Merge branch 'junghee/lsda-boundary-sym' into 'main'

Add boundary_sym_expr for lsda entry with symbol pointing to the end of section

Closes #599

See merge request rewriting/ddisasm!1192

CHANGELOG.md

@@ -18,6 +18,7 @@
   Heuristic weights can now be modified by providing user hints.
 * Generate GOT, PAGE and GOT, OFST symbolic expression attributes for split
   .got loads on MIPS.
+* Correct symbol_minus_symbol in lsda entries with a reference to the end of `.gcc_except_table`: add `boundary_sym_expr` for such reference
 
 # 1.8.0
 

examples/ex_exceptions4/Makefile

@@ -0,0 +1,20 @@
+CXX="g++"
+EXEC=
+
+all: ex.cpp
+	# NOTE: `-T linker-script.ld`
+	# This is to place .gcc_except_table *before* .note.gnu.build-id
+	# so that the reference label for the end of the section is aligned
+	# with the adjacent section.
+	#
+	# With this example, if a boundary_sym_expr is not correctly created
+	# for symbol_minus_symbol, the assembler will fail with
+	# "Error: invalid operands for '-'"
+	$(CXX) ex.cpp $(CXXFLAGS) -T linker-script.ld -o ex
+	@ $(EXEC) ./ex > out.txt
+clean:
+	rm -f ex out.txt
+	rm -fr ex.unstripped *.s *.old*  dl_files *.gtirb
+check:
+	@ $(EXEC) ./ex >/tmp/res.txt
+	@ diff out.txt /tmp/res.txt && echo TEST OK

examples/ex_exceptions4/ex.cpp

@@ -0,0 +1,16 @@
+#include <exception>
+#include <iostream>
+
+int main()
+{
+    try
+    {
+        throw std::logic_error("This is a logic error");
+    }
+    catch(std::exception& e)
+    {
+        std::cout << e.what() << std::endl;
+    }
+
+    return 0;
+}

examples/ex_exceptions4/linker-script.ld

@@ -0,0 +1,4 @@
+SECTIONS {
+  .gcc_except_table : { *(.gcc_except_table) }
+}
+INSERT BEFORE .note.gnu.build-id;

src/datalog/binary/elf/exceptions.dl

@@ -172,9 +172,24 @@ labeled_ea(Personality):-
 /////////////////////////////////////////////////////////////////////////////////
 // Symbols in lsda
 
+/**
+Same as `symbol_minus_symbol`: this is to avoid cyclic aggregation by
+`boundary_sym_expr` using `symbol_minus_symbol`.
+*/
+.decl lsda_symbol_minus_symbol(EA:address,Size:unsigned,Symbol1:address,Symbol2:address,Scale:unsigned,Offset:number)
+
+symbol_minus_symbol(EA,Size,Symbol1,Symbol2,Scale,Offset):-
+    lsda_symbol_minus_symbol(EA,Size,Symbol1,Symbol2,Scale,Offset).
+
+// If the second address is the end of the section, create `boundary_sym_expr`
+// for the address.
+boundary_sym_expr(EA, Dest):-
+    lsda_symbol_minus_symbol(EA,_,_,Dest,_,_),
+    loaded_section(_,Dest,_).
+
 // type table pointer
 symbol_special_encoding(TypeTablePointerLocation,"uleb128"),
-symbol_minus_symbol(TypeTablePointerLocation,Size,CallsiteTablePointerLoc-1,LsdaTypeTableAddress,1,0):-
+lsda_symbol_minus_symbol(TypeTablePointerLocation,Size,CallsiteTablePointerLoc-1,LsdaTypeTableAddress,1,0):-
     lsda_pointer_locations(Lsda,TypeTablePointerLocation,CallsiteTablePointerLoc),
     lsda(Lsda,_,_,_,LsdaTypeTableAddress, _, _),
     LsdaTypeTableAddress != 0,
@@ -183,7 +198,7 @@ symbol_minus_symbol(TypeTablePointerLocation,Size,CallsiteTablePointerLoc-1,Lsda
 
