[BOLT][AArch64] Allow binary-analysis and heatmap tool to run with pac-ret binaries (#136664)

OpNegateRAState support is only needed for tools that produce binaries.

Author: bgergely0

bolt/docs/BinaryAnalysis.md

@@ -180,12 +180,6 @@ The following are current known cases of false negatives:
    [prototype branch](
    https://github.com/llvm/llvm-project/compare/main...kbeyls:llvm-project:bolt-gadget-scanner-prototype).
 
-BOLT cannot currently handle functions with `cfi_negate_ra_state` correctly,
-i.e. any binaries built with `-mbranch-protection=pac-ret`. The scanner is meant
-to be used on specifically such binaries, so this is a major limitation! Work is
-going on in PR [#120064](https://github.com/llvm/llvm-project/pull/120064) to
-fix this.
-
 ## How to add your own binary analysis
 
 _TODO: this section needs to be written. Ideally, we should have a simple

bolt/lib/Core/BinaryFunction.cpp

@@ -65,6 +65,8 @@ extern cl::opt<bool> StrictMode;
 extern cl::opt<bool> UpdateDebugSections;
 extern cl::opt<unsigned> Verbosity;
 
+extern bool BinaryAnalysisMode;
+extern bool HeatmapMode;
 extern bool processAllFunctions();
 
 static cl::opt<bool> CheckEncoding(
@@ -2760,13 +2762,19 @@ struct CFISnapshot {
     }
     case MCCFIInstruction::OpAdjustCfaOffset:
     case MCCFIInstruction::OpWindowSave:
-    case MCCFIInstruction::OpNegateRAState:
     case MCCFIInstruction::OpNegateRAStateWithPC:
     case MCCFIInstruction::OpLLVMDefAspaceCfa:
     case MCCFIInstruction::OpLabel:
     case MCCFIInstruction::OpValOffset:
       llvm_unreachable("unsupported CFI opcode");
       break;
+    case MCCFIInstruction::OpNegateRAState:
+      if (!(opts::BinaryAnalysisMode || opts::HeatmapMode)) {
+        llvm_unreachable("BOLT-ERROR: binaries using pac-ret hardening (e.g. "
+                         "as produced by '-mbranch-protection=pac-ret') are "
+                         "currently not supported by BOLT.");
+      }
+      break;
     case MCCFIInstruction::OpRememberState:
     case MCCFIInstruction::OpRestoreState:
     case MCCFIInstruction::OpGnuArgsSize:
@@ -2900,13 +2908,19 @@ struct CFISnapshotDiff : public CFISnapshot {
       return CFAReg == Instr.getRegister() && CFAOffset == Instr.getOffset();
     case MCCFIInstruction::OpAdjustCfaOffset:
     case MCCFIInstruction::OpWindowSave:
-    case MCCFIInstruction::OpNegateRAState:
     case MCCFIInstruction::OpNegateRAStateWithPC:
     case MCCFIInstruction::OpLLVMDefAspaceCfa:
     case MCCFIInstruction::OpLabel:
     case MCCFIInstruction::OpValOffset:
       llvm_unreachable("unsupported CFI opcode");
       return false;
+    case MCCFIInstruction::OpNegateRAState:
+      if (!(opts::BinaryAnalysisMode || opts::HeatmapMode)) {
+        llvm_unreachable("BOLT-ERROR: binaries using pac-ret hardening (e.g. "
+                         "as produced by '-mbranch-protection=pac-ret') are "
+                         "currently not supported by BOLT.");
+      }
+      break;
     case MCCFIInstruction::OpRememberState:
     case MCCFIInstruction::OpRestoreState:
     case MCCFIInstruction::OpGnuArgsSize:
@@ -3051,13 +3065,19 @@ BinaryFunction::unwindCFIState(int32_t FromState, int32_t ToState,
       break;
     case MCCFIInstruction::OpAdjustCfaOffset:
     case MCCFIInstruction::OpWindowSave:
-    case MCCFIInstruction::OpNegateRAState:
     case MCCFIInstruction::OpNegateRAStateWithPC:
     case MCCFIInstruction::OpLLVMDefAspaceCfa:
     case MCCFIInstruction::OpLabel:
     case MCCFIInstruction::OpValOffset:
       llvm_unreachable("unsupported CFI opcode");
       break;
+    case MCCFIInstruction::OpNegateRAState:
+      if (!(opts::BinaryAnalysisMode || opts::HeatmapMode)) {
+        llvm_unreachable("BOLT-ERROR: binaries using pac-ret hardening (e.g. "
+                         "as produced by '-mbranch-protection=pac-ret') are "
+                         "currently not supported by BOLT.");
+      }
+      break;
     case MCCFIInstruction::OpGnuArgsSize:
       // do not affect CFI state
       break;