diff options
Diffstat (limited to 'llvm/docs/CallGraphSection.md')
| -rw-r--r-- | llvm/docs/CallGraphSection.md | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/llvm/docs/CallGraphSection.md b/llvm/docs/CallGraphSection.md new file mode 100644 index 0000000..8b18727 --- /dev/null +++ b/llvm/docs/CallGraphSection.md @@ -0,0 +1,18 @@ +# .callgraph Section Layout + +The `.callgraph` section is used to store call graph information for each function. The section contains a series of records, with each record corresponding to a single function. + +## Per Function Record Layout + +Each record in the `.callgraph` section has the following binary layout: + +| Field | Type | Size (bits) | Description | +| -------------------------------------- | ------------- | ----------- | ------------------------------------------------------------------------------------------------------- | +| Format Version | `uint8_t` | 8 | The version of the record format. The current version is 0. | +| Flags | `uint8_t` | 8 | A bitfield where: Bit 0 is set if the function is a potential indirect call target; Bit 1 is set if there are direct callees; Bit 2 is set if there are indirect callees. The remaining 5 bits are reserved. | +| Function Entry PC | `uintptr_t` | 32/64 | The address of the function's entry point. | +| Function Type ID | `uint64_t` | 64 | The type ID of the function. This field is non-zero if the function is a potential indirect call target and its type is known. | +| Number of Unique Direct Callees | `ULEB128` | Variable | The number of unique direct call destinations from this function. This field is only present if there is at least one direct callee. | +| Direct Callees Array | `uintptr_t[]` | Variable | An array of unique direct callee entry point addresses. This field is only present if there is at least one direct callee. | +| Number of Unique Indirect Target Type IDs| `ULEB128` | Variable | The number of unique indirect call target type IDs. This field is only present if there is at least one indirect target type ID. | +| Indirect Target Type IDs Array | `uint64_t[]` | Variable | An array of unique indirect call target type IDs. This field is only present if there is at least one indirect target type ID. | |