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Add additional checks for phi to prevent miscompilation.

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This commit is contained in:
Christoffer Lerno
2025-08-03 17:46:03 +02:00
parent 151a28a92a
commit 4625b457fb
2 changed files with 26 additions and 5 deletions
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27
src/compiler/llvm_codegen_expr.c
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@@ -1271,6 +1271,8 @@ static inline void llvm_emit_access_addr(GenContext *c, BEValue *be_value, Expr
void llvm_set_phi(LLVMValueRef phi, LLVMValueRef val1, LLVMBasicBlockRef block1, LLVMValueRef val2, LLVMBasicBlockRef block2)
{
ASSERT(!llvm_basic_block_is_unused(block1));
ASSERT(!llvm_basic_block_is_unused(block2));
LLVMValueRef vals[2] = { val1, val2 };
LLVMBasicBlockRef blocks[2] = { block1, block2 };
LLVMAddIncoming(phi, vals, blocks, 2);
@@ -1292,6 +1294,21 @@ void llvm_new_phi(GenContext *c, BEValue *value, const char *name, Type *type, L
val2 = LLVMBuildZExt(c->builder, val2, ret_type, "");
}
}
if (llvm_basic_block_is_unused(block1))
{
if (llvm_basic_block_is_unused(block2))
{
llvm_value_set(value, llvm_get_zero_raw(ret_type), type);
return;
}
llvm_value_set(value, val2, type);
return;
}
if (llvm_basic_block_is_unused(block2))
{
llvm_value_set(value, val1, type);
return;
}
LLVMValueRef phi = LLVMBuildPhi(c->builder, ret_type, name);
llvm_set_phi(phi, val1, block1, val2, block2);
llvm_value_set(value, phi, type);
@@ -3429,6 +3446,10 @@ static void llvm_emit_slice_comp(GenContext *c, BEValue *be_value, BEValue *lhs,
LLVMValueRef failure = LLVMConstInt(c->bool_type, want_match ? 0 : 1, false);
LLVMValueRef logic_values[3] = { success, failure, failure };
LLVMBasicBlockRef blocks[3] = { all_match_block, no_match_block, match_fail_block };
for (int i = 0; i < 3; i++)
{
ASSERT(!llvm_basic_block_is_unused(blocks[i]));
}
LLVMAddIncoming(phi, logic_values, blocks, 3);
llvm_value_set(be_value, phi, type_bool);
@@ -6666,9 +6687,9 @@ static inline void llvm_emit_builtin_access(GenContext *c, BEValue *be_value, Ex
LLVMValueRef fault_data = LLVMBuildIntToPtr(c->builder, be_value->value, c->ptr_type, "");
llvm_emit_br(c, exit_block);
llvm_emit_block(c, exit_block);
LLVMValueRef phi = LLVMBuildPhi(c->builder, c->ptr_type, "faultname");
llvm_set_phi(phi, zero.value, zero_block, fault_data, ok_block);
llvm_value_set_address_abi_aligned(c, be_value, phi, type_chars);
llvm_new_phi(c, be_value, "faultname.phi", type_chars, zero.value, zero_block, fault_data, ok_block);
llvm_value_set_address_abi_aligned(c, be_value, be_value->value, type_chars);
return;
}
case ACCESS_ENUMNAME: