gollvm: fix crash on non-trivial switch case with fallthrough
The code in GenBlocks::genSwitch that handled switch case fallthrough
branches was not properly handling case statements that have internal
control flow (as opposed to being a single basic block).
Change-Id: Id0cecea2422d43cddf5e8f972a5a6786ff4ce62f
Reviewed-on: https://go-review.googlesource.com/48451
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/llvm-gofrontend/go-llvm.cpp b/llvm-gofrontend/go-llvm.cpp
index 9b0766a..e5e804c 100644
--- a/llvm-gofrontend/go-llvm.cpp
+++ b/llvm-gofrontend/go-llvm.cpp
@@ -2561,13 +2561,13 @@
// Walk statement/block
for (unsigned idx = 0; idx < ncases; ++idx) {
Bstatement *st = swst->getSwitchStmtNthStmt(idx);
- walk(st, blocks[idx]);
- if (! blocks[idx]->getTerminator()) {
+ llvm::BasicBlock *newblock = walk(st, blocks[idx]);
+ if (newblock && newblock->getTerminator() == nullptr) {
// The front end inserts a goto statement at the end for
// non-fallthrough cases. Fall through to the next case
// otherwise.
assert(idx < ncases-1);
- builder.SetInsertPoint(blocks[idx]);
+ builder.SetInsertPoint(newblock);
builder.CreateBr(blocks[idx+1]);
}
}
diff --git a/unittests/BackendCore/BackendStmtTests.cpp b/unittests/BackendCore/BackendStmtTests.cpp
index 1e54203..f127c81 100644
--- a/unittests/BackendCore/BackendStmtTests.cpp
+++ b/unittests/BackendCore/BackendStmtTests.cpp
@@ -340,12 +340,16 @@
Bstatement *cs1 = be->compound_statement(as1, goto1);
// second case
- // loc1 = 987 * loc1
+ // loc1 = loc1 < 987 ? loc1 : 987 * loc1
Bexpression *ve2 = be->var_expression(loc1, VE_lvalue, loc);
Bexpression *ve2r = be->var_expression(loc1, VE_rvalue, loc);
+ Bexpression *ve2r2 = be->var_expression(loc1, VE_rvalue, loc);
+ Bexpression *ve2r3 = be->var_expression(loc1, VE_rvalue, loc);
Bexpression *c987 = mkInt64Const(be, 987);
Bexpression *mul = be->binary_expression(OPERATOR_MULT, c987, ve2r, loc);
- Bstatement *as2 = be->assignment_statement(func, ve2, mul, loc);
+ Bexpression *cmp = be->binary_expression(OPERATOR_LE, ve2r2, c987, loc);
+ Bexpression *condex = be->conditional_expression(func, bi64t, cmp, ve2r3, mul, loc);
+ Bstatement *as2 = be->assignment_statement(func, ve2, condex, loc);
// implicit fallthrough
// third case
@@ -385,34 +389,57 @@
%param2.addr = alloca i32
%param3.addr = alloca i64*
%loc1 = alloca i64
+ %tmpv.0 = alloca i64
store i32 %param1, i32* %param1.addr
store i32 %param2, i32* %param2.addr
store i64* %param3, i64** %param3.addr
store i64 0, i64* %loc1
- %loc1.ld.2 = load i64, i64* %loc1
- switch i64 %loc1.ld.2, label %default.0 [
+ %loc1.ld.4 = load i64, i64* %loc1
+ switch i64 %loc1.ld.4, label %default.0 [
i64 1, label %case.0
i64 2, label %case.0
i64 3, label %case.1
i64 4, label %case.1
]
- case.0: ; preds = %entry, %entry
+
+ case.0: ; preds = %entry, %entry
%loc1.ld.0 = load i64, i64* %loc1
%div.0 = sdiv i64 %loc1.ld.0, 123
store i64 %div.0, i64* %loc1
br label %label.0
- case.1: ; preds = %entry, %entry
+
+ case.1: ; preds = %entry, %entry
%loc1.ld.1 = load i64, i64* %loc1
- %mul.0 = mul i64 987, %loc1.ld.1
- store i64 %mul.0, i64* %loc1
- br label %default.0
- default.0: ; preds = %entry, %case.1
+ %icmp.0 = icmp sle i64 %loc1.ld.1, 987
+ %zext.0 = zext i1 %icmp.0 to i8
+ %trunc.0 = trunc i8 %zext.0 to i1
+ br i1 %trunc.0, label %then.0, label %else.0
+
+ default.0: ; preds = %entry, %fallthrough.0
store i64 456, i64* %loc1
br label %label.0
- epilog.0: ; No predecessors!
+
+ epilog.0: ; No predecessors!
br label %label.0
- label.0: ; preds = %epilog.0, %default.0, %case.0
+
+ label.0: ; preds = %epilog.0, %default.0, %case.0
ret i64 10101
+
+ then.0: ; preds = %case.1
+ %loc1.ld.3 = load i64, i64* %loc1
+ store i64 %loc1.ld.3, i64* %tmpv.0
+ br label %fallthrough.0
+
+ fallthrough.0: ; preds = %else.0, %then.0
+ %tmpv.0.ld.0 = load i64, i64* %tmpv.0
+ store i64 %tmpv.0.ld.0, i64* %loc1
+ br label %default.0
+
+ else.0: ; preds = %case.1
+ %loc1.ld.2 = load i64, i64* %loc1
+ %mul.0 = mul i64 987, %loc1.ld.2
+ store i64 %mul.0, i64* %tmpv.0
+ br label %fallthrough.0
}
)RAW_RESULT";
