Skip to content

C++: Generate SEH edges for pointer dereference loads/stores in __try blocks #19775

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
jketema merged 4 commits into from
Jun 16, 2025
Merged

C++: Generate SEH edges for pointer dereference loads/stores in __try blocks #19775

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
67d623f
C++: Add `__try` with load test case
jketema Jun 13, 2025
3eb768c
C++: Generate SEH edges for pointer dereference stores in `__try` blocks
jketema Jun 13, 2025
9d6a1a9
C++: Generate SEH edges for pointer dereference loads in `__try` blocks
jketema Jun 13, 2025
4228828
C++: Address review comments
jketema Jun 16, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 8 additions & 1 deletion cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedExpr.qll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -400,7 +400,14 @@ class TranslatedLoad extends TranslatedValueCategoryAdjustment, TTranslatedLoad

override Instruction getInstructionSuccessorInternal(InstructionTag tag, EdgeKind kind) {
tag = LoadTag() and
result = this.getParent().getChildSuccessor(this, kind)
(
result = this.getParent().getChildSuccessor(this, kind)
or
expr instanceof PointerDereferenceExpr and
kind instanceof SehExceptionEdge and
exists(MicrosoftTryStmt tryStmt | tryStmt.getStmt() = expr.getEnclosingStmt().getParent*()) and
Copy link
Copy Markdown
Contributor

@MathiasVP MathiasVP Jun 16, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We should probably lift this out to a predicate at this point so that we don't accidentally write the wrong predicate you fixed in 1b2813d

Copy link
Copy Markdown
Contributor Author

@jketema jketema Jun 16, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I've unified the two in TranslatedExpr.qll.

result = this.getParent().getExceptionSuccessorInstruction(any(GotoEdge e))
)
}

override Instruction getChildSuccessorInternal(TranslatedElement child, EdgeKind kind) {
Expand Down
85 changes: 48 additions & 37 deletions cpp/ql/test/library-tests/ir/ir/aliased_ir.expected
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -39290,70 +39290,81 @@ try_except.c:
# 59| r59_1(glval<int *>) = VariableAddress[b] :
# 59| r59_2(int *) = Load[b] : &:r59_1, m56_6
# 59| r59_3(int) = Load[?] : &:r59_2, ~m56_8
# 59| r59_4(glval<int>) = VariableAddress[x] :
# 59| m59_5(int) = Store[x] : &:r59_4, r59_3
# 60| r60_1(glval<int>) = VariableAddress[x] :
# 60| r60_2(int) = Load[x] : &:r60_1, m59_5
# 60| r60_3(glval<int *>) = VariableAddress[c] :
# 60| r60_4(int *) = Load[c] : &:r60_3, m56_10
# 60| r60_5(glval<int>) = CopyValue : r60_4
# 60| m60_6(int) = Store[?] : &:r60_5, r60_2
# 60| m60_7(unknown) = Chi : total:m56_12, partial:m60_6
#-----| Goto -> Block 1
#-----| SEH Exception -> Block 4
#-----| SEH Exception -> Block 6

# 59| Block 1
# 59| r59_4(glval<int>) = VariableAddress[x] :
# 59| m59_5(int) = Store[x] : &:r59_4, r59_3
# 60| r60_1(glval<int>) = VariableAddress[x] :
# 60| r60_2(int) = Load[x] : &:r60_1, m59_5
# 60| r60_3(glval<int *>) = VariableAddress[c] :
# 60| r60_4(int *) = Load[c] : &:r60_3, m56_10
# 60| r60_5(glval<int>) = CopyValue : r60_4
# 60| m60_6(int) = Store[?] : &:r60_5, r60_2
# 60| m60_7(unknown) = Chi : total:m56_12, partial:m60_6
#-----| Goto -> Block 2
#-----| SEH Exception -> Block 6

# 61| Block 1
# 61| Block 2
# 61| r61_1(glval<int>) = VariableAddress[y] :
# 61| r61_2(glval<int *>) = VariableAddress[d] :
# 61| r61_3(int *) = Load[d] : &:r61_2, m56_14
# 61| r61_4(int) = Load[?] : &:r61_3, ~m56_16
# 61| m61_5(int) = Store[y] : &:r61_1, r61_4
#-----| Goto -> Block 6
#-----| Goto -> Block 3
#-----| SEH Exception -> Block 6

