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Nov 5, 2024
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[WebAssembly] Add/Reorder legacy EH tests #114363

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277 changes: 192 additions & 85 deletions llvm/test/CodeGen/WebAssembly/cfg-stackify-eh-legacy.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -205,16 +205,64 @@ unreachable: ; preds = %rethrow5
unreachable
}

; Nested loop within a catch clause
; void loop_within_catch() {
; Nested try-catches within a try
; void nested_try() {
; try {
; foo();
; } catch (...) {
; for (int i = 0; i < 50; i++)
; try {
; foo();
; } catch (...) {
; }
; } catch (...) {
; }
; }

; CHECK-LABEL: nested_try:
; CHECK: try
; CHECK: try
; CHECK: call foo
; CHECK: catch
; CHECK: call $drop=, __cxa_begin_catch
; CHECK: call __cxa_end_catch
; CHECK: end_try
; CHECK: catch
; CHECK: call $drop=, __cxa_begin_catch
; CHECK: call __cxa_end_catch
; CHECK: end_try
define void @nested_try() personality ptr @__gxx_wasm_personality_v0 {
entry:
invoke void @foo()
to label %try.cont7 unwind label %catch.dispatch

catch.dispatch: ; preds = %entry
%0 = catchswitch within none [label %catch.start] unwind label %catch.dispatch2

catch.start: ; preds = %catch.dispatch
%1 = catchpad within %0 [ptr null]
%2 = call ptr @llvm.wasm.get.exception(token %1)
%3 = call i32 @llvm.wasm.get.ehselector(token %1)
%4 = call ptr @__cxa_begin_catch(ptr %2) [ "funclet"(token %1) ]
invoke void @__cxa_end_catch() [ "funclet"(token %1) ]
to label %invoke.cont1 unwind label %catch.dispatch2

catch.dispatch2: ; preds = %catch.start, %catch.dispatch
%5 = catchswitch within none [label %catch.start3] unwind to caller

catch.start3: ; preds = %catch.dispatch2
%6 = catchpad within %5 [ptr null]
%7 = call ptr @llvm.wasm.get.exception(token %6)
%8 = call i32 @llvm.wasm.get.ehselector(token %6)
%9 = call ptr @__cxa_begin_catch(ptr %7) [ "funclet"(token %6) ]
call void @__cxa_end_catch() [ "funclet"(token %6) ]
catchret from %6 to label %try.cont7

try.cont7: ; preds = %entry, %invoke.cont1, %catch.start3
ret void

invoke.cont1: ; preds = %catch.start
catchret from %1 to label %try.cont7
}


; CHECK-LABEL: loop_within_catch:
; CHECK: try
; CHECK: call foo
Expand Down Expand Up @@ -386,7 +434,7 @@ try.cont: ; preds = %catch.start, %loop
; If 'call foo' throws a foreign exception, it will not be caught by C1, and
; should be rethrown to the caller. But after control flow linearization, it
; will instead unwind to C0, an incorrect next EH pad. We wrap the whole
; try-catch with try-delegate that rethrows an exception to the caller to fix
; try-catch with try-delegate that rethrows the exception to the caller to fix
; this.

; NOSORT-LABEL: unwind_mismatches_0:
Expand All @@ -407,7 +455,6 @@ try.cont: ; preds = %catch.start, %loop
; NOSORT: catch {{.*}} # catch[[C0]]:
; NOSORT: end_try
; NOSORT: return

define void @unwind_mismatches_0() personality ptr @__gxx_wasm_personality_v0 {
bb0:
invoke void @foo()
Expand Down Expand Up @@ -442,7 +489,7 @@ try.cont: ; preds = %catch.start1, %catc
; 'call bar' and 'call baz''s original unwind destination was the caller, but
; after control flow linearization, their unwind destination incorrectly becomes
; 'C0'. We fix this by wrapping the calls with a nested try-delegate that
; rethrows exceptions to the caller.
; rethrows the exception to the caller.

; And the return value of 'baz' should NOT be stackified because the BB is split
; during fixing unwind mismatches.
Expand All @@ -462,7 +509,6 @@ try.cont: ; preds = %catch.start1, %catc
; NOSORT: catch {{.*}} # catch[[C0:[0-9]+]]:
; NOSORT: return
; NOSORT: end_try

define void @unwind_mismatches_1() personality ptr @__gxx_wasm_personality_v0 {
bb0:
invoke void @foo()
Expand All @@ -489,7 +535,7 @@ try.cont: ; preds = %catch.start0

; The same as unwind_mismatches_0, but we have one more call 'call @foo' in bb1
; which unwinds to the caller. IN this case bb1 has two call unwind mismatches:
; 'call @foo' unwinds to the caller and 'call @bar' unwinds to catch C0.
; 'call @foo' unwinds to the caller and 'call @bar' unwinds to catch C0.

; NOSORT-LABEL: unwind_mismatches_2:
; NOSORT: try
Expand All @@ -514,7 +560,6 @@ try.cont: ; preds = %catch.start0
; NOSORT: catch {{.*}} # catch[[C0]]:
; NOSORT: end_try
; NOSORT: return

define void @unwind_mismatches_2() personality ptr @__gxx_wasm_personality_v0 {
bb0:
invoke void @foo()
Expand Down Expand Up @@ -570,7 +615,6 @@ try.cont: ; preds = %catch.start1, %catc
; NOSORT: catch {{.*}} # catch[[C0:[0-9]+]]:
; NOSORT: return
; NOSORT: end_try

define i32 @unwind_mismatches_3() personality ptr @__gxx_wasm_personality_v0 {
bb0:
invoke void @foo()
Expand All @@ -593,46 +637,6 @@ try.cont: ; preds = %catch.start0
ret i32 0
}

; Tests the case when TEE stackifies a register in RegStackify but it gets
; unstackified in fixCallUnwindMismatches in CFGStackify.

; NOSORT-LOCALS-LABEL: unstackify_when_fixing_unwind_mismatch:
define void @unstackify_when_fixing_unwind_mismatch(i32 %x) personality ptr @__gxx_wasm_personality_v0 {
bb0:
invoke void @foo()
to label %bb1 unwind label %catch.dispatch0

bb1: ; preds = %bb0
%t = add i32 %x, 4
; This %addr is used in multiple places, so tee is introduced in RegStackify,
; which stackifies the use of %addr in store instruction. A tee has two dest
; registers, the first of which is stackified and the second is not.
; But when we introduce a nested try-delegate in fixCallUnwindMismatches in
; CFGStackify, it is possible that we end up unstackifying the first dest
; register. In that case, we convert that tee into a copy.
%addr = inttoptr i32 %t to ptr
%load = load i32, ptr %addr
%call = call i32 @baz()
%add = add i32 %load, %call
store i32 %add, ptr %addr
ret void
; NOSORT-LOCALS: i32.add
; NOSORT-LOCALS-NOT: local.tee
; NOSORT-LOCALS-NEXT: local.set

catch.dispatch0: ; preds = %bb0
%0 = catchswitch within none [label %catch.start0] unwind to caller

catch.start0: ; preds = %catch.dispatch0
%1 = catchpad within %0 [ptr null]
%2 = call ptr @llvm.wasm.get.exception(token %1)
%3 = call i32 @llvm.wasm.get.ehselector(token %1)
catchret from %1 to label %try.cont

try.cont: ; preds = %catch.start0
ret void
}

; We have two call unwind unwind mismatches:
; - A may-throw instruction unwinds to an incorrect EH pad after linearizing the
; CFG, when it is supposed to unwind to another EH pad.
Expand Down Expand Up @@ -668,7 +672,6 @@ try.cont: ; preds = %catch.start0
; NOSORT: call __cxa_end_catch
; NOSORT: end_try
; NOSORT: return

define void @unwind_mismatches_4() personality ptr @__gxx_wasm_personality_v0 {
bb0:
invoke void @foo()
Expand Down Expand Up @@ -704,6 +707,135 @@ try.cont: ; preds = %catch.start1, %catc
ret void
}

; This crashed when updating EHPadStack within fixCallUniwindMismatch had a bug.
; This should not crash and try-delegate has to be created around 'call @baz',
; because the initial TRY placement for 'call @quux' was done before 'call @baz'
; because 'call @baz''s return value is stackified.

