[lld][COFF] Remove incorrect flag from EHcont table

Fixes EHCont implementation in LLD. Closes #64570

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D157623

(cherry picked from commit e335c78ec2848e24b10e32e015a84347c69c8130)

diff --git a/lld/COFF/Writer.cpp b/lld/COFF/Writer.cpp
index 85568a1..c9b6318 100644 (file)
--- a/lld/COFF/Writer.cpp
+++ b/lld/COFF/Writer.cpp
@@ -1796,7 +1796,7 @@ void Writer::createGuardCFTables() {
   // Add the ehcont target table unless the user told us not to.
   if (config->guardCF & GuardCFLevel::EHCont)
     maybeAddRVATable(std::move(ehContTargets), "__guard_eh_cont_table",
-                     "__guard_eh_cont_count", true);
+                     "__guard_eh_cont_count");
 
   // Set __guard_flags, which will be used in the load config to indicate that
   // /guard:cf was enabled.

diff --git a/lld/test/COFF/guard-ehcont.s b/lld/test/COFF/guard-ehcont.s
index f040a62..7380768 100644 (file)
--- a/lld/test/COFF/guard-ehcont.s
+++ b/lld/test/COFF/guard-ehcont.s
@@ -10,7 +10,7 @@
 # CHECK:   GuardCFCheckFunction: 0x0
 # CHECK:   GuardCFCheckDispatch: 0x0
 # CHECK:   GuardCFFunctionTable: 0x14000{{.*}}
-# CHECK:   GuardCFFunctionCount: 4
+# CHECK:   GuardCFFunctionCount: 1
 # CHECK:   GuardFlags [ (0x400500)
 # CHECK:     CF_FUNCTION_TABLE_PRESENT (0x400)
 # CHECK:     CF_INSTRUMENTED (0x100)
@@ -19,25 +19,13 @@
 # CHECK:   GuardAddressTakenIatEntryTable: 0x0
 # CHECK:   GuardAddressTakenIatEntryCount: 0
 # CHECK:   GuardEHContinuationTable: 0x14000{{.*}}
-# CHECK:   GuardEHContinuationCount: 1
+# CHECK:   GuardEHContinuationCount: 2
 # CHECK: ]
 # CHECK:      GuardEHContTable [
 # CHECK-NEXT:   0x14000{{.*}}
+# CHECK-NEXT:   0x14000{{.*}}
 # CHECK-NEXT: ]
 
