[LLVM][C API] Support Value extraction from a MetadataAsValue. #105501
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@llvm/pr-subscribers-llvm-ir Author: Tim Besard (maleadt) ChangesIt is already possible to extract the Metadata node contained in a MetadataAsValue using the C API: julia> md = MDString("foo")
!"foo"
julia> mav = Value(LLVM.API.LLVMMetadataAsValue(context(), md));
julia> typeof(Metadata(LLVM.API.LLVMValueAsMetadata(mav)))
MDString
julia> Metadata(LLVM.API.LLVMValueAsMetadata(mav)) == md
trueHowever, julia> val = PointerNull(LLVM.PointerType(LLVM.Int8Type()))
i8* null
julia> vam = Metadata(LLVM.API.LLVMValueAsMetadata(val));
julia> typeof(Value(LLVM.API.LLVMMetadataAsValue(context(), vam)))
LLVM.MetadataAsValue
julia> Value(LLVM.API.LLVMMetadataAsValue(context(), vam)) == val
falseThis PR makes Full diff: https://github.com/llvm/llvm-project/pull/105501.diff 4 Files Affected:
diff --git a/llvm/lib/IR/Core.cpp b/llvm/lib/IR/Core.cpp
index 7665385025bd91..f4708bc18b3f8b 100644
--- a/llvm/lib/IR/Core.cpp
+++ b/llvm/lib/IR/Core.cpp
@@ -1328,8 +1328,12 @@ LLVMValueRef LLVMMDNode(LLVMValueRef *Vals, unsigned Count) {
return LLVMMDNodeInContext(LLVMGetGlobalContext(), Vals, Count);
}
-LLVMValueRef LLVMMetadataAsValue(LLVMContextRef C, LLVMMetadataRef MD) {
- return wrap(MetadataAsValue::get(*unwrap(C), unwrap(MD)));
+LLVMValueRef LLVMMetadataAsValue(LLVMContextRef C, LLVMMetadataRef Metadata) {
+ auto *MD = unwrap(Metadata);
+ if (auto *VAM = dyn_cast<ValueAsMetadata>(MD))
+ return wrap(VAM->getValue());
+ else
+ return wrap(MetadataAsValue::get(*unwrap(C), MD));
}
LLVMMetadataRef LLVMValueAsMetadata(LLVMValueRef Val) {
diff --git a/llvm/test/Bindings/llvm-c/vam_mav_extract.ll b/llvm/test/Bindings/llvm-c/vam_mav_extract.ll
new file mode 100644
index 00000000000000..31640c460ceab7
--- /dev/null
+++ b/llvm/test/Bindings/llvm-c/vam_mav_extract.ll
@@ -0,0 +1,2 @@
+; RUN: llvm-c-test --vam-mav-extract < /dev/null
+; This used to trigger an assertion
diff --git a/llvm/tools/llvm-c-test/llvm-c-test.h b/llvm/tools/llvm-c-test/llvm-c-test.h
index 1da6596cd5a8f2..44790e6a3bc8b5 100644
--- a/llvm/tools/llvm-c-test/llvm-c-test.h
+++ b/llvm/tools/llvm-c-test/llvm-c-test.h
@@ -45,6 +45,7 @@ int llvm_add_named_metadata_operand(void);
int llvm_set_metadata(void);
int llvm_replace_md_operand(void);
int llvm_is_a_value_as_metadata(void);
+int llvm_vam_mav_extract(void);
// object.c
int llvm_object_list_sections(void);
diff --git a/llvm/tools/llvm-c-test/main.c b/llvm/tools/llvm-c-test/main.c
index 8be9ea06fc68da..5a1f792fb941a3 100644
--- a/llvm/tools/llvm-c-test/main.c
+++ b/llvm/tools/llvm-c-test/main.c
@@ -56,6 +56,8 @@ static void print_usage(void) {
fprintf(stderr, " * --is-a-value-as-metadata\n");
fprintf(stderr,
" Run test for checking if LLVMValueRef is a ValueAsMetadata\n");
+ fprintf(stderr, " * --vam-mav-extract\n");
+ fprintf(stderr, " Run test for extracting data from ValueAsMetadata and MetadataAsValue\n");
fprintf(stderr, " * --echo\n");
fprintf(stderr, " Read bitcode file from stdin - print it back out\n\n");
fprintf(stderr, " * --test-diagnostic-handler\n");
@@ -101,6 +103,8 @@ int main(int argc, char **argv) {
return llvm_replace_md_operand();
} else if (argc == 2 && !strcmp(argv[1], "--is-a-value-as-metadata")) {
return llvm_is_a_value_as_metadata();
+ } else if (argc == 2 && !strcmp(argv[1], "--vam-mav-extract")) {
+ return llvm_vam_mav_extract();
} else if (argc == 2 && !strcmp(argv[1], "--test-function-attributes")) {
return llvm_test_function_attributes();
} else if (argc == 2 && !strcmp(argv[1], "--test-callsite-attributes")) {
diff --git a/llvm/tools/llvm-c-test/metadata.c b/llvm/tools/llvm-c-test/metadata.c
index 4fe8c00c57481b..a08ebacb49696e 100644
--- a/llvm/tools/llvm-c-test/metadata.c
+++ b/llvm/tools/llvm-c-test/metadata.c
@@ -80,7 +80,7 @@ int llvm_is_a_value_as_metadata(void) {
LLVMContextRef Context = LLVMGetModuleContext(M);
{
- LLVMValueRef Int = LLVMConstInt(LLVMInt32Type(), 0, 0);
+ LLVMValueRef Int = LLVMConstInt(LLVMInt32TypeInContext(Context), 0, 0);
LLVMValueRef NodeMD = LLVMMDNode(&Int, 1);
assert(LLVMIsAValueAsMetadata(NodeMD) == NodeMD);
(void)NodeMD;
@@ -98,3 +98,21 @@ int llvm_is_a_value_as_metadata(void) {
return 0;
}
+
+int llvm_vam_mav_extract(void) {
+ LLVMModuleRef M = LLVMModuleCreateWithName("Mod");
+ LLVMContextRef Context = LLVMGetModuleContext(M);
+
+ LLVMValueRef Val = LLVMConstInt(LLVMInt32TypeInContext(Context), 0, 0);
+ LLVMMetadataRef MD = LLVMMDStringInContext2(Context, "foo", 3);
+
+ // construction
+ LLVMValueRef MAV = LLVMMetadataAsValue(Context, MD);
+ LLVMMetadataRef VAM = LLVMValueAsMetadata(Val);
+
+ // extraction
+ assert(LLVMMetadataAsValue(Context, VAM) == Val);
+ assert(LLVMValueAsMetadata(MAV) == MD);
+
+ return 0;
+}
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✅ With the latest revision this PR passed the C/C++ code formatter. |
It is already possible to extract the underlying Metadata from a ValueAsMetadata.
7 tasks
nikic
reviewed
Aug 27, 2024
I guess that's fair. It seemed silly to create a Or should we switch to a more explicit API for extracting contained values from a ValueAsMetadata / metadata from a MetadataAsValue? I always found the explicit unwrapping behavior of |
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It is already possible to extract the Metadata node contained in a MetadataAsValue using the C API:
However,
LLVMMetadataAsValuecurrently does not support getting the value from aValueAsMetadata:This PR makes
LLVMValueAsMetadatabehave likeLLVMMetadataAsValue, returning the contained data when possible.We've been carrying this patch for a while in LLVM.jl.