 //callsite table size
 symbol_special_encoding(CallsiteTablePointerLoc,"uleb128"),
-symbol_minus_symbol(CallsiteTablePointerLoc,Size,CallSiteTable_address,CallSiteTable_address+CallSiteTableLength,1,0):-
+lsda_symbol_minus_symbol(CallsiteTablePointerLoc,Size,CallSiteTable_address,CallSiteTable_address+CallSiteTableLength,1,0):-
     lsda_pointer_locations(Lsda,_,CallsiteTablePointerLoc),
     lsda(Lsda,CallSiteTable_address,_,CallSiteTableLength,_, _, _),
     Size = CallSiteTable_address - CallsiteTablePointerLoc,
@@ -202,23 +217,23 @@ symbol_special_encoding(EA_landingPad,EncodingName):-
 
 
 //region beginning
-symbol_minus_symbol(EA_start,Size,LandingPadBaseAddress,StartRegion,1,0):-
+lsda_symbol_minus_symbol(EA_start,Size,LandingPadBaseAddress,StartRegion,1,0):-
     lsda_callsite(CallSiteTable_address, EA_start, StartRegion,EA_end,_,_,_,_),
     lsda(_,CallSiteTable_address,_,_,_,_,LandingPadBaseAddress),
     Size = EA_end-EA_start,
     Size > 0.
 
 //region end
 boundary_sym_expr(EA_end,EndRegion),
-symbol_minus_symbol(EA_end,Size,StartRegion,EndRegion,1,0):-
+lsda_symbol_minus_symbol(EA_end,Size,StartRegion,EndRegion,1,0):-
     lsda_callsite(_, _, StartRegion,EA_end,EndRegion,EA_landingPad,_,_),
     Size = EA_landingPad-EA_end,
     Size > 0,
     // Boundary is at the end of the block preceding the EndRegion label.
     block_boundaries(_,_,EndRegion).
 
 //landing pad
-symbol_minus_symbol(EA_landingPad,Size,LandingPadBaseAddress,LandingPad,1,0):-
+lsda_symbol_minus_symbol(EA_landingPad,Size,LandingPadBaseAddress,LandingPad,1,0):-
     lsda_callsite(CallSiteTable_address, _, _,_,_,EA_landingPad,LandingPad,EA_endLandingPad),
     lsda(_,CallSiteTable_address,_,_,_,_,LandingPadBaseAddress),
     LandingPad != 0,
@@ -236,7 +251,7 @@ symbolic_data(EAType,EncodingSize,Type):-
     EAType=LsdaTypeTableAddress-(EncodingSize*(Index+1)),
     Type != 0.
 
-symbol_minus_symbol(EAType,EncodingSize,EAType,Type,1,0):-
+lsda_symbol_minus_symbol(EAType,EncodingSize,EAType,Type,1,0):-
     lsda_type_entry(LsdaTypeTableAddress, Index,Type),
     lsda(_,_,_,_,LsdaTypeTableAddress, TypeTableEncoding, _),
     TypeTableEncoding band 0xF = Encoding,

tests/linux-elf-x64.yaml

@@ -168,6 +168,9 @@ tests:
   - name: ex_exceptions3
     <<: *default-cpp
 
+  - name: ex_exceptions4
+    <<: *default-cpp
+
   - name: ex_false_pointer_array
     <<: *default
 
@@ -375,6 +378,10 @@ tests:
     <<: *default-cpp
     <<: *test-strip-default
 
+  - name: ex_exceptions4
+    <<: *default-cpp
+    <<: *test-strip-default
+
   - name: ex_false_pointer_array
     <<: *default
     <<: *test-strip-default
@@ -664,6 +671,10 @@ tests:
   # - name: ex_exceptions3
   #   <<: *cpp-object
 
+  # TODO:
+  # - name: ex_exceptions4
+  #   <<: *cpp-object
+
   - name: ex_false_pointer_array
     <<: *c-object
 

tests/linux-elf-x86.yaml

@@ -126,6 +126,9 @@ tests:
   - name: ex_exceptions3
     <<: *default-cpp
 
+  - name: ex_exceptions4
+    <<: *default-cpp
+
   - name: ex_false_pointer_array
     <<: *default
 
@@ -212,6 +215,9 @@ tests:
   - name: ex_exceptions3
     <<: *position-independent-cpp
 
+  - name: ex_exceptions4
+    <<: *position-independent-cpp
+
   - name: ex_false_pointer_array
     <<: *position-independent
     test: