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[v2,05/27] llvm: fix translation of PSEUDO_VALs into a ValueRefs

Message ID 20170311090706.17171-6-luc.vanoostenryck@gmail.com (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Luc Van Oostenryck March 11, 2017, 9:06 a.m. UTC
In sparse-llvm there is the assumption that a PSEUDO_VAL is always
of integer type. But this is not always the case: constant pointers,
like NULL, are also of the PSEUDO_VAL kind.

Fix this by adding a helper 'val_to_value()' and using the
instruction's type where this pseudo is used as the type of the value.

Note: while this patch improve the situation, like for example for the
test cases added here, it's still not correct because now we're making
the assumption that 'insn->type' is the type we need for the pseudo.
This is often true, but certainly not always.
For example this is not true for:
- OP_STORE/OP_LOAD's insn->src
- OP_SET{EQ,...}'s   insn->src[12]
- probably some  others ones
- in general, obviously, for any instructions where the target has
  a different type than the operands.

Reported-by: Dibyendu Majumdar <mobile@majumdar.org.uk>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 sparse-llvm.c             | 26 +++++++++++++++++++++++++-
 validation/backend/null.c | 24 ++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 validation/backend/null.c
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Patch

diff --git a/sparse-llvm.c b/sparse-llvm.c
index 9f362b3ed..d48b3b20a 100644
--- a/sparse-llvm.c
+++ b/sparse-llvm.c
@@ -303,6 +303,30 @@  static void pseudo_name(pseudo_t pseudo, char *buf)
 	}
 }
 
+static LLVMValueRef val_to_value(struct function *fn, unsigned long long val, struct symbol *ctype)
+{
+	LLVMTypeRef dtype;
+	LLVMTypeRef itype;
+	LLVMValueRef result;
+
+	assert(ctype);
+	dtype = symbol_type(fn->module, ctype);
+	switch (LLVMGetTypeKind(dtype)) {
+	case LLVMPointerTypeKind:
+		itype = LLVMIntType(bits_in_pointer);
+		result = LLVMConstInt(itype, val, 1);
+		result = LLVMConstIntToPtr(result, dtype);
+		break;
+	case LLVMIntegerTypeKind:
+		result = LLVMConstInt(dtype, val, 1);
+		break;
+	default:
+		assert(0);
+	}
+
+	return result;
+}
+
 static LLVMValueRef pseudo_to_value(struct function *fn, struct instruction *insn, pseudo_t pseudo)
 {
 	LLVMValueRef result = NULL;
@@ -360,7 +384,7 @@  static LLVMValueRef pseudo_to_value(struct function *fn, struct instruction *ins
 		break;
 	}
 	case PSEUDO_VAL:
-		result = LLVMConstInt(insn_symbol_type(fn->module, insn), pseudo->value, 1);
+		result = val_to_value(fn, pseudo->value, insn->type);
 		break;
 	case PSEUDO_ARG: {
 		result = LLVMGetParam(fn->fn, pseudo->nr - 1);
diff --git a/validation/backend/null.c b/validation/backend/null.c
new file mode 100644
index 000000000..5c595c70b
--- /dev/null
+++ b/validation/backend/null.c
@@ -0,0 +1,24 @@ 
+extern int *ip[];
+
+void foo(void);
+void foo(void)
+{
+	ip[0] = (void *)0L;
+	ip[1] = (int *)0L;
+	ip[2] = (void *)0;
+	ip[3] = (int *)0;
+	ip[4] = (void *)(long)0;
+	ip[5] = (int *)(long)0;
+	ip[6] = (void *)123;
+	ip[7] = (int *)123;
+	ip[8] = (void *)123L;
+	ip[9] = (int *)123L;
+	ip[10] = (void *)(long)123;
+	ip[11] = (int *)(long)123;
+}
+
+/*
+ * check-name: store constants to pointer
+ * check-command: sparse-llvm $file
+ * check-output-ignore
+ */