; CHECK-LABEL: unwind_mismatches_5:
; CHECK: try
; --- try-delegate starts (call unwind mismatch)
; CHECK: try
; CHECK: call $[[RET:[0-9]+]]=, baz
; CHECK: delegate 1
; --- try-delegate ends (call unwind mismatch)
; CHECK: call quux, $[[RET]]
; CHECK: catch_all
; CHECK: end_try
define void @unwind_mismatches_5() personality ptr @__gxx_wasm_personality_v0 {
entry:
%call = call i32 @baz()
invoke void @quux(i32 %call)
to label %invoke.cont unwind label %ehcleanup

ehcleanup: ; preds = %entry
%0 = cleanuppad within none []
cleanupret from %0 unwind to caller

invoke.cont: ; preds = %entry
unreachable
}

; The structure is similar to unwind_mismatches_0, where the call to 'bar''s
; original unwind destination is catch.dispatch1 but after placing markers it
; unwinds to catch.dispatch0, which we fix. This additionally has a loop before
; the real unwind destination (catch.dispatch1).

; NOSORT-LABEL: unwind_mismatches_with_loop:
; NOSORT: try
; NOSORT: try
; NOSORT: try
; NOSORT: call foo
; NOSORT: try
; NOSORT: call bar
; NOSORT: delegate 3 # label/catch{{[0-9]+}}: down to catch[[C0:[0-9]+]]
; NOSORT: catch $drop=, __cpp_exception
; NOSORT: end_try
; NOSORT: delegate 2 # label/catch{{[0-9]+}}: to caller
; NOSORT: loop
; NOSORT: call foo
; NOSORT: end_loop
; NOSORT: catch $drop=, __cpp_exception # catch[[C0]]:
; NOSORT: return
; NOSORT: end_try
define void @unwind_mismatches_with_loop() personality ptr @__gxx_wasm_personality_v0 {
bb0:
invoke void @foo()
to label %bb1 unwind label %catch.dispatch0

bb1: ; preds = %bb0
invoke void @bar()
to label %bb2 unwind label %catch.dispatch1

catch.dispatch0: ; preds = %bb0
%0 = catchswitch within none [label %catch.start0] unwind to caller

catch.start0: ; preds = %catch.dispatch0
%1 = catchpad within %0 [ptr null]
%2 = call ptr @llvm.wasm.get.exception(token %1)
%3 = call i32 @llvm.wasm.get.ehselector(token %1)
catchret from %1 to label %bb2

bb2:
invoke void @foo()
to label %bb3 unwind label %catch.dispatch1

bb3: ; preds = %bb14
br label %bb2

catch.dispatch1: ; preds = %bb1
%4 = catchswitch within none [label %catch.start1] unwind to caller

catch.start1: ; preds = %catch.dispatch1
%5 = catchpad within %4 [ptr null]
%6 = call ptr @llvm.wasm.get.exception(token %5)
%7 = call i32 @llvm.wasm.get.ehselector(token %5)
catchret from %5 to label %try.cont

try.cont: ; preds = %catch.start1, %catch.start0, %bb1
ret void
}

; Tests the case when TEE stackifies a register in RegStackify but it gets
; unstackified in fixCallUnwindMismatches in CFGStackify.

