[PATCH] D47600: [UBSan] DO NOT COMMIT: precise UBSan checks experiment

[Aleksey Shlyapnikov via Phabricator via cfe-commits]

alekseyshl created this revision.

clang part of the two part patch (LLVM + clang)

LLVM part: https://reviews.llvm.org/D47599

Refer to https://reviews.llvm.org/D47599 for the detailed description.


Repository:
  rC Clang

https://reviews.llvm.org/D47600

Files:
  include/clang/Driver/Options.td
  include/clang/Frontend/CodeGenOptions.def
  lib/CodeGen/CGExpr.cpp
  lib/Driver/ToolChains/Clang.cpp
  lib/Frontend/CompilerInvocation.cpp


Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1118,6 +1118,10 @@
 
   Opts.EmitVersionIdentMetadata = Args.hasFlag(OPT_Qy, OPT_Qn, true);
 
+  Opts.ExperimentalUseCondTrap = Args.hasFlag(
+      OPT_fexperimental_use_cond_trap, OPT_fno_experimental_use_cond_trap,
+      /* Default */ false);
+
   return Success;
 }
 
Index: lib/Driver/ToolChains/Clang.cpp
===================================================================
--- lib/Driver/ToolChains/Clang.cpp
+++ lib/Driver/ToolChains/Clang.cpp
@@ -4799,6 +4799,9 @@
       CmdArgs.push_back("-fforce-enable-int128");
   }
 
+  Args.AddLastArg(CmdArgs, options::OPT_fexperimental_use_cond_trap,
+                  options::OPT_fno_experimental_use_cond_trap);
+
   // Finally add the compile command to the compilation.
   if (Args.hasArg(options::OPT__SLASH_fallback) &&
       Output.getType() == types::TY_Object &&
Index: lib/CodeGen/CGExpr.cpp
===================================================================
--- lib/CodeGen/CGExpr.cpp
+++ lib/CodeGen/CGExpr.cpp
@@ -3131,18 +3131,25 @@
 void CodeGenFunction::EmitTrapCheck(llvm::Value *Checked) {
   llvm::BasicBlock *Cont = createBasicBlock("cont");
 
-  // If we're optimizing, collapse all calls to trap down to just one per
-  // function to save on code size.
-  if (!CGM.getCodeGenOpts().OptimizationLevel || !TrapBB) {
-    TrapBB = createBasicBlock("trap");
+  if (CGM.getCodeGenOpts().ExperimentalUseCondTrap) {
+    TrapBB = createBasicBlock("condtrap");
     Builder.CreateCondBr(Checked, Cont, TrapBB);
     EmitBlock(TrapBB);
-    llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap);
-    TrapCall->setDoesNotReturn();
-    TrapCall->setDoesNotThrow();
-    Builder.CreateUnreachable();
+    Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::condtrap));
   } else {
-    Builder.CreateCondBr(Checked, Cont, TrapBB);
+    // If we're optimizing, collapse all calls to trap down to just one per
+    // function to save on code size.
+    if (!CGM.getCodeGenOpts().OptimizationLevel || !TrapBB) {
+      TrapBB = createBasicBlock("trap");
+      Builder.CreateCondBr(Checked, Cont, TrapBB);
+      EmitBlock(TrapBB);
+      llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap);
+      TrapCall->setDoesNotReturn();
+      TrapCall->setDoesNotThrow();
+      Builder.CreateUnreachable();
+    } else {
+      Builder.CreateCondBr(Checked, Cont, TrapBB);
+    }
   }
 
   EmitBlock(Cont);
Index: include/clang/Frontend/CodeGenOptions.def
===================================================================
--- include/clang/Frontend/CodeGenOptions.def
+++ include/clang/Frontend/CodeGenOptions.def
@@ -332,6 +332,8 @@
 /// Whether to embed source in DWARF debug line section.
 CODEGENOPT(EmbedSource, 1, 0)
 
+CODEGENOPT(ExperimentalUseCondTrap, 1, 0)
+
 #undef CODEGENOPT
 #undef ENUM_CODEGENOPT
 #undef VALUE_CODEGENOPT
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -1102,6 +1102,10 @@
   Alias<fcf_protection_EQ>, AliasArgs<["full"]>,
   HelpText<"Enable cf-protection in 'full' mode">;
 
+def fexperimental_use_cond_trap : Flag<["-"], "fexperimental-use-cond-trap">,
+  Group<f_clang_Group>, Flags<[CC1Option]>,
+  HelpText<"Enables an experimental conditional trap in LLVM.">;
+
 def fxray_instrument : Flag<["-"], "fxray-instrument">, Group<f_Group>,
   Flags<[CC1Option]>,
   HelpText<"Generate XRay instrumentation sleds on function entry and exit">;
@@ -1437,6 +1441,10 @@
 def : Flag<["-"], "fno-aligned-new">, Alias<fno_aligned_allocation>;
 def faligned_new_EQ : Joined<["-"], "faligned-new=">;
 
+def fno_experimental_use_cond_trap : Flag<["-"], "fno-experimental-use-cond-trap">,
+  Group<f_clang_Group>, Flags<[CC1Option]>,
+  HelpText<"Disables an experimental conditional trap in LLVM.">;
+
 def fobjc_legacy_dispatch : Flag<["-"], "fobjc-legacy-dispatch">, Group<f_Group>;
 def fobjc_new_property : Flag<["-"], "fobjc-new-property">, Group<clang_ignored_f_Group>;
 def fobjc_infer_related_result_type : Flag<["-"], "fobjc-infer-related-result-type">,

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