-regs-only");
+  if (I != Features.end()) {
+    bool HasGeneralRegsOnly = I->getValue();
+    Features.erase(I);
+    if (HasGeneralRegsOnly) {
+      setFeatureEnabled(Features, "x87", false);
+      setFeatureEnabled(Features, "mmx", false);
+      setFeatureEnabled(Features, "sse", false);
+    }
+  }
+
   return true;
 }
 
@@ -865,6 +876,7 @@
       .Case("fma4", true)
       .Case("fsgsbase", true)
       .Case("fxsr", true)
+      .Case("general-regs-only", true)
       .Case("gfni", true)
       .Case("hreset", true)
       .Case("invpcid", true)
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -3197,8 +3197,8 @@
             " volatile bit-field width is dictated by the field container type. (ARM only).">>,
   Group<m_arm_Features_Group>;
 
-def mgeneral_regs_only : Flag<["-"], "mgeneral-regs-only">, Group<m_aarch64_Features_Group>,
-  HelpText<"Generate code which only uses the general purpose registers (AArch64 only)">;
+def mgeneral_regs_only : Flag<["-"], "mgeneral-regs-only">, Group<m_Group>,
+  HelpText<"Generate code which only uses the general purpose registers (AArch64/x86 only)">;
 def mfix_cortex_a53_835769 : Flag<["-"], "mfix-cortex-a53-835769">,
   Group<m_aarch64_Features_Group>,
   HelpText<"Workaround Cortex-A53 erratum 835769 (AArch64 only)">;


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