[Lldb-commits] [lldb] 9821632 - [lldb] [Process/NetBSD] Fix crash on unsupported i386 regs
Michał Górny via lldb-commits
lldb-commits at lists.llvm.org
Sat Oct 3 10:54:52 PDT 2020
Author: Michał Górny
Date: 2020-10-03T19:54:38+02:00
New Revision: 9821632056dce9e2150bab9c0fbd9b2c7da64258
URL: https://github.com/llvm/llvm-project/commit/9821632056dce9e2150bab9c0fbd9b2c7da64258
DIFF: https://github.com/llvm/llvm-project/commit/9821632056dce9e2150bab9c0fbd9b2c7da64258.diff
LOG: [lldb] [Process/NetBSD] Fix crash on unsupported i386 regs
Multiple fixes related to bugs discovered while debugging a crash
when reading all registers on i386.
The underlying problem was that GetSetForNativeRegNum() did not account
for MPX registers on i386, and since it only compared against upper
bounds of each known register set, the MPX registers were classified
into the wrong set and therefore considered supported. However, they
were not expected in RegNumX86ToX86_64() and caused the assertion
to fail.
This includes:
- adding (unused) i386 → x86_64 translations for MPX registers
- fixing GetSetForNativeRegNum() to check both lower and upper bound
for register sets, to avoid wrongly classifying unhandled register
sets
- adding missing range check for MPX registers on i386
- renaming k_last_mpxr to k_last_mpxr_i386 for consistency
- replacing return-assertions with llvm_unreachable() and adding more
checks for unexpected parameters
Differential Revision: https://reviews.llvm.org/D88682
Added:
Modified:
lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp
lldb/source/Plugins/Process/Utility/lldb-x86-register-enums.h
Removed:
################################################################################
diff --git a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp
index 089ae4ffff2f..cb1e883258b5 100644
--- a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp
+++ b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp
@@ -278,11 +278,8 @@ NativeRegisterContextNetBSD_x86_64::GetRegisterSet(uint32_t set_index) const {
case llvm::Triple::x86_64:
return &g_reg_sets_x86_64[set_index];
default:
- assert(false && "Unhandled target architecture.");
- return nullptr;
+ llvm_unreachable("Unhandled target architecture.");
}
-
- return nullptr;
}
static constexpr int RegNumX86ToX86_64(int regnum) {
@@ -375,6 +372,15 @@ static constexpr int RegNumX86ToX86_64(int regnum) {
case lldb_ymm6_i386:
case lldb_ymm7_i386:
return lldb_ymm0_x86_64 + regnum - lldb_ymm0_i386;
+ case lldb_bnd0_i386:
+ case lldb_bnd1_i386:
+ case lldb_bnd2_i386:
+ case lldb_bnd3_i386:
+ return lldb_bnd0_x86_64 + regnum - lldb_bnd0_i386;
+ case lldb_bndcfgu_i386:
+ return lldb_bndcfgu_x86_64;
+ case lldb_bndstatus_i386:
+ return lldb_bndstatus_x86_64;
case lldb_dr0_i386:
case lldb_dr1_i386:
case lldb_dr2_i386:
@@ -385,8 +391,7 @@ static constexpr int RegNumX86ToX86_64(int regnum) {
case lldb_dr7_i386:
return lldb_dr0_x86_64 + regnum - lldb_dr0_i386;
default:
- assert(false && "Unhandled i386 register.");
- return 0;
+ llvm_unreachable("Unhandled i386 register.");
}
}
@@ -394,35 +399,38 @@ int NativeRegisterContextNetBSD_x86_64::GetSetForNativeRegNum(
int reg_num) const {
switch (GetRegisterInfoInterface().GetTargetArchitecture().GetMachine()) {
case llvm::Triple::x86:
- if (reg_num <= k_last_gpr_i386)
+ if (reg_num >= k_first_gpr_i386 && reg_num <= k_last_gpr_i386)
return GPRegSet;
- else if (reg_num <= k_last_fpr_i386)
+ if (reg_num >= k_first_fpr_i386 && reg_num <= k_last_fpr_i386)
return FPRegSet;
- else if (reg_num <= k_last_avx_i386)
+ if (reg_num >= k_first_avx_i386 && reg_num <= k_last_avx_i386)
return XStateRegSet; // AVX
- else if (reg_num <= lldb_dr7_i386)
