[PATCH] D15208: Patch for inline abort code generation

[Dan Austin via cfe-commits]

danielaustin updated this revision to Diff 42328.
danielaustin added a comment.

Patch that removes the debug-mode sanitizer setting and makes the -fsanitize-merge-traps/-fno-sanitize-merge-traps flags, with the default setting being to merge traps. Flags tested within the Android build system, with presence and absence of flags both working as expected.


Repository:
  rL LLVM

http://reviews.llvm.org/D15208

Files:
  include/clang/Basic/LangOptions.h
  include/clang/Driver/Options.td
  lib/CodeGen/CGExpr.cpp
  lib/Frontend/CompilerInvocation.cpp

Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1569,6 +1569,12 @@
   if (Args.hasArg(OPT_fvisibility_inlines_hidden))
     Opts.InlineVisibilityHidden = 1;
 
+  if (Args.hasArg(OPT_fno_sanitize_merge_traps)) {
+    Opts.mergeTraps = false;
+  } else {
+    Opts.mergeTraps = true;
+  }
+
   if (Args.hasArg(OPT_ftrapv)) {
     Opts.setSignedOverflowBehavior(LangOptions::SOB_Trapping);
     // Set the handler, if one is specified.
Index: lib/CodeGen/CGExpr.cpp
===================================================================
--- lib/CodeGen/CGExpr.cpp
+++ lib/CodeGen/CGExpr.cpp
@@ -27,6 +27,7 @@
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/IR/DataLayout.h"
+#include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/MDBuilder.h"
@@ -2535,9 +2536,25 @@
 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) {
+  // Collapsing all calls to trap down to one per function makes debugging
+  // these issues much more difficult. Eliminating this optimization 
+  // for debugging purposes.
+  // RE: Bug: 25682
+  if(!getLangOpts().mergeTraps) {
+      llvm::InlineAsm *EmptyAsm = llvm::InlineAsm::get(llvm::FunctionType::get(CGM.VoidTy, false), 
+						       StringRef(""), StringRef(""), true);
+      TrapBB = createBasicBlock("trap");
+      Builder.CreateCondBr(Checked, Cont, TrapBB);
+      EmitBlock(TrapBB);
+      llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap);
+      TrapCall->setDoesNotReturn();
+      TrapCall->setDoesNotThrow();
+      Builder.CreateUnreachable();
+      //this stops the trap calls from being merged at the end of the function
+      Builder.CreateCall(EmptyAsm, {});
+  } else if(!CGM.getCodeGenOpts().OptimizationLevel || !TrapBB) {
+    // If we're optimizing, collapse all calls to trap down to just one per
+    // function to save on code size.
     TrapBB = createBasicBlock("trap");
     Builder.CreateCondBr(Checked, Cont, TrapBB);
     EmitBlock(TrapBB);
@@ -2548,7 +2565,7 @@
   } else {
     Builder.CreateCondBr(Checked, Cont, TrapBB);
   }
-
+  
   EmitBlock(Cont);
 }
 
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -607,6 +607,12 @@
     : CommaJoined<["-"], "fno-sanitize-recover=">,
       Group<f_clang_Group>, Flags<[CoreOption]>,
       HelpText<"Disable recovery for specified sanitizers">;
+def fsanitize_merge_traps : Flag<["-"], "fsanitize-merge-traps">, 
+                            Group<f_clang_Group>,
+                            HelpText<"Merge all traps for sanitizers to one per function.">; 
+def fno_sanitize_merge_traps : Flag<["-"], "fno-sanitize-merge-traps">, 
+                               Group<f_clang_Group>,
+                               HelpText<"Generate traps for sanitizers inline to aid in debugging.">; 
 def fsanitize_trap_EQ : CommaJoined<["-"], "fsanitize-trap=">, Group<f_clang_Group>,
                         Flags<[CC1Option, CoreOption]>,
                         HelpText<"Enable trapping for specified sanitizers">;
Index: include/clang/Basic/LangOptions.h
===================================================================
--- include/clang/Basic/LangOptions.h
+++ include/clang/Basic/LangOptions.h
@@ -92,6 +92,10 @@
   /// If none is specified, abort (GCC-compatible behaviour).
   std::string OverflowHandler;
 
+  /// \brief Flag controlling whether or not trap calls are merged
+  /// at the end of each function.
+  bool mergeTraps;
+
   /// \brief The name of the current module.
   std::string CurrentModule;
 


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