[clang-c] introduce queries on GCC-style inline assembly statements (#143424)

[Discourse
link](https://discourse.llvm.org/t/a-small-proposal-for-extraction-of-inline-assembly-block-information/86658)

We strive for exposing such information using existing stable ABIs. In
doing so, queries are limited to what the original source holds or the
LLVM IR `asm` block would expose in connection with attributes that the
queries are concerned.

These APIs opens new opportunities for `rust-bindgen` to translate
inline assemblies in reasonably cases into Rust inline assembly blocks,
which would further aid better interoperability with other existing
code.

---------

Signed-off-by: Xiangfei Ding <dingxiangfei2009@protonmail.ch>

1 files changed, 124 insertions, 1 deletions

diff --git a/clang/include/clang-c/Index.h b/clang/include/clang-c/Index.h
index e4cb4327fbaa..c35311c88641 100644
--- a/clang/include/clang-c/Index.h
+++ b/clang/include/clang-c/Index.h
@@ -36,7 +36,7 @@
 #define CINDEX_VERSION_MAJOR 0
 #define CINDEX_VERSION_MINOR 64
 
-#define CINDEX_VERSION_ENCODE(major, minor) (((major)*10000) + ((minor)*1))
+#define CINDEX_VERSION_ENCODE(major, minor) (((major) * 10000) + ((minor) * 1))
 
 #define CINDEX_VERSION                                                         \
   CINDEX_VERSION_ENCODE(CINDEX_VERSION_MAJOR, CINDEX_VERSION_MINOR)
@@ -4500,6 +4500,129 @@ CINDEX_LINKAGE CXStringSet *clang_Cursor_getObjCManglings(CXCursor);
  */
 
 /**
+ * \defgroup CINDEX_MODULE Inline Assembly introspection
+ *
+ * The functions in this group provide access to information about GCC-style
+ * inline assembly statements.
+ *
+ * @{
+ */
+
+/**
+ * Given a CXCursor_GCCAsmStmt cursor, return the assembly template string.
+ * As per LLVM IR Assembly Template language, template placeholders for
+ * inputs and outputs are either of the form $N where N is a decimal number
+ * as an index into the input-output specification,
+ * or ${N:M} where N is a decimal number also as an index into the
+ * input-output specification and M is the template argument modifier.
+ * The index N in both cases points into the the total inputs and outputs,
+ * or more specifically, into the list of outputs followed by the inputs,
+ * starting from index 0 as the first available template argument.
+ *
+ * This function also returns a valid empty string if the cursor does not point
+ * at a GCC inline assembly block.
+ *
+ * Users are responsible for releasing the allocation of returned string via
+ * \c clang_disposeString.
+ */
+
+CINDEX_LINKAGE CXString clang_Cursor_getGCCAssemblyTemplate(CXCursor);
+
+/**
+ * Given a CXCursor_GCCAsmStmt cursor, check if the assembly block has goto
+ * labels.
+ * This function also returns 0 if the cursor does not point at a GCC inline
+ * assembly block.
+ */
+
+CINDEX_LINKAGE unsigned clang_Cursor_isGCCAssemblyHasGoto(CXCursor);
+
+/**
+ * Given a CXCursor_GCCAsmStmt cursor, count the number of outputs.
+ * This function also returns 0 if the cursor does not point at a GCC inline
+ * assembly block.
+ */
+
+CINDEX_LINKAGE unsigned clang_Cursor_getGCCAssemblyNumOutputs(CXCursor);
+
+/**
+ * Given a CXCursor_GCCAsmStmt cursor, count the number of inputs.
+ * This function also returns 0 if the cursor does not point at a GCC inline
+ * assembly block.
+ */
+
+CINDEX_LINKAGE unsigned clang_Cursor_getGCCAssemblyNumInputs(CXCursor);
+
+/**
+ * Given a CXCursor_GCCAsmStmt cursor, get the constraint and expression cursor
+ * to the Index-th input.
+ * This function returns 1 when the cursor points at a GCC inline assembly
+ * statement, `Index` is within bounds and both the `Constraint` and `Expr` are
+ * not NULL.
+ * Otherwise, this function returns 0 but leaves `Constraint` and `Expr`
+ * intact.
+ *
+ * Users are responsible for releasing the allocation of `Constraint` via
+ * \c clang_disposeString.
+ */
+
+CINDEX_LINKAGE unsigned clang_Cursor_getGCCAssemblyInput(CXCursor Cursor,
+                                                         unsigned Index,
+                                                         CXString *Constraint,
+                                                         CXCursor *Expr);
+
+/**
+ * Given a CXCursor_GCCAsmStmt cursor, get the constraint and expression cursor
+ * to the Index-th output.
+ * This function returns 1 when the cursor points at a GCC inline assembly
+ * statement, `Index` is within bounds and both the `Constraint` and `Expr` are
+ * not NULL.
+ * Otherwise, this function returns 0 but leaves `Constraint` and `Expr`
+ * intact.
+ *
+ * Users are responsible for releasing the allocation of `Constraint` via
+ * \c clang_disposeString.
+ */
+
+CINDEX_LINKAGE unsigned clang_Cursor_getGCCAssemblyOutput(CXCursor Cursor,
+                                                          unsigned Index,
+                                                          CXString *Constraint,
+                                                          CXCursor *Expr);
+
+/**
+ * Given a CXCursor_GCCAsmStmt cursor, count the clobbers in it.
+ * This function also returns 0 if the cursor does not point at a GCC inline
+ * assembly block.
+ */
+
+CINDEX_LINKAGE unsigned clang_Cursor_getGCCAssemblyNumClobbers(CXCursor Cursor);
+
+/**
+ * Given a CXCursor_GCCAsmStmt cursor, get the Index-th clobber of it.
+ * This function returns a valid empty string if the cursor does not point
+ * at a GCC inline assembly block or `Index` is out of bounds.
+ *
+ * Users are responsible for releasing the allocation of returned string via
+ * \c clang_disposeString.
+ */
+
+CINDEX_LINKAGE CXString clang_Cursor_getGCCAssemblyClobber(CXCursor Cursor,
+                                                           unsigned Index);
+
+/**
+ * Given a CXCursor_GCCAsmStmt cursor, check if the inline assembly is
+ * `volatile`.
+ * This function returns 0 if the cursor does not point at a GCC inline
+ * assembly block.
+ */
+
+CINDEX_LINKAGE unsigned clang_Cursor_isGCCAssemblyVolatile(CXCursor Cursor);
+
+/**
+ * @}
+ */
+
+/**
  * \defgroup CINDEX_MODULE Module introspection
  *
  * The functions in this group provide access to information about modules.