+ if (reg_num >= k_first_mpxr_i386 && reg_num <= k_last_mpxr_i386)
+ return -1; // MPXR
+ if (reg_num >= k_first_mpxc_i386 && reg_num <= k_last_mpxc_i386)
+ return -1; // MPXC
+ if (reg_num >= k_first_dbr_i386 && reg_num <= k_last_dbr_i386)
return DBRegSet; // DBR
- else
- return -1;
+ break;
case llvm::Triple::x86_64:
- if (reg_num <= k_last_gpr_x86_64)
+ if (reg_num >= k_first_gpr_x86_64 && reg_num <= k_last_gpr_x86_64)
return GPRegSet;
- else if (reg_num <= k_last_fpr_x86_64)
+ if (reg_num >= k_first_fpr_x86_64 && reg_num <= k_last_fpr_x86_64)
return FPRegSet;
- else if (reg_num <= k_last_avx_x86_64)
+ if (reg_num >= k_first_avx_x86_64 && reg_num <= k_last_avx_x86_64)
return XStateRegSet; // AVX
- else if (reg_num <= k_last_mpxr_x86_64)
+ if (reg_num >= k_first_mpxr_x86_64 && reg_num <= k_last_mpxr_x86_64)
return -1; // MPXR
- else if (reg_num <= k_last_mpxc_x86_64)
+ if (reg_num >= k_first_mpxc_x86_64 && reg_num <= k_last_mpxc_x86_64)
return -1; // MPXC
- else if (reg_num <= lldb_dr7_x86_64)
+ if (reg_num >= k_first_dbr_x86_64 && reg_num <= k_last_dbr_x86_64)
return DBRegSet; // DBR
- else
- return -1;
+ break;
default:
- assert(false && "Unhandled target architecture.");
- return -1;
+ llvm_unreachable("Unhandled target architecture.");
}
+
+ llvm_unreachable("Register does not belong to any register set");
}
Status NativeRegisterContextNetBSD_x86_64::ReadRegisterSet(uint32_t set) {
@@ -511,9 +519,7 @@ NativeRegisterContextNetBSD_x86_64::ReadRegister(const RegisterInfo *reg_info,
reg = RegNumX86ToX86_64(reg);
break;
default:
- assert(false && "Unhandled target architecture.");
- error.SetErrorString("Unhandled target architecture.");
- return error;
+ llvm_unreachable("Unhandled target architecture.");
}
error = ReadRegisterSet(set);
@@ -758,6 +764,8 @@ NativeRegisterContextNetBSD_x86_64::ReadRegister(const RegisterInfo *reg_info,
case lldb_dr7_x86_64:
reg_value = (uint64_t)m_dbr.dr[reg - lldb_dr0_x86_64];
break;
+ default:
+ llvm_unreachable("Reading unknown/unsupported register");
}
return error;
@@ -799,9 +807,7 @@ Status NativeRegisterContextNetBSD_x86_64::WriteRegister(
reg = RegNumX86ToX86_64(reg);
break;
default:
- assert(false && "Unhandled target architecture.");
- error.SetErrorString("Unhandled target architecture.");
- return error;
+ llvm_unreachable("Unhandled target architecture.");
}
error = ReadRegisterSet(set);
@@ -1034,6 +1040,7 @@ Status NativeRegisterContextNetBSD_x86_64::WriteRegister(
}
#else
error.SetErrorString("XState not supported by the kernel");
+ return error;
#endif
break;
case lldb_dr0_x86_64:
@@ -1046,6 +1053,8 @@ Status NativeRegisterContextNetBSD_x86_64::WriteRegister(
case lldb_dr7_x86_64:
m_dbr.dr[reg - lldb_dr0_x86_64] = reg_value.GetAsUInt64();
break;
+ default:
+ llvm_unreachable("Reading unknown/unsupported register");
}
return WriteRegisterSet(set);
@@ -1112,7 +1121,7 @@ int NativeRegisterContextNetBSD_x86_64::GetDR(int num) const {
case llvm::Triple::x86_64:
return lldb_dr0_x86_64 + num;
default:
- return -1;
+ llvm_unreachable("Unhandled target architecture.");
}
}
diff --git a/lldb/source/Plugins/Process/Utility/lldb-x86-register-enums.h b/lldb/source/Plugins/Process/Utility/lldb-x86-register-enums.h
index 35f1a4075d09..3bee9393719d 100644
--- a/lldb/source/Plugins/Process/Utility/lldb-x86-register-enums.h
+++ b/lldb/source/Plugins/Process/Utility/lldb-x86-register-enums.h
@@ -106,7 +106,7 @@ enum {
lldb_bnd1_i386,
lldb_bnd2_i386,
lldb_bnd3_i386,
- k_last_mpxr = lldb_bnd3_i386,
+ k_last_mpxr_i386 = lldb_bnd3_i386,
k_first_mpxc_i386,
lldb_bndcfgu_i386 = k_first_mpxc_i386,
More information about the lldb-commits
mailing list