-
-# This assembly is reduced from C code like:
-# int main()
-# {
-#   try {
-#     throw 3;
-#   }
-#   catch (int e) {
-#     return e != 3;
-#   }
-#   return 2;
-# }
-
 # We need @feat.00 to have 0x4000 to indicate /guard:ehcont.
         .def     @feat.00;
         .scl    3;
@@ -48,168 +36,50 @@
         .def     main; .scl    2; .type   32; .endef
         .globl main                            # -- Begin function main
         .p2align       4, 0x90
-main:                                   # @main
-.Lfunc_begin0:
+main:
 .seh_proc main
-.intel_syntax
-        .seh_handler __CxxFrameHandler3, @unwind, @except
-# %bb.0:                                # %entry
-        push   rbp
-        .seh_pushreg rbp
-        sub    rsp, 64
-        .seh_stackalloc 64
-        lea    rbp, [rsp + 64]
-        .seh_setframe rbp, 64
-        .seh_endprologue
-        mov    qword ptr [rbp - 16], -2
-        mov    dword ptr [rbp - 20], 0
-        mov    dword ptr [rbp - 24], 3
-.Ltmp0:
-        lea    rdx, [rip + _TI1H]
-        lea    rcx, [rbp - 24]
-        call   _CxxThrowException
-.Ltmp1:
-        jmp    .LBB0_3
-.LBB0_2:                                # Block address taken
-                                        # %catchret.dest
-$ehgcr_0_2:
-        mov    eax, dword ptr [rbp - 20]
-        add    rsp, 64
-        pop    rbp
-        ret
-.LBB0_3:                                # %unreachable
-        int3
-        .seh_handlerdata
-        .long  ($cppxdata$main)@IMGREL
-        .text
-        .seh_endproc
-        .def    "?catch$1@?0?main@4HA";
-        .scl   3;
-        .type  32;
-        .endef
-        .p2align       4, 0x90
-"?catch$1@?0?main@4HA":
-.seh_proc "?catch$1@?0?main@4HA"
-        .seh_handler __CxxFrameHandler3, @unwind, @except
-.LBB0_1:                                # %catch
-        mov    qword ptr [rsp + 16], rdx
-        push   rbp
-        .seh_pushreg rbp
-        sub    rsp, 32
-        .seh_stackalloc 32
-        lea    rbp, [rdx + 64]
-        .seh_endprologue
-        mov    eax, dword ptr [rbp - 4]
-        sub    eax, 3
-        setne  al
-        movzx  eax, al
-        mov    dword ptr [rbp - 20], eax
-        lea    rax, [rip + .LBB0_2]
-        add    rsp, 32
-        pop    rbp
-        ret                                     # CATCHRET
-        .def     free; .scl    2; .type   32; .endef
-        .globl  free
-free:
-        ret
-        .def     __CxxFrameHandler3; .scl    2; .type   32; .endef
-        .globl  __CxxFrameHandler3
-__CxxFrameHandler3:
-        ret
-        .def     _CxxThrowException; .scl    2; .type   32; .endef
-        .globl  _CxxThrowException
-_CxxThrowException:
-        ret
-.Lfunc_end0:
+        .seh_handler __C_specific_handler, @unwind, @except
         .seh_handlerdata
-        .long  ($cppxdata$main)@IMGREL
+        .long 2
+        .long (seh_begin)@IMGREL
+        .long (seh_end)@IMGREL
+        .long 1
+        .long (seh_except)@IMGREL
+        .long (seh2_begin)@IMGREL
+        .long (seh2_end)@IMGREL
+        .long 1
+        .long (seh2_except)@IMGREL
         .text
-        .seh_endproc
-        .section       .xdata,"dr"
-        .p2align       2
-$cppxdata$main:
-        .long  429065506                       # MagicNumber
-        .long  2                               # MaxState
-        .long  ($stateUnwindMap$main)@IMGREL   # UnwindMap
-        .long  1                               # NumTryBlocks
-        .long  ($tryMap$main)@IMGREL           # TryBlockMap
-        .long  4                               # IPMapEntries
-        .long  ($ip2state$main)@IMGREL         # IPToStateXData
-        .long  48                              # UnwindHelp
-        .long  0                               # ESTypeList
-        .long  1                               # EHFlags
-$stateUnwindMap$main:
-        .long  -1                              # ToState
-        .long  0                               # Action
-        .long  -1                              # ToState
-        .long  0                               # Action
-$tryMap$main:
-        .long  0                               # TryLow
-        .long  0                               # TryHigh
-        .long  1                               # CatchHigh
-        .long  1                               # NumCatches
-        .long  ($handlerMap$0$main)@IMGREL     # HandlerArray
-$handlerMap$0$main:
-        .long  0                               # Adjectives
-        .long  "??_R0H@8"@IMGREL               # Type
-        .long  60                              # CatchObjOffset
-        .long  "?catch$1@?0?main@4HA"@IMGREL   # Handler
-        .long  56                              # ParentFrameOffset
-$ip2state$main:
-        .long  .Lfunc_begin0@IMGREL            # IP
-        .long  -1                              # ToState
-        .long  .Ltmp0@IMGREL+1                 # IP
-        .long  0                               # ToState
-        .long  .Ltmp1@IMGREL+1                 # IP
-        .long  -1                              # ToState
-        .long  "?catch$1@?0?main@4HA"@IMGREL   # IP
-        .long  1                               # ToState
-        .text
-                                        # -- End function
-        .section       .data,"dw",discard,"??_R0H@8"
-        .globl "??_R0H@8"                      # @"??_R0H@8"
-        .p2align       4
-"??_R0H@8":
-        .quad  0
-        .quad  0
-        .asciz ".H"
-        .zero  5
+    seh_begin:
+        nop
+        int3
+        nop
+    seh_end:
+        nop
+    seh_except:
+        nop
 
-        .section       .xdata,"dr",discard,"_CT??_R0H@84"
-        .globl "_CT??_R0H@84"                  # @"_CT??_R0H@84"
-        .p2align       4
-"_CT??_R0H@84":
-        .long  1                               # 0x1
-        .long  "??_R0H@8"@IMGREL
-        .long  0                               # 0x0
-        .long  4294967295                      # 0xffffffff
-        .long  0                               # 0x0
-        .long  4                               # 0x4
-        .long  0                               # 0x0
+    seh2_begin:
+        nop
+        int3
+        nop
+    seh2_end:
+        nop
+    seh2_except:
+        nop
+
+        xor %eax, %eax
+        ret
+.seh_endproc
 