# 61| Block 3
# 61| m61_5(int) = Store[y] : &:r61_1, r61_4
#-----| Goto -> Block 8

# 63| Block 2
# 63| Block 4
# 63| r63_1(int) = Constant[0] :
# 63| r63_2(bool) = CompareEQ : r63_7, r63_1
# 63| r63_2(bool) = CompareEQ : r63_9, r63_1
# 63| v63_3(void) = ConditionalBranch : r63_2
#-----| False -> Block 3
#-----| True -> Block 7
#-----| False -> Block 5
#-----| True -> Block 9

# 63| Block 3
# 63| Block 5
# 63| r63_4(int) = Constant[1] :
# 63| r63_5(bool) = CompareEQ : r63_7, r63_4
# 63| r63_5(bool) = CompareEQ : r63_9, r63_4
# 63| v63_6(void) = ConditionalBranch : r63_5
#-----| False -> Block 7
#-----| True -> Block 5

# 63| Block 4
# 63| r63_7(int) = Constant[1] :
# 63| r63_8(int) = Constant[-1] :
# 63| r63_9(bool) = CompareEQ : r63_7, r63_8
# 63| v63_10(void) = ConditionalBranch : r63_9
#-----| False -> Block 2
#-----| False -> Block 9
#-----| True -> Block 7

# 64| Block 5
# 63| Block 6
# 63| m63_7(unknown) = Phi : from 0:m56_12, from 1:m60_7, from 2:m60_7
# 63| m63_8(int) = Phi : from 0:m57_3, from 1:m59_5, from 2:m59_5
# 63| r63_9(int) = Constant[1] :
# 63| r63_10(int) = Constant[-1] :
# 63| r63_11(bool) = CompareEQ : r63_9, r63_10
# 63| v63_12(void) = ConditionalBranch : r63_11
#-----| False -> Block 4
#-----| True -> Block 9

# 64| Block 7
# 64| r64_1(glval<unknown>) = FunctionAddress[sink] :
# 64| r64_2(glval<int>) = VariableAddress[x] :
# 64| r64_3(int) = Load[x] : &:r64_2, m59_5
# 64| r64_3(int) = Load[x] : &:r64_2, m63_8
# 64| v64_4(void) = Call[sink] : func:r64_1, 0:r64_3
# 64| m64_5(unknown) = ^CallSideEffect : ~m56_4
# 64| m64_6(unknown) = Chi : total:m56_4, partial:m64_5
#-----| Goto -> Block 6
#-----| Goto -> Block 8

# 66| Block 6
# 66| m66_1(unknown) = Phi : from 1:~m56_4, from 5:~m64_6
# 66| v66_2(void) = NoOp :
# 66| Block 8
# 66| m66_1(unknown) = Phi : from 3:m60_7, from 7:m63_7
# 66| m66_2(unknown) = Phi : from 3:~m56_4, from 7:~m64_6
# 66| v66_3(void) = NoOp :
# 56| v56_25(void) = ReturnIndirection[b] : &:r56_7, m56_8
# 56| v56_26(void) = ReturnIndirection[c] : &:r56_11, m60_7
# 56| v56_26(void) = ReturnIndirection[c] : &:r56_11, m66_1
# 56| v56_27(void) = ReturnIndirection[d] : &:r56_15, m56_16
# 56| v56_28(void) = ReturnIndirection[e] : &:r56_19, m56_20
# 56| v56_29(void) = ReturnIndirection[f] : &:r56_23, m56_24
# 56| v56_30(void) = ReturnVoid :
# 56| v56_31(void) = AliasedUse : ~m66_1
# 56| v56_31(void) = AliasedUse : ~m66_2
# 56| v56_32(void) = ExitFunction :