; NOSORT-LOCALS-LABEL: unstackify_when_fixing_unwind_mismatch:
define void @unstackify_when_fixing_unwind_mismatch(i32 %x) personality ptr @__gxx_wasm_personality_v0 {
bb0:
invoke void @foo()
to label %bb1 unwind label %catch.dispatch0

bb1: ; preds = %bb0
%t = add i32 %x, 4
; This %addr is used in multiple places, so tee is introduced in RegStackify,
; which stackifies the use of %addr in store instruction. A tee has two dest
; registers, the first of which is stackified and the second is not.
; But when we introduce a nested try-delegate in fixCallUnwindMismatches in
; CFGStackify, we end up unstackifying the first dest register. In that case,
; we convert that tee into a copy.
%addr = inttoptr i32 %t to ptr
%load = load i32, ptr %addr
%call = call i32 @baz()
%add = add i32 %load, %call
store i32 %add, ptr %addr
ret void
; NOSORT-LOCALS: i32.add
; NOSORT-LOCALS-NOT: local.tee
; NOSORT-LOCALS-NEXT: local.set

catch.dispatch0: ; preds = %bb0
%0 = catchswitch within none [label %catch.start0] unwind to caller

catch.start0: ; preds = %catch.dispatch0
%1 = catchpad within %0 [ptr null]
%2 = call ptr @llvm.wasm.get.exception(token %1)
%3 = call i32 @llvm.wasm.get.ehselector(token %1)
catchret from %1 to label %try.cont

try.cont: ; preds = %catch.start0
ret void
}

; In CFGSort, EH pads should be sorted as soon as it is available and
; 'Preferred' queue and should NOT be entered into 'Ready' queue unless we are
; in the middle of sorting another region that does not contain the EH pad. In
Expand Down Expand Up @@ -1004,11 +1136,13 @@ invoke.cont2: ; preds = %catch.start
; to the exception, but does not belong to the loop (because it does not have a
; path back to the loop header), and is placed after the loop latch block
; 'invoke.cont' intentionally. This tests if 'end_loop' marker is placed
; correctly not right after 'invoke.cont' part but after 'ehcleanup' part,
; correctly not right after 'invoke.cont' part but after 'ehcleanup' part.
; NOSORT-LABEL: loop_contains_exception:
; NOSORT: loop
; NOSORT: try
; NOSORT: end_try
; NOSORT: try
; NOSORT: try
; NOSORT: end_try
; NOSORT: end_try
; NOSORT: end_loop
define void @loop_contains_exception(i32 %n) personality ptr @__gxx_wasm_personality_v0 {
entry:
Expand Down Expand Up @@ -1094,33 +1228,6 @@ ehcleanup: ; preds = %if.then
cleanupret from %0 unwind to caller
}

; This crashed when updating EHPadStack within fixCallUniwindMismatch had a bug.
; This should not crash and try-delegate has to be created around 'call @baz',
; because the initial TRY placement for 'call @quux' was done before 'call @baz'
; because 'call @baz''s return value is stackified.

; CHECK-LABEL: unwind_mismatches_5:
; CHECK: try
; CHECK: try
; CHECK: call $[[RET:[0-9]+]]=, baz
; CHECK: delegate 1
; CHECK: call quux, $[[RET]]
; CHECK: catch_all
; CHECK: end_try
define void @unwind_mismatches_5() personality ptr @__gxx_wasm_personality_v0 {
entry:
%call = call i32 @baz()
invoke void @quux(i32 %call)
to label %invoke.cont unwind label %ehcleanup

ehcleanup: ; preds = %entry
%0 = cleanuppad within none []
cleanupret from %0 unwind to caller

invoke.cont: ; preds = %entry
unreachable
}

; This tests if invalidated branch destinations after fixing catch unwind
; mismatches are correctly remapped. For example, we have this code and suppose
; we need to wrap this try-catch-end in this code with a try-delegate to fix a
Expand Down Expand Up @@ -1629,8 +1736,8 @@ unreachable: ; preds = %rethrow, %entry
}

; Check if the unwind destination mismatch stats are correct
; NOSORT: 23 wasm-cfg-stackify - Number of call unwind mismatches found
; NOSORT: 4 wasm-cfg-stackify - Number of catch unwind mismatches found
; NOSORT: 24 wasm-cfg-stackify - Number of call unwind mismatches found
; NOSORT: 5 wasm-cfg-stackify - Number of catch unwind mismatches found

declare void @foo()
declare void @bar()
Expand Down
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