Merging r323485:

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r323485 | aemerson | 2018-01-26 01:27:22 +0100 (Fri, 26 Jan 2018) | 3 lines

[Driver] Add an -fexperimental-isel driver option to enable/disable GlobalISel.

Differential Revision: https://reviews.llvm.org/D42276
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_60@323745 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 70 insertions, 0 deletions

diff --git a/include/clang/Basic/DiagnosticDriverKinds.td b/include/clang/Basic/DiagnosticDriverKinds.td
index 45cdf82d36..28aead0cdb 100644
--- a/include/clang/Basic/DiagnosticDriverKinds.td
+++ b/include/clang/Basic/DiagnosticDriverKinds.td
@@ -354,4 +354,12 @@ def warn_drv_fine_grained_bitfield_accesses_ignored : Warning<
 def note_drv_verify_prefix_spelling : Note<
   "-verify prefixes must start with a letter and contain only alphanumeric"
   " characters, hyphens, and underscores">;
+
+def warn_drv_experimental_isel_incomplete : Warning<
+  "-fexperimental-isel support for the '%0' architecture is incomplete">,
+  InGroup<ExperimentalISel>;
+
+def warn_drv_experimental_isel_incomplete_opt : Warning<
+  "-fexperimental-isel support is incomplete for this architecture at the current optimization level">,
+  InGroup<ExperimentalISel>;
 }
diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index b54f075088..2d471f1fa5 100644
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -985,3 +985,6 @@ def UnknownArgument : DiagGroup<"unknown-argument">;
 // A warning group for warnings about code that clang accepts when
 // compiling OpenCL C/C++ but which is not compatible with the SPIR spec.
 def SpirCompat : DiagGroup<"spir-compat">;
+
+// Warning for the experimental-isel options.
+def ExperimentalISel : DiagGroup<"experimental-isel">;
diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 3ee834e685..74e13f7026 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -1031,6 +1031,8 @@ def finline_functions : Flag<["-"], "finline-functions">, Group<f_clang_Group>,
 def finline_hint_functions: Flag<["-"], "finline-hint-functions">, Group<f_clang_Group>, Flags<[CC1Option]>,
   HelpText<"Inline functions which are (explicitly or implicitly) marked inline">;
 def finline : Flag<["-"], "finline">, Group<clang_ignored_f_Group>;
+def fexperimental_isel : Flag<["-"], "fexperimental-isel">, Group<f_clang_Group>,
+  HelpText<"Enables the experimental global instruction selector">;
 def fexperimental_new_pass_manager : Flag<["-"], "fexperimental-new-pass-manager">,
   Group<f_clang_Group>, Flags<[CC1Option]>,
   HelpText<"Enables an experimental new pass manager in LLVM.">;
@@ -1237,6 +1239,8 @@ def fno_exceptions : Flag<["-"], "fno-exceptions">, Group<f_Group>;
 def fno_gnu_keywords : Flag<["-"], "fno-gnu-keywords">, Group<f_Group>, Flags<[CC1Option]>;
 def fno_inline_functions : Flag<["-"], "fno-inline-functions">, Group<f_clang_Group>, Flags<[CC1Option]>;
 def fno_inline : Flag<["-"], "fno-inline">, Group<f_clang_Group>, Flags<[CC1Option]>;
+def fno_experimental_isel : Flag<["-"], "fno-experimental-isel">, Group<f_clang_Group>,
+  HelpText<"Disables the experimental global instruction selector">;
 def fno_experimental_new_pass_manager : Flag<["-"], "fno-experimental-new-pass-manager">,
   Group<f_clang_Group>, Flags<[CC1Option]>,
   HelpText<"Disables an experimental new pass manager in LLVM.">;
diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp
index c445669a5a..484df52001 100644
--- a/lib/Driver/ToolChains/Clang.cpp
+++ b/lib/Driver/ToolChains/Clang.cpp
@@ -4639,6 +4639,37 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-fwhole-program-vtables");
   }
 