-        .section       .xdata,"dr",discard,_CTA1H
-        .globl _CTA1H                          # @_CTA1H
-        .p2align       3
-_CTA1H:
-        .long  1                               # 0x1
-        .long  "_CT??_R0H@84"@IMGREL
+__C_specific_handler:
+        ret
 
-        .section       .xdata,"dr",discard,_TI1H
-        .globl _TI1H                           # @_TI1H
-        .p2align       3
-_TI1H:
-        .long  0                               # 0x0
-        .long  0                               # 0x0
-        .long  0                               # 0x0
-        .long  _CTA1H@IMGREL
+.section       .gehcont$y,"dr"
+.symidx        seh_except
+.symidx        seh2_except
 
-        .section       .gehcont$y,"dr"
-        .symidx        $ehgcr_0_2
-        .addrsig_sym _CxxThrowException
-        .addrsig_sym __CxxFrameHandler3
-        .addrsig_sym "??_R0H@8"
-        .addrsig_sym __ImageBase
-        .section  .rdata,"dr"
+.section  .rdata,"dr"
 .globl _load_config_used
 _load_config_used:
         .long 312

diff --git a/llvm/tools/llvm-readobj/COFFDumper.cpp b/llvm/tools/llvm-readobj/COFFDumper.cpp
index 0a5073d..4caa1c7 100644 (file)
--- a/llvm/tools/llvm-readobj/COFFDumper.cpp
+++ b/llvm/tools/llvm-readobj/COFFDumper.cpp
@@ -940,36 +940,34 @@ void COFFDumper::printCOFFLoadConfig() {
       OS << " flags " << utohexstr(Flags);
   };
 
+  // The stride gives the number of extra bytes in addition to the 4-byte
+  // RVA of each entry in the table. As of writing only a 1-byte extra flag
+  // has been defined.
+  uint32_t Stride = Tables.GuardFlags >> 28;
+  PrintExtraCB PrintExtra = Stride == 1 ? PrintGuardFlags : nullptr;
+
   if (Tables.GuardFidTableVA) {
     ListScope LS(W, "GuardFidTable");
-    if (uint32_t Size =
-            Tables.GuardFlags &
-            uint32_t(COFF::GuardFlags::CF_FUNCTION_TABLE_SIZE_MASK)) {
-      // The size mask gives the number of extra bytes in addition to the 4-byte
-      // RVA of each entry in the table. As of writing only a 1-byte extra flag
-      // has been defined.
-      Size = (Size >> 28) + 4;
-      printRVATable(Tables.GuardFidTableVA, Tables.GuardFidTableCount, Size,
-                    PrintGuardFlags);
-    } else {
-      printRVATable(Tables.GuardFidTableVA, Tables.GuardFidTableCount, 4);
-    }
+    printRVATable(Tables.GuardFidTableVA, Tables.GuardFidTableCount,
+                  4 + Stride, PrintExtra);
   }
 
   if (Tables.GuardIatTableVA) {
     ListScope LS(W, "GuardIatTable");
-    printRVATable(Tables.GuardIatTableVA, Tables.GuardIatTableCount, 4);
+    printRVATable(Tables.GuardIatTableVA, Tables.GuardIatTableCount,
+                  4 + Stride, PrintExtra);
   }
 
   if (Tables.GuardLJmpTableVA) {
     ListScope LS(W, "GuardLJmpTable");
-    printRVATable(Tables.GuardLJmpTableVA, Tables.GuardLJmpTableCount, 4);
+    printRVATable(Tables.GuardLJmpTableVA, Tables.GuardLJmpTableCount,
+                  4 + Stride, PrintExtra);
   }
 
   if (Tables.GuardEHContTableVA) {
     ListScope LS(W, "GuardEHContTable");
-    printRVATable(Tables.GuardEHContTableVA, Tables.GuardEHContTableCount, 5,
-                  PrintGuardFlags);
+    printRVATable(Tables.GuardEHContTableVA, Tables.GuardEHContTableCount,
+                  4 + Stride, PrintExtra);
   }
 }