[jit] Improvements to API documentation within header file
David Malcolm
dmalcolm@redhat.com
Fri Oct 18 04:28:00 GMT 2013
I've committed this to dmalcolm/jit:
gcc/jit/
* libgccjit.h: Add and reword comments throughout.
---
gcc/jit/ChangeLog.jit | 4 ++
gcc/jit/libgccjit.h | 114 +++++++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 107 insertions(+), 11 deletions(-)
diff --git a/gcc/jit/ChangeLog.jit b/gcc/jit/ChangeLog.jit
index 162c3de..d0c76fc 100644
--- a/gcc/jit/ChangeLog.jit
+++ b/gcc/jit/ChangeLog.jit
@@ -1,5 +1,9 @@
2013-10-17 David Malcolm <dmalcolm@redhat.com>
+ * libgccjit.h: Add and reword comments throughout.
+
+2013-10-17 David Malcolm <dmalcolm@redhat.com>
+
* TODO.rst: Update.
2013-10-16 David Malcolm <dmalcolm@redhat.com>
diff --git a/gcc/jit/libgccjit.h b/gcc/jit/libgccjit.h
index 3d70b9b..e4b8de6 100644
--- a/gcc/jit/libgccjit.h
+++ b/gcc/jit/libgccjit.h
@@ -210,11 +210,11 @@ gcc_jit_context_set_bool_option (gcc_jit_context *ctxt,
enum gcc_jit_bool_option opt,
int value);
+/* This actually calls into GCC and runs the build, all
+ in a mutex for now. The result is a wrapper around a .so file.
+ It can only be called once on a given context. */
extern gcc_jit_result *
gcc_jit_context_compile (gcc_jit_context *ctxt);
- /* This actually calls into GCC and runs the build, all
- in a mutex for now. The result is a wrapper around a .so file.
- Can we only call this once on a given context? */
/* Locate a given function within the built machine code.
@@ -224,9 +224,12 @@ extern void *
gcc_jit_result_get_code (gcc_jit_result *result,
const char *funcname);
+/* Once we're done with the code, this unloads the built .so file.
+ This cleans up the result; after calling this, it's no longer
+ valid to use the result. */
extern void
gcc_jit_result_release (gcc_jit_result *result);
- /* Once we're done with the code, this unloads the built .so file: */
+
/**********************************************************************
Functions for use within the code factory.
@@ -238,7 +241,18 @@ gcc_jit_result_release (gcc_jit_result *result);
All (const char *) string arguments passed to these functions are
copied, so you don't need to keep them around. Note that this *isn't*
the case for other parts of the API.
+
+ You create code by adding a sequence of statements to a function.
+ Control flow is expressed using labels, rather than by explicitly
+ managing blocks. If you have blocks, you can simply create labels
+ for the start of each block. You can even create labels for every
+ instruction in your language; unused labels will be optimized away.
+ **********************************************************************/
+
+/**********************************************************************
+ Debugging information.
**********************************************************************/
+
/* Creating source code locations for use by the debugger.
Line and column numbers are 1-based. */
extern gcc_jit_location *
@@ -247,6 +261,11 @@ gcc_jit_context_new_location (gcc_jit_context *ctxt,
int line,
int column);
+
+/**********************************************************************
+ Types.
+ **********************************************************************/
+
/* Access to specific types. */
extern gcc_jit_type *
gcc_jit_context_get_void_type (gcc_jit_context *ctxt);
@@ -264,9 +283,12 @@ extern gcc_jit_type *
gcc_jit_context_get_double_type (gcc_jit_context *ctxt);
/* Constructing new types. */
+
+/* Given type "T", get type "T*". */
extern gcc_jit_type *
gcc_jit_type_get_pointer (gcc_jit_type *type);
+/* Given type "T", get type "const T". */
extern gcc_jit_type *
gcc_jit_type_get_const (gcc_jit_type *type);
@@ -284,7 +306,9 @@ gcc_jit_context_new_struct_type (gcc_jit_context *ctxt,
int num_fields,
gcc_jit_field **fields);
-/* Constructing functions. */
+/**********************************************************************
+ Constructing functions.