# 56| Block 7
# 56| Block 9
# 56| v56_33(void) = Unreached :

try_except.cpp:
Expand Down
50 changes: 29 additions & 21 deletions cpp/ql/test/library-tests/ir/ir/raw_ir.expected
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -37564,16 +37564,8 @@ try_except.c:
# 59| r59_1(glval<int *>) = VariableAddress[b] :
# 59| r59_2(int *) = Load[b] : &:r59_1, ~m?
# 59| r59_3(int) = Load[?] : &:r59_2, ~m?
# 59| r59_4(glval<int>) = VariableAddress[x] :
# 59| mu59_5(int) = Store[x] : &:r59_4, r59_3
# 60| r60_1(glval<int>) = VariableAddress[x] :
# 60| r60_2(int) = Load[x] : &:r60_1, ~m?
# 60| r60_3(glval<int *>) = VariableAddress[c] :
# 60| r60_4(int *) = Load[c] : &:r60_3, ~m?
# 60| r60_5(glval<int>) = CopyValue : r60_4
# 60| mu60_6(int) = Store[?] : &:r60_5, r60_2
#-----| Goto -> Block 3
#-----| SEH Exception -> Block 6
#-----| SEH Exception -> Block 8

# 56| Block 1
# 56| v56_24(void) = AliasedUse : ~m?
Expand All @@ -37583,44 +37575,60 @@ try_except.c:
# 56| v56_26(void) = Unwind :
#-----| Goto -> Block 1

# 61| Block 3
# 59| Block 3
# 59| r59_4(glval<int>) = VariableAddress[x] :
# 59| mu59_5(int) = Store[x] : &:r59_4, r59_3
# 60| r60_1(glval<int>) = VariableAddress[x] :
# 60| r60_2(int) = Load[x] : &:r60_1, ~m?
# 60| r60_3(glval<int *>) = VariableAddress[c] :
# 60| r60_4(int *) = Load[c] : &:r60_3, ~m?
# 60| r60_5(glval<int>) = CopyValue : r60_4
# 60| mu60_6(int) = Store[?] : &:r60_5, r60_2
#-----| Goto -> Block 4
#-----| SEH Exception -> Block 8

# 61| Block 4
# 61| r61_1(glval<int>) = VariableAddress[y] :
# 61| r61_2(glval<int *>) = VariableAddress[d] :
# 61| r61_3(int *) = Load[d] : &:r61_2, ~m?
# 61| r61_4(int) = Load[?] : &:r61_3, ~m?
# 61| mu61_5(int) = Store[y] : &:r61_1, r61_4
#-----| Goto -> Block 8
#-----| Goto -> Block 5
#-----| SEH Exception -> Block 8

# 61| Block 5
# 61| mu61_5(int) = Store[y] : &:r61_1, r61_4
#-----| Goto -> Block 10

# 63| Block 4
# 63| Block 6
# 63| r63_1(int) = Constant[0] :
# 63| r63_2(bool) = CompareEQ : r63_7, r63_1
# 63| v63_3(void) = ConditionalBranch : r63_2
#-----| False -> Block 5
#-----| False -> Block 7
#-----| True -> Block 2

# 63| Block 5
# 63| Block 7
# 63| r63_4(int) = Constant[1] :
# 63| r63_5(bool) = CompareEQ : r63_7, r63_4
# 63| v63_6(void) = ConditionalBranch : r63_5
#-----| True -> Block 7
#-----| True -> Block 9

# 63| Block 6
# 63| Block 8
# 63| r63_7(int) = Constant[1] :
# 63| r63_8(int) = Constant[-1] :
# 63| r63_9(bool) = CompareEQ : r63_7, r63_8
# 63| v63_10(void) = ConditionalBranch : r63_9
#-----| False -> Block 4
#-----| False -> Block 6
#-----| True -> Block 2

# 64| Block 7
# 64| Block 9
# 64| r64_1(glval<unknown>) = FunctionAddress[sink] :
# 64| r64_2(glval<int>) = VariableAddress[x] :
# 64| r64_3(int) = Load[x] : &:r64_2, ~m?
# 64| v64_4(void) = Call[sink] : func:r64_1, 0:r64_3
# 64| mu64_5(unknown) = ^CallSideEffect : ~m?
#-----| Goto -> Block 8
#-----| Goto -> Block 10

# 66| Block 8
# 66| Block 10
# 66| v66_1(void) = NoOp :
# 56| v56_27(void) = ReturnIndirection[b] : &:r56_6, ~m?
# 56| v56_28(void) = ReturnIndirection[c] : &:r56_10, ~m?
Expand Down