+  if (Arg *A = Args.getLastArg(options::OPT_fexperimental_isel,
+                               options::OPT_fno_experimental_isel)) {
+    CmdArgs.push_back("-mllvm");
+    if (A->getOption().matches(options::OPT_fexperimental_isel)) {
+      CmdArgs.push_back("-global-isel=1");
+
+      // GISel is on by default on AArch64 -O0, so don't bother adding
+      // the fallback remarks for it. Other combinations will add a warning of
+      // some kind.
+      bool IsArchSupported = Triple.getArch() == llvm::Triple::aarch64;
+      bool IsOptLevelSupported = false;
+
+      Arg *A = Args.getLastArg(options::OPT_O_Group);
+      if (Triple.getArch() == llvm::Triple::aarch64) {
+        if (!A || A->getOption().matches(options::OPT_O0))
+          IsOptLevelSupported = true;
+      }
+      if (!IsArchSupported || !IsOptLevelSupported) {
+        CmdArgs.push_back("-mllvm");
+        CmdArgs.push_back("-global-isel-abort=2");
+
+        if (!IsArchSupported)
+          D.Diag(diag::warn_drv_experimental_isel_incomplete) << Triple.getArchName();
+        else
+          D.Diag(diag::warn_drv_experimental_isel_incomplete_opt);
+      }
+    } else {
+      CmdArgs.push_back("-global-isel=0");
+    }
+  }
+
   // Finally add the compile command to the compilation.
   if (Args.hasArg(options::OPT__SLASH_fallback) &&
       Output.getType() == types::TY_Object &&
diff --git a/test/Driver/global-isel.c b/test/Driver/global-isel.c
new file mode 100644
index 0000000000..f4fc6a758a
--- /dev/null
+++ b/test/Driver/global-isel.c
@@ -0,0 +1,24 @@
+// REQUIRES: x86-registered-target,aarch64-registered-target
+
+// RUN: %clang -fexperimental-isel -S -### %s 2>&1 | FileCheck --check-prefix=ENABLED %s
+// RUN: %clang -fno-experimental-isel -S -### %s 2>&1 | FileCheck --check-prefix=DISABLED %s
+
+// RUN: %clang -target aarch64 -fexperimental-isel -S %s -### 2>&1 | FileCheck --check-prefix=ARM64-DEFAULT %s
+// RUN: %clang -target aarch64 -fexperimental-isel -S -O0 %s -### 2>&1 | FileCheck --check-prefix=ARM64-O0 %s
+// RUN: %clang -target aarch64 -fexperimental-isel -S -O2 %s -### 2>&1 | FileCheck --check-prefix=ARM64-O2 %s
+// RUN: %clang -target aarch64 -fexperimental-isel -Wno-experimental-isel -S -O2 %s -### 2>&1 | FileCheck --check-prefix=ARM64-O2-NOWARN %s
+
+// RUN: %clang -target x86_64 -fexperimental-isel -S %s -### 2>&1 | FileCheck --check-prefix=X86_64 %s
+
+// ENABLED: "-mllvm" "-global-isel=1"
+// DISABLED: "-mllvm" "-global-isel=0"
+
+// ARM64-DEFAULT-NOT: warning: -fexperimental-sel
+// ARM64-DEFAULT-NOT: "-global-isel-abort=2"
+// ARM64-O0-NOT: warning: -fexperimental-sel
+// ARM64-O2: warning: -fexperimental-isel support is incomplete for this architecture at the current optimization level
+// ARM64-O2: "-mllvm" "-global-isel-abort=2"
+// ARM64-O2-NOWARN-NOT: warning: -fexperimental-isel
+
+// X86_64: -fexperimental-isel support for the 'x86_64' architecture is incomplete
+// X86_64: "-mllvm" "-global-isel-abort=2"