+ **********************************************************************/
extern gcc_jit_param *
gcc_jit_context_new_param (gcc_jit_context *ctxt,
gcc_jit_location *loc,
@@ -329,6 +353,10 @@ extern gcc_jit_label *
gcc_jit_function_new_forward_label (gcc_jit_function *func,
const char *name);
+/**********************************************************************
+ lvalues, rvalues and expressions.
+ **********************************************************************/
+
extern gcc_jit_lvalue *
gcc_jit_context_new_global (gcc_jit_context *ctxt,
gcc_jit_location *loc,
@@ -409,22 +437,44 @@ gcc_jit_function_new_local (gcc_jit_function *func,
gcc_jit_type *type,
const char *name);
+/**********************************************************************
+ Statement-creation.
+ **********************************************************************/
+
/* Add evaluation of an rvalue, discarding the result
- (e.g. a function call that "returns" void). */
+ (e.g. a function call that "returns" void).
+
+ This is equivalent to this C code:
+
+ (void)expression;
+*/
extern void
gcc_jit_function_add_eval (gcc_jit_function *func,
gcc_jit_location *loc,
gcc_jit_rvalue *rvalue);
+/* Add evaluation of an rvalue, assigning the result to the given
+ lvalue.
+
+ This is roughly equivalent to this C code:
+
+ lvalue = rvalue;
+*/
extern void
gcc_jit_function_add_assignment (gcc_jit_function *func,
gcc_jit_location *loc,
gcc_jit_lvalue *lvalue,
gcc_jit_rvalue *rvalue);
-/**
- Modify an lvalue (analogous to "+=" and friends)
- */
+/* Add evaluation of an rvalue, using the result to modify an
+ lvalue.
+
+ This is analogous to "+=" and friends:
+
+ lvalue += rvalue;
+ lvalue *= rvalue;
+ lvalue /= rvalue;
+ etc */
extern void
gcc_jit_function_add_assignment_op (gcc_jit_function *func,
gcc_jit_location *loc,
@@ -432,6 +482,23 @@ gcc_jit_function_add_assignment_op (gcc_jit_function *func,
enum gcc_jit_binary_op op,
gcc_jit_rvalue *rvalue);
+/* Add evaluation of an rvalue, branching on the result to the
+ appropriate label.
+
+ This is roughly equivalent to this C code:
+
+ if (boolval)
+ goto on_true;
+ else
+ goto on_false;
+
+ on_true must be non-NULL.
+
+ on_false may be NULL, in which case this is roughly equivalent to:
+
+ if (boolval)
+ goto on_true;
+*/
extern void
gcc_jit_function_add_conditional (gcc_jit_function *func,
gcc_jit_location *loc,
@@ -439,21 +506,47 @@ gcc_jit_function_add_conditional (gcc_jit_function *func,
gcc_jit_label *on_true,
gcc_jit_label *on_false);
+/* Add a label at the current location in the function.
+
+ This is roughly equivalent to this C code:
+
+ name:
+*/
extern gcc_jit_label *
gcc_jit_function_add_label (gcc_jit_function *func,
gcc_jit_location *loc,
const char *name);
+/* Place a pre-existing label at the current location in the function.
+
+ This is roughly equivalent to this C code:
+
+ name:
+
+ The label must not have already been placed. */
extern void
gcc_jit_function_place_forward_label (gcc_jit_function *func,
gcc_jit_location *loc,
gcc_jit_label *lab);
+/* Add a jump from the current location in the function to the given
+ label.
+
+ This is roughly equivalent to this C code:
+
+ goto target;
+*/
extern void
gcc_jit_function_add_jump (gcc_jit_function *func,
gcc_jit_location *loc,
gcc_jit_label *target);
+/* Add evaluation of an rvalue, returning the value.
+
+ This is roughly equivalent to this C code:
+
+ return expression;
+*/
extern void
gcc_jit_function_add_return (gcc_jit_function *func,
gcc_jit_location *loc,
@@ -466,8 +559,7 @@ gcc_jit_function_add_return (gcc_jit_function *func,
}
Statements will be added to the body of the loop until
- gcc_jit_loop_end is called.
-*/
+ gcc_jit_loop_end is called. */
extern gcc_jit_loop *
gcc_jit_function_new_loop (gcc_jit_function *func,
gcc_jit_location *loc,
--
1.7.11.7
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