[PATCH] D18407: Add -fno-jump-tables and-fjump-tables flags

[Nirav Dave via llvm-commits]

niravd updated this revision to Diff 51925.
niravd marked an inline comment as done.
niravd added a comment.

Simplify test


http://reviews.llvm.org/D18407

Files:
  include/clang/Driver/Options.td
  include/clang/Frontend/CodeGenOptions.def
  lib/CodeGen/CodeGenFunction.cpp
  lib/Driver/Tools.cpp
  lib/Frontend/CompilerInvocation.cpp
  test/CodeGen/nousejumptable.c

Index: test/CodeGen/nousejumptable.c
===================================================================
--- /dev/null
+++ test/CodeGen/nousejumptable.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -S -fno-jump-tables %s -emit-llvm -o - | FileCheck %s
+
+// CHECK-LABEL: main
+// CHECK: attributes #0 = {{.*}}"no-jump-tables"="true"{{.*}}
+
+int main() {
+  return 0;
+}
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -606,6 +606,8 @@
 
   Opts.MergeFunctions = Args.hasArg(OPT_fmerge_functions);
 
+  Opts.NoUseJumpTables = Args.hasArg(OPT_fno_jump_tables);
+
   Opts.PrepareForLTO = Args.hasArg(OPT_flto, OPT_flto_EQ);
   const Arg *A = Args.getLastArg(OPT_flto, OPT_flto_EQ);
   Opts.EmitSummaryIndex = A && A->containsValue("thin");
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -3892,6 +3892,10 @@
     A->claim();
   }
 
+  if (!Args.hasFlag(options::OPT_fjump_tables, options::OPT_fno_jump_tables,
+                    true))
+    CmdArgs.push_back("-fno-jump-tables");
+
   if (Arg *A = Args.getLastArg(options::OPT_mregparm_EQ)) {
     CmdArgs.push_back("-mregparm");
     CmdArgs.push_back(A->getValue());
Index: lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- lib/CodeGen/CodeGenFunction.cpp
+++ lib/CodeGen/CodeGenFunction.cpp
@@ -711,6 +711,10 @@
       Fn->addFnAttr(llvm::Attribute::NoInline);
   }
 
+  // Add no-jump-tables value.
+  Fn->addFnAttr("no-jump-tables",
+                llvm::toStringRef(CGM.getCodeGenOpts().NoUseJumpTables));
+
   if (getLangOpts().OpenCL) {
     // Add metadata for a kernel function.
     if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
Index: include/clang/Frontend/CodeGenOptions.def
===================================================================
--- include/clang/Frontend/CodeGenOptions.def
+++ include/clang/Frontend/CodeGenOptions.def
@@ -149,6 +149,7 @@
                                      ///< selection.
 CODEGENOPT(UnrollLoops       , 1, 0) ///< Control whether loops are unrolled.
 CODEGENOPT(RerollLoops       , 1, 0) ///< Control whether loops are rerolled.
+CODEGENOPT(NoUseJumpTables   , 1, 0) ///< Set when -fno-jump-tables is enabled
 CODEGENOPT(UnsafeFPMath      , 1, 0) ///< Allow unsafe floating point optzns.
 CODEGENOPT(UnwindTables      , 1, 0) ///< Emit unwind tables.
 CODEGENOPT(VectorizeBB       , 1, 0) ///< Run basic block vectorizer.
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -586,6 +586,9 @@
 def fbracket_depth_EQ : Joined<["-"], "fbracket-depth=">, Group<f_Group>;
 def fsignaling_math : Flag<["-"], "fsignaling-math">, Group<f_Group>;
 def fno_signaling_math : Flag<["-"], "fno-signaling-math">, Group<f_Group>;
+def fjump_tables : Flag<["-"], "fjump-tables">, Group<f_Group>;
+def fno_jump_tables : Flag<["-"], "fno-jump-tables">, Group<f_Group>, Flags<[CC1Option]>,
+  HelpText<"Do not use jump tables for lowering switches">;
 def fsanitize_EQ : CommaJoined<["-"], "fsanitize=">, Group<f_clang_Group>,
                    Flags<[CC1Option, CoreOption]>, MetaVarName<"<check>">,
                    HelpText<"Turn on runtime checks for various forms of undefined "


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